diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-npcm7xx.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-npcm7xx.c | 2415 |
1 files changed, 2415 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c new file mode 100644 index 0000000000..ae4bae63ad --- /dev/null +++ b/drivers/i2c/busses/i2c-npcm7xx.c @@ -0,0 +1,2415 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Nuvoton NPCM7xx I2C Controller driver + * + * Copyright (C) 2020 Nuvoton Technologies tali.perry@nuvoton.com + */ +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/debugfs.h> +#include <linux/errno.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/iopoll.h> +#include <linux/irq.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +enum i2c_mode { + I2C_MASTER, + I2C_SLAVE, +}; + +/* + * External I2C Interface driver xfer indication values, which indicate status + * of the bus. + */ +enum i2c_state_ind { + I2C_NO_STATUS_IND = 0, + I2C_SLAVE_RCV_IND, + I2C_SLAVE_XMIT_IND, + I2C_SLAVE_XMIT_MISSING_DATA_IND, + I2C_SLAVE_RESTART_IND, + I2C_SLAVE_DONE_IND, + I2C_MASTER_DONE_IND, + I2C_NACK_IND, + I2C_BUS_ERR_IND, + I2C_WAKE_UP_IND, + I2C_BLOCK_BYTES_ERR_IND, + I2C_SLAVE_RCV_MISSING_DATA_IND, +}; + +/* + * Operation type values (used to define the operation currently running) + * module is interrupt driven, on each interrupt the current operation is + * checked to see if the module is currently reading or writing. + */ +enum i2c_oper { + I2C_NO_OPER = 0, + I2C_WRITE_OPER, + I2C_READ_OPER, +}; + +/* I2C Bank (module had 2 banks of registers) */ +enum i2c_bank { + I2C_BANK_0 = 0, + I2C_BANK_1, +}; + +/* Internal I2C states values (for the I2C module state machine). */ +enum i2c_state { + I2C_DISABLE = 0, + I2C_IDLE, + I2C_MASTER_START, + I2C_SLAVE_MATCH, + I2C_OPER_STARTED, + I2C_STOP_PENDING, +}; + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +/* Module supports setting multiple own slave addresses */ +enum i2c_addr { + I2C_SLAVE_ADDR1 = 0, + I2C_SLAVE_ADDR2, + I2C_SLAVE_ADDR3, + I2C_SLAVE_ADDR4, + I2C_SLAVE_ADDR5, + I2C_SLAVE_ADDR6, + I2C_SLAVE_ADDR7, + I2C_SLAVE_ADDR8, + I2C_SLAVE_ADDR9, + I2C_SLAVE_ADDR10, + I2C_GC_ADDR, + I2C_ARP_ADDR, +}; +#endif + +/* init register and default value required to enable module */ +#define NPCM_I2CSEGCTL 0xE4 + +/* Common regs */ +#define NPCM_I2CSDA 0x00 +#define NPCM_I2CST 0x02 +#define NPCM_I2CCST 0x04 +#define NPCM_I2CCTL1 0x06 +#define NPCM_I2CADDR1 0x08 +#define NPCM_I2CCTL2 0x0A +#define NPCM_I2CADDR2 0x0C +#define NPCM_I2CCTL3 0x0E +#define NPCM_I2CCST2 0x18 +#define NPCM_I2CCST3 0x19 +#define I2C_VER 0x1F + +/* BANK 0 regs */ +#define NPCM_I2CADDR3 0x10 +#define NPCM_I2CADDR7 0x11 +#define NPCM_I2CADDR4 0x12 +#define NPCM_I2CADDR8 0x13 +#define NPCM_I2CADDR5 0x14 +#define NPCM_I2CADDR9 0x15 +#define NPCM_I2CADDR6 0x16 +#define NPCM_I2CADDR10 0x17 +#define NPCM_I2CCTL4 0x1A +#define NPCM_I2CCTL5 0x1B +#define NPCM_I2CSCLLT 0x1C /* SCL Low Time */ +#define NPCM_I2CFIF_CTL 0x1D /* FIFO Control */ +#define NPCM_I2CSCLHT 0x1E /* SCL High Time */ + +/* BANK 1 regs */ +#define NPCM_I2CFIF_CTS 0x10 /* Both FIFOs Control and Status */ +#define NPCM_I2CTXF_CTL 0x12 /* Tx-FIFO Control */ +#define NPCM_I2CT_OUT 0x14 /* Bus T.O. */ +#define NPCM_I2CPEC 0x16 /* PEC Data */ +#define NPCM_I2CTXF_STS 0x1A /* Tx-FIFO Status */ +#define NPCM_I2CRXF_STS 0x1C /* Rx-FIFO Status */ +#define NPCM_I2CRXF_CTL 0x1E /* Rx-FIFO Control */ + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +/* + * npcm_i2caddr array: + * The module supports having multiple own slave addresses. + * Since the addr regs are sprinkled all over the address space, + * use this array to get the address or each register. + */ +#define I2C_NUM_OWN_ADDR 2 +#define I2C_NUM_OWN_ADDR_SUPPORTED 2 + +static const int npcm_i2caddr[I2C_NUM_OWN_ADDR] = { + NPCM_I2CADDR1, NPCM_I2CADDR2, +}; +#endif + +/* NPCM_I2CST reg fields */ +#define NPCM_I2CST_XMIT BIT(0) /* Transmit mode */ +#define NPCM_I2CST_MASTER BIT(1) /* Master mode */ +#define NPCM_I2CST_NMATCH BIT(2) /* New match */ +#define NPCM_I2CST_STASTR BIT(3) /* Stall after start */ +#define NPCM_I2CST_NEGACK BIT(4) /* Negative ACK */ +#define NPCM_I2CST_BER BIT(5) /* Bus error */ +#define NPCM_I2CST_SDAST BIT(6) /* SDA status */ +#define NPCM_I2CST_SLVSTP BIT(7) /* Slave stop */ + +/* NPCM_I2CCST reg fields */ +#define NPCM_I2CCST_BUSY BIT(0) /* Busy */ +#define NPCM_I2CCST_BB BIT(1) /* Bus busy */ +#define NPCM_I2CCST_MATCH BIT(2) /* Address match */ +#define NPCM_I2CCST_GCMATCH BIT(3) /* Global call match */ +#define NPCM_I2CCST_TSDA BIT(4) /* Test SDA line */ +#define NPCM_I2CCST_TGSCL BIT(5) /* Toggle SCL line */ +#define NPCM_I2CCST_MATCHAF BIT(6) /* Match address field */ +#define NPCM_I2CCST_ARPMATCH BIT(7) /* ARP address match */ + +/* NPCM_I2CCTL1 reg fields */ +#define NPCM_I2CCTL1_START BIT(0) /* Generate start condition */ +#define NPCM_I2CCTL1_STOP BIT(1) /* Generate stop condition */ +#define NPCM_I2CCTL1_INTEN BIT(2) /* Interrupt enable */ +#define NPCM_I2CCTL1_EOBINTE BIT(3) +#define NPCM_I2CCTL1_ACK BIT(4) +#define NPCM_I2CCTL1_GCMEN BIT(5) /* Global call match enable */ +#define NPCM_I2CCTL1_NMINTE BIT(6) /* New match interrupt enable */ +#define NPCM_I2CCTL1_STASTRE BIT(7) /* Stall after start enable */ + +/* RW1S fields (inside a RW reg): */ +#define NPCM_I2CCTL1_RWS \ + (NPCM_I2CCTL1_START | NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK) + +/* npcm_i2caddr reg fields */ +#define NPCM_I2CADDR_A GENMASK(6, 0) /* Address */ +#define NPCM_I2CADDR_SAEN BIT(7) /* Slave address enable */ + +/* NPCM_I2CCTL2 reg fields */ +#define I2CCTL2_ENABLE BIT(0) /* Module enable */ +#define I2CCTL2_SCLFRQ6_0 GENMASK(7, 1) /* Bits 0:6 of frequency divisor */ + +/* NPCM_I2CCTL3 reg fields */ +#define I2CCTL3_SCLFRQ8_7 GENMASK(1, 0) /* Bits 7:8 of frequency divisor */ +#define I2CCTL3_ARPMEN BIT(2) /* ARP match enable */ +#define I2CCTL3_IDL_START BIT(3) +#define I2CCTL3_400K_MODE BIT(4) +#define I2CCTL3_BNK_SEL BIT(5) +#define I2CCTL3_SDA_LVL BIT(6) +#define I2CCTL3_SCL_LVL BIT(7) + +/* NPCM_I2CCST2 reg fields */ +#define NPCM_I2CCST2_MATCHA1F BIT(0) +#define NPCM_I2CCST2_MATCHA2F BIT(1) +#define NPCM_I2CCST2_MATCHA3F BIT(2) +#define NPCM_I2CCST2_MATCHA4F BIT(3) +#define NPCM_I2CCST2_MATCHA5F BIT(4) +#define NPCM_I2CCST2_MATCHA6F BIT(5) +#define NPCM_I2CCST2_MATCHA7F BIT(5) +#define NPCM_I2CCST2_INTSTS BIT(7) + +/* NPCM_I2CCST3 reg fields */ +#define NPCM_I2CCST3_MATCHA8F BIT(0) +#define NPCM_I2CCST3_MATCHA9F BIT(1) +#define NPCM_I2CCST3_MATCHA10F BIT(2) +#define NPCM_I2CCST3_EO_BUSY BIT(7) + +/* NPCM_I2CCTL4 reg fields */ +#define I2CCTL4_HLDT GENMASK(5, 0) +#define I2CCTL4_LVL_WE BIT(7) + +/* NPCM_I2CCTL5 reg fields */ +#define I2CCTL5_DBNCT GENMASK(3, 0) + +/* NPCM_I2CFIF_CTS reg fields */ +#define NPCM_I2CFIF_CTS_RXF_TXE BIT(1) +#define NPCM_I2CFIF_CTS_RFTE_IE BIT(3) +#define NPCM_I2CFIF_CTS_CLR_FIFO BIT(6) +#define NPCM_I2CFIF_CTS_SLVRSTR BIT(7) + +/* NPCM_I2CTXF_CTL reg field */ +#define NPCM_I2CTXF_CTL_THR_TXIE BIT(6) + +/* NPCM_I2CT_OUT reg fields */ +#define NPCM_I2CT_OUT_TO_CKDIV GENMASK(5, 0) +#define NPCM_I2CT_OUT_T_OUTIE BIT(6) +#define NPCM_I2CT_OUT_T_OUTST BIT(7) + +/* NPCM_I2CTXF_STS reg fields */ +#define NPCM_I2CTXF_STS_TX_THST BIT(6) + +/* NPCM_I2CRXF_STS reg fields */ +#define NPCM_I2CRXF_STS_RX_THST BIT(6) + +/* NPCM_I2CFIF_CTL reg fields */ +#define NPCM_I2CFIF_CTL_FIFO_EN BIT(4) + +/* NPCM_I2CRXF_CTL reg fields */ +#define NPCM_I2CRXF_CTL_THR_RXIE BIT(6) + +#define MAX_I2C_HW_FIFO_SIZE 32 + +/* I2C_VER reg fields */ +#define I2C_VER_VERSION GENMASK(6, 0) +#define I2C_VER_FIFO_EN BIT(7) + +/* stall/stuck timeout in us */ +#define DEFAULT_STALL_COUNT 25 + +/* SCLFRQ field position */ +#define SCLFRQ_0_TO_6 GENMASK(6, 0) +#define SCLFRQ_7_TO_8 GENMASK(8, 7) + +/* supported clk settings. values in Hz. */ +#define I2C_FREQ_MIN_HZ 10000 +#define I2C_FREQ_MAX_HZ I2C_MAX_FAST_MODE_PLUS_FREQ + +struct npcm_i2c_data { + u8 fifo_size; + u32 segctl_init_val; + u8 txf_sts_tx_bytes; + u8 rxf_sts_rx_bytes; + u8 rxf_ctl_last_pec; +}; + +static const struct npcm_i2c_data npxm7xx_i2c_data = { + .fifo_size = 16, + .segctl_init_val = 0x0333F000, + .txf_sts_tx_bytes = GENMASK(4, 0), + .rxf_sts_rx_bytes = GENMASK(4, 0), + .rxf_ctl_last_pec = BIT(5), +}; + +static const struct npcm_i2c_data npxm8xx_i2c_data = { + .fifo_size = 32, + .segctl_init_val = 0x9333F000, + .txf_sts_tx_bytes = GENMASK(5, 0), + .rxf_sts_rx_bytes = GENMASK(5, 0), + .rxf_ctl_last_pec = BIT(7), +}; + +/* Status of one I2C module */ +struct npcm_i2c { + struct i2c_adapter adap; + struct device *dev; + unsigned char __iomem *reg; + const struct npcm_i2c_data *data; + spinlock_t lock; /* IRQ synchronization */ + struct completion cmd_complete; + int cmd_err; + struct i2c_msg *msgs; + int msgs_num; + int num; + u32 apb_clk; + struct i2c_bus_recovery_info rinfo; + enum i2c_state state; + enum i2c_oper operation; + enum i2c_mode master_or_slave; + enum i2c_state_ind stop_ind; + u8 dest_addr; + u8 *rd_buf; + u16 rd_size; + u16 rd_ind; + u8 *wr_buf; + u16 wr_size; + u16 wr_ind; + bool fifo_use; + u16 PEC_mask; /* PEC bit mask per slave address */ + bool PEC_use; + bool read_block_use; + unsigned long int_time_stamp; + unsigned long bus_freq; /* in Hz */ +#if IS_ENABLED(CONFIG_I2C_SLAVE) + u8 own_slave_addr; + struct i2c_client *slave; + int slv_rd_size; + int slv_rd_ind; + int slv_wr_size; + int slv_wr_ind; + u8 slv_rd_buf[MAX_I2C_HW_FIFO_SIZE]; + u8 slv_wr_buf[MAX_I2C_HW_FIFO_SIZE]; +#endif + struct dentry *debugfs; /* debugfs device directory */ + u64 ber_cnt; + u64 rec_succ_cnt; + u64 rec_fail_cnt; + u64 nack_cnt; + u64 timeout_cnt; + u64 tx_complete_cnt; +}; + +static inline void npcm_i2c_select_bank(struct npcm_i2c *bus, + enum i2c_bank bank) +{ + u8 i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3); + + if (bank == I2C_BANK_0) + i2cctl3 = i2cctl3 & ~I2CCTL3_BNK_SEL; + else + i2cctl3 = i2cctl3 | I2CCTL3_BNK_SEL; + iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3); +} + +static void npcm_i2c_init_params(struct npcm_i2c *bus) +{ + bus->stop_ind = I2C_NO_STATUS_IND; + bus->rd_size = 0; + bus->wr_size = 0; + bus->rd_ind = 0; + bus->wr_ind = 0; + bus->read_block_use = false; + bus->int_time_stamp = 0; + bus->PEC_use = false; + bus->PEC_mask = 0; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (bus->slave) + bus->master_or_slave = I2C_SLAVE; +#endif +} + +static inline void npcm_i2c_wr_byte(struct npcm_i2c *bus, u8 data) +{ + iowrite8(data, bus->reg + NPCM_I2CSDA); +} + +static inline u8 npcm_i2c_rd_byte(struct npcm_i2c *bus) +{ + return ioread8(bus->reg + NPCM_I2CSDA); +} + +static int npcm_i2c_get_SCL(struct i2c_adapter *_adap) +{ + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + + return !!(I2CCTL3_SCL_LVL & ioread8(bus->reg + NPCM_I2CCTL3)); +} + +static int npcm_i2c_get_SDA(struct i2c_adapter *_adap) +{ + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + + return !!(I2CCTL3_SDA_LVL & ioread8(bus->reg + NPCM_I2CCTL3)); +} + +static inline u16 npcm_i2c_get_index(struct npcm_i2c *bus) +{ + if (bus->operation == I2C_READ_OPER) + return bus->rd_ind; + if (bus->operation == I2C_WRITE_OPER) + return bus->wr_ind; + return 0; +} + +/* quick protocol (just address) */ +static inline bool npcm_i2c_is_quick(struct npcm_i2c *bus) +{ + return bus->wr_size == 0 && bus->rd_size == 0; +} + +static void npcm_i2c_disable(struct npcm_i2c *bus) +{ + u8 i2cctl2; + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + int i; + + /* Slave addresses removal */ + for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR_SUPPORTED; i++) + iowrite8(0, bus->reg + npcm_i2caddr[i]); + +#endif + /* Disable module */ + i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2); + i2cctl2 = i2cctl2 & ~I2CCTL2_ENABLE; + iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2); + + bus->state = I2C_DISABLE; +} + +static void npcm_i2c_enable(struct npcm_i2c *bus) +{ + u8 i2cctl2 = ioread8(bus->reg + NPCM_I2CCTL2); + + i2cctl2 = i2cctl2 | I2CCTL2_ENABLE; + iowrite8(i2cctl2, bus->reg + NPCM_I2CCTL2); + bus->state = I2C_IDLE; +} + +/* enable\disable end of busy (EOB) interrupts */ +static inline void npcm_i2c_eob_int(struct npcm_i2c *bus, bool enable) +{ + u8 val; + + /* Clear EO_BUSY pending bit: */ + val = ioread8(bus->reg + NPCM_I2CCST3); + val = val | NPCM_I2CCST3_EO_BUSY; + iowrite8(val, bus->reg + NPCM_I2CCST3); + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~NPCM_I2CCTL1_RWS; + if (enable) + val |= NPCM_I2CCTL1_EOBINTE; + else + val &= ~NPCM_I2CCTL1_EOBINTE; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline bool npcm_i2c_tx_fifo_empty(struct npcm_i2c *bus) +{ + u8 tx_fifo_sts; + + tx_fifo_sts = ioread8(bus->reg + NPCM_I2CTXF_STS); + /* check if TX FIFO is not empty */ + if ((tx_fifo_sts & bus->data->txf_sts_tx_bytes) == 0) + return false; + + /* check if TX FIFO status bit is set: */ + return !!FIELD_GET(NPCM_I2CTXF_STS_TX_THST, tx_fifo_sts); +} + +static inline bool npcm_i2c_rx_fifo_full(struct npcm_i2c *bus) +{ + u8 rx_fifo_sts; + + rx_fifo_sts = ioread8(bus->reg + NPCM_I2CRXF_STS); + /* check if RX FIFO is not empty: */ + if ((rx_fifo_sts & bus->data->rxf_sts_rx_bytes) == 0) + return false; + + /* check if rx fifo full status is set: */ + return !!FIELD_GET(NPCM_I2CRXF_STS_RX_THST, rx_fifo_sts); +} + +static inline void npcm_i2c_clear_fifo_int(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CFIF_CTS); + val = (val & NPCM_I2CFIF_CTS_SLVRSTR) | NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(val, bus->reg + NPCM_I2CFIF_CTS); +} + +static inline void npcm_i2c_clear_tx_fifo(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CTXF_STS); + val = val | NPCM_I2CTXF_STS_TX_THST; + iowrite8(val, bus->reg + NPCM_I2CTXF_STS); +} + +static inline void npcm_i2c_clear_rx_fifo(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CRXF_STS); + val = val | NPCM_I2CRXF_STS_RX_THST; + iowrite8(val, bus->reg + NPCM_I2CRXF_STS); +} + +static void npcm_i2c_int_enable(struct npcm_i2c *bus, bool enable) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~NPCM_I2CCTL1_RWS; + if (enable) + val |= NPCM_I2CCTL1_INTEN; + else + val &= ~NPCM_I2CCTL1_INTEN; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_master_start(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_ACK); + val |= NPCM_I2CCTL1_START; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_master_stop(struct npcm_i2c *bus) +{ + u8 val; + + /* + * override HW issue: I2C may fail to supply stop condition in Master + * Write operation. + * Need to delay at least 5 us from the last int, before issueing a stop + */ + udelay(10); /* function called from interrupt, can't sleep */ + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~(NPCM_I2CCTL1_START | NPCM_I2CCTL1_ACK); + val |= NPCM_I2CCTL1_STOP; + iowrite8(val, bus->reg + NPCM_I2CCTL1); + + if (!bus->fifo_use) + return; + + npcm_i2c_select_bank(bus, I2C_BANK_1); + + if (bus->operation == I2C_READ_OPER) + npcm_i2c_clear_rx_fifo(bus); + else + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_clear_fifo_int(bus); + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); +} + +static inline void npcm_i2c_stall_after_start(struct npcm_i2c *bus, bool stall) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~NPCM_I2CCTL1_RWS; + if (stall) + val |= NPCM_I2CCTL1_STASTRE; + else + val &= ~NPCM_I2CCTL1_STASTRE; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_nack(struct npcm_i2c *bus) +{ + u8 val; + + val = ioread8(bus->reg + NPCM_I2CCTL1); + val &= ~(NPCM_I2CCTL1_STOP | NPCM_I2CCTL1_START); + val |= NPCM_I2CCTL1_ACK; + iowrite8(val, bus->reg + NPCM_I2CCTL1); +} + +static inline void npcm_i2c_clear_master_status(struct npcm_i2c *bus) +{ + u8 val; + + /* Clear NEGACK, STASTR and BER bits */ + val = NPCM_I2CST_BER | NPCM_I2CST_NEGACK | NPCM_I2CST_STASTR; + iowrite8(val, bus->reg + NPCM_I2CST); +} + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static void npcm_i2c_slave_int_enable(struct npcm_i2c *bus, bool enable) +{ + u8 i2cctl1; + + /* enable interrupt on slave match: */ + i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1); + i2cctl1 &= ~NPCM_I2CCTL1_RWS; + if (enable) + i2cctl1 |= NPCM_I2CCTL1_NMINTE; + else + i2cctl1 &= ~NPCM_I2CCTL1_NMINTE; + iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1); +} + +static int npcm_i2c_slave_enable(struct npcm_i2c *bus, enum i2c_addr addr_type, + u8 addr, bool enable) +{ + u8 i2cctl1; + u8 i2cctl3; + u8 sa_reg; + + sa_reg = (addr & 0x7F) | FIELD_PREP(NPCM_I2CADDR_SAEN, enable); + if (addr_type == I2C_GC_ADDR) { + i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1); + if (enable) + i2cctl1 |= NPCM_I2CCTL1_GCMEN; + else + i2cctl1 &= ~NPCM_I2CCTL1_GCMEN; + iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1); + return 0; + } else if (addr_type == I2C_ARP_ADDR) { + i2cctl3 = ioread8(bus->reg + NPCM_I2CCTL3); + if (enable) + i2cctl3 |= I2CCTL3_ARPMEN; + else + i2cctl3 &= ~I2CCTL3_ARPMEN; + iowrite8(i2cctl3, bus->reg + NPCM_I2CCTL3); + return 0; + } + if (addr_type > I2C_SLAVE_ADDR2 && addr_type <= I2C_SLAVE_ADDR10) + dev_err(bus->dev, "try to enable more than 2 SA not supported\n"); + + if (addr_type >= I2C_ARP_ADDR) + return -EFAULT; + + /* Set and enable the address */ + iowrite8(sa_reg, bus->reg + npcm_i2caddr[addr_type]); + npcm_i2c_slave_int_enable(bus, enable); + + return 0; +} +#endif + +static void npcm_i2c_reset(struct npcm_i2c *bus) +{ + /* + * Save I2CCTL1 relevant bits. It is being cleared when the module + * is disabled. + */ + u8 i2cctl1; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + u8 addr; +#endif + + i2cctl1 = ioread8(bus->reg + NPCM_I2CCTL1); + + npcm_i2c_disable(bus); + npcm_i2c_enable(bus); + + /* Restore NPCM_I2CCTL1 Status */ + i2cctl1 &= ~NPCM_I2CCTL1_RWS; + iowrite8(i2cctl1, bus->reg + NPCM_I2CCTL1); + + /* Clear BB (BUS BUSY) bit */ + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + iowrite8(0xFF, bus->reg + NPCM_I2CST); + + /* Clear and disable EOB */ + npcm_i2c_eob_int(bus, false); + + /* Clear all fifo bits: */ + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS); + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (bus->slave) { + addr = bus->slave->addr; + npcm_i2c_slave_enable(bus, I2C_SLAVE_ADDR1, addr, true); + } +#endif + + /* Clear status bits for spurious interrupts */ + npcm_i2c_clear_master_status(bus); + + bus->state = I2C_IDLE; +} + +static inline bool npcm_i2c_is_master(struct npcm_i2c *bus) +{ + return !!FIELD_GET(NPCM_I2CST_MASTER, ioread8(bus->reg + NPCM_I2CST)); +} + +static void npcm_i2c_callback(struct npcm_i2c *bus, + enum i2c_state_ind op_status, u16 info) +{ + struct i2c_msg *msgs; + int msgs_num; + bool do_complete = false; + + msgs = bus->msgs; + msgs_num = bus->msgs_num; + /* + * check that transaction was not timed-out, and msgs still + * holds a valid value. + */ + if (!msgs) + return; + + if (completion_done(&bus->cmd_complete)) + return; + + switch (op_status) { + case I2C_MASTER_DONE_IND: + bus->cmd_err = bus->msgs_num; + if (bus->tx_complete_cnt < ULLONG_MAX) + bus->tx_complete_cnt++; + fallthrough; + case I2C_BLOCK_BYTES_ERR_IND: + /* Master tx finished and all transmit bytes were sent */ + if (bus->msgs) { + if (msgs[0].flags & I2C_M_RD) + msgs[0].len = info; + else if (msgs_num == 2 && + msgs[1].flags & I2C_M_RD) + msgs[1].len = info; + } + do_complete = true; + break; + case I2C_NACK_IND: + /* MASTER transmit got a NACK before tx all bytes */ + bus->cmd_err = -ENXIO; + do_complete = true; + break; + case I2C_BUS_ERR_IND: + /* Bus error */ + bus->cmd_err = -EAGAIN; + do_complete = true; + break; + case I2C_WAKE_UP_IND: + /* I2C wake up */ + break; + default: + break; + } + + bus->operation = I2C_NO_OPER; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (bus->slave) + bus->master_or_slave = I2C_SLAVE; +#endif + if (do_complete) + complete(&bus->cmd_complete); +} + +static u8 npcm_i2c_fifo_usage(struct npcm_i2c *bus) +{ + if (bus->operation == I2C_WRITE_OPER) + return (bus->data->txf_sts_tx_bytes & + ioread8(bus->reg + NPCM_I2CTXF_STS)); + if (bus->operation == I2C_READ_OPER) + return (bus->data->rxf_sts_rx_bytes & + ioread8(bus->reg + NPCM_I2CRXF_STS)); + return 0; +} + +static void npcm_i2c_write_to_fifo_master(struct npcm_i2c *bus, u16 max_bytes) +{ + u8 size_free_fifo; + + /* + * Fill the FIFO, while the FIFO is not full and there are more bytes + * to write + */ + size_free_fifo = bus->data->fifo_size - npcm_i2c_fifo_usage(bus); + while (max_bytes-- && size_free_fifo) { + if (bus->wr_ind < bus->wr_size) + npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]); + else + npcm_i2c_wr_byte(bus, 0xFF); + size_free_fifo = bus->data->fifo_size - npcm_i2c_fifo_usage(bus); + } +} + +/* + * npcm_i2c_set_fifo: + * configure the FIFO before using it. If nread is -1 RX FIFO will not be + * configured. same for nwrite + */ +static void npcm_i2c_set_fifo(struct npcm_i2c *bus, int nread, int nwrite) +{ + u8 rxf_ctl = 0; + + if (!bus->fifo_use) + return; + npcm_i2c_select_bank(bus, I2C_BANK_1); + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_clear_rx_fifo(bus); + + /* configure RX FIFO */ + if (nread > 0) { + rxf_ctl = min_t(int, nread, bus->data->fifo_size); + + /* set LAST bit. if LAST is set next FIFO packet is nacked */ + if (nread <= bus->data->fifo_size) + rxf_ctl |= bus->data->rxf_ctl_last_pec; + + /* + * if we are about to read the first byte in blk rd mode, + * don't NACK it. If slave returns zero size HW can't NACK + * it immediately, it will read extra byte and then NACK. + */ + if (bus->rd_ind == 0 && bus->read_block_use) { + /* set fifo to read one byte, no last: */ + rxf_ctl = 1; + } + + /* set fifo size: */ + iowrite8(rxf_ctl, bus->reg + NPCM_I2CRXF_CTL); + } + + /* configure TX FIFO */ + if (nwrite > 0) { + if (nwrite > bus->data->fifo_size) + /* data to send is more then FIFO size. */ + iowrite8(bus->data->fifo_size, bus->reg + NPCM_I2CTXF_CTL); + else + iowrite8(nwrite, bus->reg + NPCM_I2CTXF_CTL); + + npcm_i2c_clear_tx_fifo(bus); + } +} + +static void npcm_i2c_read_fifo(struct npcm_i2c *bus, u8 bytes_in_fifo) +{ + u8 data; + + while (bytes_in_fifo--) { + data = npcm_i2c_rd_byte(bus); + if (bus->rd_ind < bus->rd_size) + bus->rd_buf[bus->rd_ind++] = data; + } +} + +static void npcm_i2c_master_abort(struct npcm_i2c *bus) +{ + /* Only current master is allowed to issue a stop condition */ + if (!npcm_i2c_is_master(bus)) + return; + + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + npcm_i2c_clear_master_status(bus); +} + +#if IS_ENABLED(CONFIG_I2C_SLAVE) +static u8 npcm_i2c_get_slave_addr(struct npcm_i2c *bus, enum i2c_addr addr_type) +{ + u8 slave_add; + + if (addr_type > I2C_SLAVE_ADDR2 && addr_type <= I2C_SLAVE_ADDR10) + dev_err(bus->dev, "get slave: try to use more than 2 SA not supported\n"); + + slave_add = ioread8(bus->reg + npcm_i2caddr[(int)addr_type]); + + return slave_add; +} + +static int npcm_i2c_remove_slave_addr(struct npcm_i2c *bus, u8 slave_add) +{ + int i; + + /* Set the enable bit */ + slave_add |= 0x80; + + for (i = I2C_SLAVE_ADDR1; i < I2C_NUM_OWN_ADDR_SUPPORTED; i++) { + if (ioread8(bus->reg + npcm_i2caddr[i]) == slave_add) + iowrite8(0, bus->reg + npcm_i2caddr[i]); + } + + return 0; +} + +static void npcm_i2c_write_fifo_slave(struct npcm_i2c *bus, u16 max_bytes) +{ + /* + * Fill the FIFO, while the FIFO is not full and there are more bytes + * to write + */ + npcm_i2c_clear_fifo_int(bus); + npcm_i2c_clear_tx_fifo(bus); + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); + while (max_bytes-- && bus->data->fifo_size != npcm_i2c_fifo_usage(bus)) { + if (bus->slv_wr_size <= 0) + break; + bus->slv_wr_ind = bus->slv_wr_ind & (bus->data->fifo_size - 1); + npcm_i2c_wr_byte(bus, bus->slv_wr_buf[bus->slv_wr_ind]); + bus->slv_wr_ind++; + bus->slv_wr_ind = bus->slv_wr_ind & (bus->data->fifo_size - 1); + bus->slv_wr_size--; + } +} + +static void npcm_i2c_read_fifo_slave(struct npcm_i2c *bus, u8 bytes_in_fifo) +{ + u8 data; + + if (!bus->slave) + return; + + while (bytes_in_fifo--) { + data = npcm_i2c_rd_byte(bus); + + bus->slv_rd_ind = bus->slv_rd_ind & (bus->data->fifo_size - 1); + bus->slv_rd_buf[bus->slv_rd_ind] = data; + bus->slv_rd_ind++; + + /* 1st byte is length in block protocol: */ + if (bus->slv_rd_ind == 1 && bus->read_block_use) + bus->slv_rd_size = data + bus->PEC_use + 1; + } +} + +static int npcm_i2c_slave_get_wr_buf(struct npcm_i2c *bus) +{ + int i; + u8 value; + int ind; + int ret = bus->slv_wr_ind; + + /* fill a cyclic buffer */ + for (i = 0; i < bus->data->fifo_size; i++) { + if (bus->slv_wr_size >= bus->data->fifo_size) + break; + if (bus->state == I2C_SLAVE_MATCH) { + i2c_slave_event(bus->slave, I2C_SLAVE_READ_REQUESTED, &value); + bus->state = I2C_OPER_STARTED; + } else { + i2c_slave_event(bus->slave, I2C_SLAVE_READ_PROCESSED, &value); + } + ind = (bus->slv_wr_ind + bus->slv_wr_size) & (bus->data->fifo_size - 1); + bus->slv_wr_buf[ind] = value; + bus->slv_wr_size++; + } + return bus->data->fifo_size - ret; +} + +static void npcm_i2c_slave_send_rd_buf(struct npcm_i2c *bus) +{ + int i; + + for (i = 0; i < bus->slv_rd_ind; i++) + i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_RECEIVED, + &bus->slv_rd_buf[i]); + /* + * once we send bytes up, need to reset the counter of the wr buf + * got data from master (new offset in device), ignore wr fifo: + */ + if (bus->slv_rd_ind) { + bus->slv_wr_size = 0; + bus->slv_wr_ind = 0; + } + + bus->slv_rd_ind = 0; + bus->slv_rd_size = bus->adap.quirks->max_read_len; + + npcm_i2c_clear_fifo_int(bus); + npcm_i2c_clear_rx_fifo(bus); +} + +static void npcm_i2c_slave_receive(struct npcm_i2c *bus, u16 nread, + u8 *read_data) +{ + bus->state = I2C_OPER_STARTED; + bus->operation = I2C_READ_OPER; + bus->slv_rd_size = nread; + bus->slv_rd_ind = 0; + + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); + iowrite8(bus->data->fifo_size, bus->reg + NPCM_I2CRXF_CTL); + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_clear_rx_fifo(bus); +} + +static void npcm_i2c_slave_xmit(struct npcm_i2c *bus, u16 nwrite, + u8 *write_data) +{ + if (nwrite == 0) + return; + + bus->operation = I2C_WRITE_OPER; + + /* get the next buffer */ + npcm_i2c_slave_get_wr_buf(bus); + npcm_i2c_write_fifo_slave(bus, nwrite); +} + +/* + * npcm_i2c_slave_wr_buf_sync: + * currently slave IF only supports single byte operations. + * in order to utilize the npcm HW FIFO, the driver will ask for 16 bytes + * at a time, pack them in buffer, and then transmit them all together + * to the FIFO and onward to the bus. + * NACK on read will be once reached to bus->adap->quirks->max_read_len. + * sending a NACK wherever the backend requests for it is not supported. + * the next two functions allow reading to local buffer before writing it all + * to the HW FIFO. + */ +static void npcm_i2c_slave_wr_buf_sync(struct npcm_i2c *bus) +{ + int left_in_fifo; + + left_in_fifo = bus->data->txf_sts_tx_bytes & + ioread8(bus->reg + NPCM_I2CTXF_STS); + + /* fifo already full: */ + if (left_in_fifo >= bus->data->fifo_size || + bus->slv_wr_size >= bus->data->fifo_size) + return; + + /* update the wr fifo index back to the untransmitted bytes: */ + bus->slv_wr_ind = bus->slv_wr_ind - left_in_fifo; + bus->slv_wr_size = bus->slv_wr_size + left_in_fifo; + + if (bus->slv_wr_ind < 0) + bus->slv_wr_ind += bus->data->fifo_size; +} + +static void npcm_i2c_slave_rd_wr(struct npcm_i2c *bus) +{ + if (NPCM_I2CST_XMIT & ioread8(bus->reg + NPCM_I2CST)) { + /* + * Slave got an address match with direction bit 1 so it should + * transmit data. Write till the master will NACK + */ + bus->operation = I2C_WRITE_OPER; + npcm_i2c_slave_xmit(bus, bus->adap.quirks->max_write_len, + bus->slv_wr_buf); + } else { + /* + * Slave got an address match with direction bit 0 so it should + * receive data. + * this module does not support saying no to bytes. + * it will always ACK. + */ + bus->operation = I2C_READ_OPER; + npcm_i2c_read_fifo_slave(bus, npcm_i2c_fifo_usage(bus)); + bus->stop_ind = I2C_SLAVE_RCV_IND; + npcm_i2c_slave_send_rd_buf(bus); + npcm_i2c_slave_receive(bus, bus->adap.quirks->max_read_len, + bus->slv_rd_buf); + } +} + +static irqreturn_t npcm_i2c_int_slave_handler(struct npcm_i2c *bus) +{ + u8 val; + irqreturn_t ret = IRQ_NONE; + u8 i2cst = ioread8(bus->reg + NPCM_I2CST); + + /* Slave: A NACK has occurred */ + if (NPCM_I2CST_NEGACK & i2cst) { + bus->stop_ind = I2C_NACK_IND; + npcm_i2c_slave_wr_buf_sync(bus); + if (bus->fifo_use) + /* clear the FIFO */ + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, + bus->reg + NPCM_I2CFIF_CTS); + + /* In slave write, NACK is OK, otherwise it is a problem */ + bus->stop_ind = I2C_NO_STATUS_IND; + bus->operation = I2C_NO_OPER; + bus->own_slave_addr = 0xFF; + + /* + * Slave has to wait for STOP to decide this is the end + * of the transaction. tx is not yet considered as done + */ + iowrite8(NPCM_I2CST_NEGACK, bus->reg + NPCM_I2CST); + + ret = IRQ_HANDLED; + } + + /* Slave mode: a Bus Error (BER) has been identified */ + if (NPCM_I2CST_BER & i2cst) { + /* + * Check whether bus arbitration or Start or Stop during data + * xfer bus arbitration problem should not result in recovery + */ + bus->stop_ind = I2C_BUS_ERR_IND; + + /* wait for bus busy before clear fifo */ + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS); + + bus->state = I2C_IDLE; + + /* + * in BER case we might get 2 interrupts: one for slave one for + * master ( for a channel which is master\slave switching) + */ + if (completion_done(&bus->cmd_complete) == false) { + bus->cmd_err = -EIO; + complete(&bus->cmd_complete); + } + bus->own_slave_addr = 0xFF; + iowrite8(NPCM_I2CST_BER, bus->reg + NPCM_I2CST); + ret = IRQ_HANDLED; + } + + /* A Slave Stop Condition has been identified */ + if (NPCM_I2CST_SLVSTP & i2cst) { + u8 bytes_in_fifo = npcm_i2c_fifo_usage(bus); + + bus->stop_ind = I2C_SLAVE_DONE_IND; + + if (bus->operation == I2C_READ_OPER) + npcm_i2c_read_fifo_slave(bus, bytes_in_fifo); + + /* if the buffer is empty nothing will be sent */ + npcm_i2c_slave_send_rd_buf(bus); + + /* Slave done transmitting or receiving */ + bus->stop_ind = I2C_NO_STATUS_IND; + + /* + * Note, just because we got here, it doesn't mean we through + * away the wr buffer. + * we keep it until the next received offset. + */ + bus->operation = I2C_NO_OPER; + bus->own_slave_addr = 0xFF; + i2c_slave_event(bus->slave, I2C_SLAVE_STOP, 0); + iowrite8(NPCM_I2CST_SLVSTP, bus->reg + NPCM_I2CST); + if (bus->fifo_use) { + npcm_i2c_clear_fifo_int(bus); + npcm_i2c_clear_rx_fifo(bus); + npcm_i2c_clear_tx_fifo(bus); + + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, + bus->reg + NPCM_I2CFIF_CTS); + } + bus->state = I2C_IDLE; + ret = IRQ_HANDLED; + } + + /* restart condition occurred and Rx-FIFO was not empty */ + if (bus->fifo_use && FIELD_GET(NPCM_I2CFIF_CTS_SLVRSTR, + ioread8(bus->reg + NPCM_I2CFIF_CTS))) { + bus->stop_ind = I2C_SLAVE_RESTART_IND; + bus->master_or_slave = I2C_SLAVE; + if (bus->operation == I2C_READ_OPER) + npcm_i2c_read_fifo_slave(bus, npcm_i2c_fifo_usage(bus)); + bus->operation = I2C_WRITE_OPER; + iowrite8(0, bus->reg + NPCM_I2CRXF_CTL); + val = NPCM_I2CFIF_CTS_CLR_FIFO | NPCM_I2CFIF_CTS_SLVRSTR | + NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(val, bus->reg + NPCM_I2CFIF_CTS); + npcm_i2c_slave_rd_wr(bus); + ret = IRQ_HANDLED; + } + + /* A Slave Address Match has been identified */ + if (NPCM_I2CST_NMATCH & i2cst) { + u8 info = 0; + + /* Address match automatically implies slave mode */ + bus->master_or_slave = I2C_SLAVE; + npcm_i2c_clear_fifo_int(bus); + npcm_i2c_clear_rx_fifo(bus); + npcm_i2c_clear_tx_fifo(bus); + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); + iowrite8(bus->data->fifo_size, bus->reg + NPCM_I2CRXF_CTL); + if (NPCM_I2CST_XMIT & i2cst) { + bus->operation = I2C_WRITE_OPER; + } else { + i2c_slave_event(bus->slave, I2C_SLAVE_WRITE_REQUESTED, + &info); + bus->operation = I2C_READ_OPER; + } + if (bus->own_slave_addr == 0xFF) { + /* Check which type of address match */ + val = ioread8(bus->reg + NPCM_I2CCST); + if (NPCM_I2CCST_MATCH & val) { + u16 addr; + enum i2c_addr eaddr; + u8 i2ccst2; + u8 i2ccst3; + + i2ccst3 = ioread8(bus->reg + NPCM_I2CCST3); + i2ccst2 = ioread8(bus->reg + NPCM_I2CCST2); + + /* + * the i2c module can response to 10 own SA. + * check which one was addressed by the master. + * respond to the first one. + */ + addr = ((i2ccst3 & 0x07) << 7) | + (i2ccst2 & 0x7F); + info = ffs(addr); + eaddr = (enum i2c_addr)info; + addr = npcm_i2c_get_slave_addr(bus, eaddr); + addr &= 0x7F; + bus->own_slave_addr = addr; + if (bus->PEC_mask & BIT(info)) + bus->PEC_use = true; + else + bus->PEC_use = false; + } else { + if (NPCM_I2CCST_GCMATCH & val) + bus->own_slave_addr = 0; + if (NPCM_I2CCST_ARPMATCH & val) + bus->own_slave_addr = 0x61; + } + } else { + /* + * Slave match can happen in two options: + * 1. Start, SA, read (slave read without further ado) + * 2. Start, SA, read, data, restart, SA, read, ... + * (slave read in fragmented mode) + * 3. Start, SA, write, data, restart, SA, read, .. + * (regular write-read mode) + */ + if ((bus->state == I2C_OPER_STARTED && + bus->operation == I2C_READ_OPER && + bus->stop_ind == I2C_SLAVE_XMIT_IND) || + bus->stop_ind == I2C_SLAVE_RCV_IND) { + /* slave tx after slave rx w/o STOP */ + bus->stop_ind = I2C_SLAVE_RESTART_IND; + } + } + + if (NPCM_I2CST_XMIT & i2cst) + bus->stop_ind = I2C_SLAVE_XMIT_IND; + else + bus->stop_ind = I2C_SLAVE_RCV_IND; + bus->state = I2C_SLAVE_MATCH; + npcm_i2c_slave_rd_wr(bus); + iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST); + ret = IRQ_HANDLED; + } + + /* Slave SDA status is set - tx or rx */ + if ((NPCM_I2CST_SDAST & i2cst) || + (bus->fifo_use && + (npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) { + npcm_i2c_slave_rd_wr(bus); + iowrite8(NPCM_I2CST_SDAST, bus->reg + NPCM_I2CST); + ret = IRQ_HANDLED; + } /* SDAST */ + + /* + * If irq is not one of the above, make sure EOB is disabled and all + * status bits are cleared. + */ + if (ret == IRQ_NONE) { + npcm_i2c_eob_int(bus, false); + npcm_i2c_clear_master_status(bus); + } + + return IRQ_HANDLED; +} + +static int npcm_i2c_reg_slave(struct i2c_client *client) +{ + unsigned long lock_flags; + struct npcm_i2c *bus = i2c_get_adapdata(client->adapter); + + bus->slave = client; + + if (!bus->slave) + return -EINVAL; + + if (client->flags & I2C_CLIENT_TEN) + return -EAFNOSUPPORT; + + spin_lock_irqsave(&bus->lock, lock_flags); + + npcm_i2c_init_params(bus); + bus->slv_rd_size = 0; + bus->slv_wr_size = 0; + bus->slv_rd_ind = 0; + bus->slv_wr_ind = 0; + if (client->flags & I2C_CLIENT_PEC) + bus->PEC_use = true; + + dev_info(bus->dev, "i2c%d register slave SA=0x%x, PEC=%d\n", bus->num, + client->addr, bus->PEC_use); + + npcm_i2c_slave_enable(bus, I2C_SLAVE_ADDR1, client->addr, true); + npcm_i2c_clear_fifo_int(bus); + npcm_i2c_clear_rx_fifo(bus); + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_slave_int_enable(bus, true); + + spin_unlock_irqrestore(&bus->lock, lock_flags); + return 0; +} + +static int npcm_i2c_unreg_slave(struct i2c_client *client) +{ + struct npcm_i2c *bus = client->adapter->algo_data; + unsigned long lock_flags; + + spin_lock_irqsave(&bus->lock, lock_flags); + if (!bus->slave) { + spin_unlock_irqrestore(&bus->lock, lock_flags); + return -EINVAL; + } + npcm_i2c_slave_int_enable(bus, false); + npcm_i2c_remove_slave_addr(bus, client->addr); + bus->slave = NULL; + spin_unlock_irqrestore(&bus->lock, lock_flags); + return 0; +} +#endif /* CONFIG_I2C_SLAVE */ + +static void npcm_i2c_master_fifo_read(struct npcm_i2c *bus) +{ + int rcount; + int fifo_bytes; + enum i2c_state_ind ind = I2C_MASTER_DONE_IND; + + fifo_bytes = npcm_i2c_fifo_usage(bus); + rcount = bus->rd_size - bus->rd_ind; + + /* + * In order not to change the RX_TRH during transaction (we found that + * this might be problematic if it takes too much time to read the FIFO) + * we read the data in the following way. If the number of bytes to + * read == FIFO Size + C (where C < FIFO Size)then first read C bytes + * and in the next int we read rest of the data. + */ + if (rcount < (2 * bus->data->fifo_size) && rcount > bus->data->fifo_size) + fifo_bytes = rcount - bus->data->fifo_size; + + if (rcount <= fifo_bytes) { + /* last bytes are about to be read - end of tx */ + bus->state = I2C_STOP_PENDING; + bus->stop_ind = ind; + npcm_i2c_eob_int(bus, true); + /* Stop should be set before reading last byte. */ + npcm_i2c_master_stop(bus); + npcm_i2c_read_fifo(bus, fifo_bytes); + } else { + npcm_i2c_read_fifo(bus, fifo_bytes); + rcount = bus->rd_size - bus->rd_ind; + npcm_i2c_set_fifo(bus, rcount, -1); + } +} + +static void npcm_i2c_irq_master_handler_write(struct npcm_i2c *bus) +{ + u16 wcount; + + if (bus->fifo_use) + npcm_i2c_clear_tx_fifo(bus); /* clear the TX fifo status bit */ + + /* Master write operation - last byte handling */ + if (bus->wr_ind == bus->wr_size) { + if (bus->fifo_use && npcm_i2c_fifo_usage(bus) > 0) + /* + * No more bytes to send (to add to the FIFO), + * however the FIFO is not empty yet. It is + * still in the middle of tx. Currently there's nothing + * to do except for waiting to the end of the tx + * We will get an int when the FIFO will get empty. + */ + return; + + if (bus->rd_size == 0) { + /* all bytes have been written, in wr only operation */ + npcm_i2c_eob_int(bus, true); + bus->state = I2C_STOP_PENDING; + bus->stop_ind = I2C_MASTER_DONE_IND; + npcm_i2c_master_stop(bus); + /* Clear SDA Status bit (by writing dummy byte) */ + npcm_i2c_wr_byte(bus, 0xFF); + + } else { + /* last write-byte written on previous int - restart */ + npcm_i2c_set_fifo(bus, bus->rd_size, -1); + /* Generate repeated start upon next write to SDA */ + npcm_i2c_master_start(bus); + + /* + * Receiving one byte only - stall after successful + * completion of send address byte. If we NACK here, and + * slave doesn't ACK the address, we might + * unintentionally NACK the next multi-byte read. + */ + if (bus->rd_size == 1) + npcm_i2c_stall_after_start(bus, true); + + /* Next int will occur on read */ + bus->operation = I2C_READ_OPER; + /* send the slave address in read direction */ + npcm_i2c_wr_byte(bus, bus->dest_addr | 0x1); + } + } else { + /* write next byte not last byte and not slave address */ + if (!bus->fifo_use || bus->wr_size == 1) { + npcm_i2c_wr_byte(bus, bus->wr_buf[bus->wr_ind++]); + } else { + wcount = bus->wr_size - bus->wr_ind; + npcm_i2c_set_fifo(bus, -1, wcount); + if (wcount) + npcm_i2c_write_to_fifo_master(bus, wcount); + } + } +} + +static void npcm_i2c_irq_master_handler_read(struct npcm_i2c *bus) +{ + u16 block_extra_bytes_size; + u8 data; + + /* added bytes to the packet: */ + block_extra_bytes_size = bus->read_block_use + bus->PEC_use; + + /* + * Perform master read, distinguishing between last byte and the rest of + * the bytes. The last byte should be read when the clock is stopped + */ + if (bus->rd_ind == 0) { /* first byte handling: */ + if (bus->read_block_use) { + /* first byte in block protocol is the size: */ + data = npcm_i2c_rd_byte(bus); + data = clamp_val(data, 1, I2C_SMBUS_BLOCK_MAX); + bus->rd_size = data + block_extra_bytes_size; + bus->rd_buf[bus->rd_ind++] = data; + + /* clear RX FIFO interrupt status: */ + if (bus->fifo_use) { + data = ioread8(bus->reg + NPCM_I2CFIF_CTS); + data = data | NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(data, bus->reg + NPCM_I2CFIF_CTS); + } + + npcm_i2c_set_fifo(bus, bus->rd_size - 1, -1); + npcm_i2c_stall_after_start(bus, false); + } else { + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_master_fifo_read(bus); + } + } else { + if (bus->rd_size == block_extra_bytes_size && + bus->read_block_use) { + bus->state = I2C_STOP_PENDING; + bus->stop_ind = I2C_BLOCK_BYTES_ERR_IND; + bus->cmd_err = -EIO; + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + npcm_i2c_read_fifo(bus, npcm_i2c_fifo_usage(bus)); + } else { + npcm_i2c_master_fifo_read(bus); + } + } +} + +static void npcm_i2c_irq_handle_nmatch(struct npcm_i2c *bus) +{ + iowrite8(NPCM_I2CST_NMATCH, bus->reg + NPCM_I2CST); + npcm_i2c_nack(bus); + bus->stop_ind = I2C_BUS_ERR_IND; + npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus)); +} + +/* A NACK has occurred */ +static void npcm_i2c_irq_handle_nack(struct npcm_i2c *bus) +{ + u8 val; + + if (bus->nack_cnt < ULLONG_MAX) + bus->nack_cnt++; + + if (bus->fifo_use) { + /* + * if there are still untransmitted bytes in TX FIFO + * reduce them from wr_ind + */ + if (bus->operation == I2C_WRITE_OPER) + bus->wr_ind -= npcm_i2c_fifo_usage(bus); + + /* clear the FIFO */ + iowrite8(NPCM_I2CFIF_CTS_CLR_FIFO, bus->reg + NPCM_I2CFIF_CTS); + } + + /* In master write operation, got unexpected NACK */ + bus->stop_ind = I2C_NACK_IND; + /* Only current master is allowed to issue Stop Condition */ + if (npcm_i2c_is_master(bus)) { + /* stopping in the middle */ + npcm_i2c_eob_int(bus, false); + npcm_i2c_master_stop(bus); + + /* Clear SDA Status bit (by reading dummy byte) */ + npcm_i2c_rd_byte(bus); + + /* + * The bus is released from stall only after the SW clears + * NEGACK bit. Then a Stop condition is sent. + */ + npcm_i2c_clear_master_status(bus); + readx_poll_timeout_atomic(ioread8, bus->reg + NPCM_I2CCST, val, + !(val & NPCM_I2CCST_BUSY), 10, 200); + /* Verify no status bits are still set after bus is released */ + npcm_i2c_clear_master_status(bus); + } + bus->state = I2C_IDLE; + + /* + * In Master mode, NACK should be cleared only after STOP. + * In such case, the bus is released from stall only after the + * software clears NACK bit. Then a Stop condition is sent. + */ + npcm_i2c_callback(bus, bus->stop_ind, bus->wr_ind); +} + + /* Master mode: a Bus Error has been identified */ +static void npcm_i2c_irq_handle_ber(struct npcm_i2c *bus) +{ + if (bus->ber_cnt < ULLONG_MAX) + bus->ber_cnt++; + bus->stop_ind = I2C_BUS_ERR_IND; + if (npcm_i2c_is_master(bus)) { + npcm_i2c_master_abort(bus); + } else { + npcm_i2c_clear_master_status(bus); + + /* Clear BB (BUS BUSY) bit */ + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + + bus->cmd_err = -EAGAIN; + npcm_i2c_callback(bus, bus->stop_ind, npcm_i2c_get_index(bus)); + } + bus->state = I2C_IDLE; +} + + /* EOB: a master End Of Busy (meaning STOP completed) */ +static void npcm_i2c_irq_handle_eob(struct npcm_i2c *bus) +{ + npcm_i2c_eob_int(bus, false); + bus->state = I2C_IDLE; + npcm_i2c_callback(bus, bus->stop_ind, bus->rd_ind); +} + +/* Address sent and requested stall occurred (Master mode) */ +static void npcm_i2c_irq_handle_stall_after_start(struct npcm_i2c *bus) +{ + if (npcm_i2c_is_quick(bus)) { + bus->state = I2C_STOP_PENDING; + bus->stop_ind = I2C_MASTER_DONE_IND; + npcm_i2c_eob_int(bus, true); + npcm_i2c_master_stop(bus); + } else if ((bus->rd_size == 1) && !bus->read_block_use) { + /* + * Receiving one byte only - set NACK after ensuring + * slave ACKed the address byte. + */ + npcm_i2c_nack(bus); + } + + /* Reset stall-after-address-byte */ + npcm_i2c_stall_after_start(bus, false); + + /* Clear stall only after setting STOP */ + iowrite8(NPCM_I2CST_STASTR, bus->reg + NPCM_I2CST); +} + +/* SDA status is set - TX or RX, master */ +static void npcm_i2c_irq_handle_sda(struct npcm_i2c *bus, u8 i2cst) +{ + u8 fif_cts; + + if (!npcm_i2c_is_master(bus)) + return; + + if (bus->state == I2C_IDLE) { + bus->stop_ind = I2C_WAKE_UP_IND; + + if (npcm_i2c_is_quick(bus) || bus->read_block_use) + /* + * Need to stall after successful + * completion of sending address byte + */ + npcm_i2c_stall_after_start(bus, true); + else + npcm_i2c_stall_after_start(bus, false); + + /* + * Receiving one byte only - stall after successful completion + * of sending address byte If we NACK here, and slave doesn't + * ACK the address, we might unintentionally NACK the next + * multi-byte read + */ + if (bus->wr_size == 0 && bus->rd_size == 1) + npcm_i2c_stall_after_start(bus, true); + + /* Initiate I2C master tx */ + + /* select bank 1 for FIFO regs */ + npcm_i2c_select_bank(bus, I2C_BANK_1); + + fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS); + fif_cts = fif_cts & ~NPCM_I2CFIF_CTS_SLVRSTR; + + /* clear FIFO and relevant status bits. */ + fif_cts = fif_cts | NPCM_I2CFIF_CTS_CLR_FIFO; + iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS); + + /* re-enable */ + fif_cts = fif_cts | NPCM_I2CFIF_CTS_RXF_TXE; + iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS); + + /* + * Configure the FIFO threshold: + * according to the needed # of bytes to read. + * Note: due to HW limitation can't config the rx fifo before it + * got and ACK on the restart. LAST bit will not be reset unless + * RX completed. It will stay set on the next tx. + */ + if (bus->wr_size) + npcm_i2c_set_fifo(bus, -1, bus->wr_size); + else + npcm_i2c_set_fifo(bus, bus->rd_size, -1); + + bus->state = I2C_OPER_STARTED; + + if (npcm_i2c_is_quick(bus) || bus->wr_size) + npcm_i2c_wr_byte(bus, bus->dest_addr); + else + npcm_i2c_wr_byte(bus, bus->dest_addr | BIT(0)); + /* SDA interrupt, after start\restart */ + } else { + if (NPCM_I2CST_XMIT & i2cst) { + bus->operation = I2C_WRITE_OPER; + npcm_i2c_irq_master_handler_write(bus); + } else { + bus->operation = I2C_READ_OPER; + npcm_i2c_irq_master_handler_read(bus); + } + } +} + +static int npcm_i2c_int_master_handler(struct npcm_i2c *bus) +{ + u8 i2cst; + int ret = -EIO; + + i2cst = ioread8(bus->reg + NPCM_I2CST); + + if (FIELD_GET(NPCM_I2CST_NMATCH, i2cst)) { + npcm_i2c_irq_handle_nmatch(bus); + return 0; + } + /* A NACK has occurred */ + if (FIELD_GET(NPCM_I2CST_NEGACK, i2cst)) { + npcm_i2c_irq_handle_nack(bus); + return 0; + } + + /* Master mode: a Bus Error has been identified */ + if (FIELD_GET(NPCM_I2CST_BER, i2cst)) { + npcm_i2c_irq_handle_ber(bus); + return 0; + } + + /* EOB: a master End Of Busy (meaning STOP completed) */ + if ((FIELD_GET(NPCM_I2CCTL1_EOBINTE, + ioread8(bus->reg + NPCM_I2CCTL1)) == 1) && + (FIELD_GET(NPCM_I2CCST3_EO_BUSY, + ioread8(bus->reg + NPCM_I2CCST3)))) { + npcm_i2c_irq_handle_eob(bus); + return 0; + } + + /* Address sent and requested stall occurred (Master mode) */ + if (FIELD_GET(NPCM_I2CST_STASTR, i2cst)) { + npcm_i2c_irq_handle_stall_after_start(bus); + ret = 0; + } + + /* SDA status is set - TX or RX, master */ + if (FIELD_GET(NPCM_I2CST_SDAST, i2cst) || + (bus->fifo_use && + (npcm_i2c_tx_fifo_empty(bus) || npcm_i2c_rx_fifo_full(bus)))) { + npcm_i2c_irq_handle_sda(bus, i2cst); + ret = 0; + } + + return ret; +} + +/* recovery using TGCLK functionality of the module */ +static int npcm_i2c_recovery_tgclk(struct i2c_adapter *_adap) +{ + u8 val; + u8 fif_cts; + bool done = false; + int status = -ENOTRECOVERABLE; + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + /* Allow 3 bytes (27 toggles) to be read from the slave: */ + int iter = 27; + + if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1)) { + dev_dbg(bus->dev, "bus%d-0x%x recovery skipped, bus not stuck", + bus->num, bus->dest_addr); + npcm_i2c_reset(bus); + return 0; + } + + npcm_i2c_int_enable(bus, false); + npcm_i2c_disable(bus); + npcm_i2c_enable(bus); + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + npcm_i2c_clear_tx_fifo(bus); + npcm_i2c_clear_rx_fifo(bus); + iowrite8(0, bus->reg + NPCM_I2CRXF_CTL); + iowrite8(0, bus->reg + NPCM_I2CTXF_CTL); + npcm_i2c_stall_after_start(bus, false); + + /* select bank 1 for FIFO regs */ + npcm_i2c_select_bank(bus, I2C_BANK_1); + + /* clear FIFO and relevant status bits. */ + fif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS); + fif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR; + fif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO; + iowrite8(fif_cts, bus->reg + NPCM_I2CFIF_CTS); + npcm_i2c_set_fifo(bus, -1, 0); + + /* Repeat the following sequence until SDA is released */ + do { + /* Issue a single SCL toggle */ + iowrite8(NPCM_I2CCST_TGSCL, bus->reg + NPCM_I2CCST); + usleep_range(20, 30); + /* If SDA line is inactive (high), stop */ + if (npcm_i2c_get_SDA(_adap)) { + done = true; + status = 0; + } + } while (!done && iter--); + + /* If SDA line is released: send start-addr-stop, to re-sync. */ + if (npcm_i2c_get_SDA(_adap)) { + /* Send an address byte in write direction: */ + npcm_i2c_wr_byte(bus, bus->dest_addr); + npcm_i2c_master_start(bus); + /* Wait until START condition is sent */ + status = readx_poll_timeout(npcm_i2c_get_SCL, _adap, val, !val, + 20, 200); + /* If START condition was sent */ + if (npcm_i2c_is_master(bus) > 0) { + usleep_range(20, 30); + npcm_i2c_master_stop(bus); + usleep_range(200, 500); + } + } + npcm_i2c_reset(bus); + npcm_i2c_int_enable(bus, true); + + if ((npcm_i2c_get_SDA(_adap) == 1) && (npcm_i2c_get_SCL(_adap) == 1)) + status = 0; + else + status = -ENOTRECOVERABLE; + if (status) { + if (bus->rec_fail_cnt < ULLONG_MAX) + bus->rec_fail_cnt++; + } else { + if (bus->rec_succ_cnt < ULLONG_MAX) + bus->rec_succ_cnt++; + } + return status; +} + +/* recovery using bit banging functionality of the module */ +static void npcm_i2c_recovery_init(struct i2c_adapter *_adap) +{ + struct npcm_i2c *bus = container_of(_adap, struct npcm_i2c, adap); + struct i2c_bus_recovery_info *rinfo = &bus->rinfo; + + rinfo->recover_bus = npcm_i2c_recovery_tgclk; + + /* + * npcm i2c HW allows direct reading of SCL and SDA. + * However, it does not support setting SCL and SDA directly. + * The recovery function can toggle SCL when SDA is low (but not set) + * Getter functions used internally, and can be used externally. + */ + rinfo->get_scl = npcm_i2c_get_SCL; + rinfo->get_sda = npcm_i2c_get_SDA; + _adap->bus_recovery_info = rinfo; +} + +/* SCLFRQ min/max field values */ +#define SCLFRQ_MIN 10 +#define SCLFRQ_MAX 511 +#define clk_coef(freq, mul) DIV_ROUND_UP((freq) * (mul), 1000000) + +/* + * npcm_i2c_init_clk: init HW timing parameters. + * NPCM7XX i2c module timing parameters are dependent on module core clk (APB) + * and bus frequency. + * 100kHz bus requires tSCL = 4 * SCLFRQ * tCLK. LT and HT are symmetric. + * 400kHz bus requires asymmetric HT and LT. A different equation is recommended + * by the HW designer, given core clock range (equations in comments below). + * + */ +static int npcm_i2c_init_clk(struct npcm_i2c *bus, u32 bus_freq_hz) +{ + u32 k1 = 0; + u32 k2 = 0; + u8 dbnct = 0; + u32 sclfrq = 0; + u8 hldt = 7; + u8 fast_mode = 0; + u32 src_clk_khz; + u32 bus_freq_khz; + + src_clk_khz = bus->apb_clk / 1000; + bus_freq_khz = bus_freq_hz / 1000; + bus->bus_freq = bus_freq_hz; + + /* 100KHz and below: */ + if (bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ) { + sclfrq = src_clk_khz / (bus_freq_khz * 4); + + if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX) + return -EDOM; + + if (src_clk_khz >= 40000) + hldt = 17; + else if (src_clk_khz >= 12500) + hldt = 15; + else + hldt = 7; + } + + /* 400KHz: */ + else if (bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ) { + sclfrq = 0; + fast_mode = I2CCTL3_400K_MODE; + + if (src_clk_khz < 7500) + /* 400KHZ cannot be supported for core clock < 7.5MHz */ + return -EDOM; + + else if (src_clk_khz >= 50000) { + k1 = 80; + k2 = 48; + hldt = 12; + dbnct = 7; + } + + /* Master or Slave with frequency > 25MHz */ + else if (src_clk_khz > 25000) { + hldt = clk_coef(src_clk_khz, 300) + 7; + k1 = clk_coef(src_clk_khz, 1600); + k2 = clk_coef(src_clk_khz, 900); + } + } + + /* 1MHz: */ + else if (bus_freq_hz <= I2C_MAX_FAST_MODE_PLUS_FREQ) { + sclfrq = 0; + fast_mode = I2CCTL3_400K_MODE; + + /* 1MHZ cannot be supported for core clock < 24 MHz */ + if (src_clk_khz < 24000) + return -EDOM; + + k1 = clk_coef(src_clk_khz, 620); + k2 = clk_coef(src_clk_khz, 380); + + /* Core clk > 40 MHz */ + if (src_clk_khz > 40000) { + /* + * Set HLDT: + * SDA hold time: (HLDT-7) * T(CLK) >= 120 + * HLDT = 120/T(CLK) + 7 = 120 * FREQ(CLK) + 7 + */ + hldt = clk_coef(src_clk_khz, 120) + 7; + } else { + hldt = 7; + dbnct = 2; + } + } + + /* Frequency larger than 1 MHz is not supported */ + else + return -EINVAL; + + if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) { + k1 = round_up(k1, 2); + k2 = round_up(k2 + 1, 2); + if (k1 < SCLFRQ_MIN || k1 > SCLFRQ_MAX || + k2 < SCLFRQ_MIN || k2 > SCLFRQ_MAX) + return -EDOM; + } + + /* write sclfrq value. bits [6:0] are in I2CCTL2 reg */ + iowrite8(FIELD_PREP(I2CCTL2_SCLFRQ6_0, sclfrq & 0x7F), + bus->reg + NPCM_I2CCTL2); + + /* bits [8:7] are in I2CCTL3 reg */ + iowrite8(fast_mode | FIELD_PREP(I2CCTL3_SCLFRQ8_7, (sclfrq >> 7) & 0x3), + bus->reg + NPCM_I2CCTL3); + + /* Select Bank 0 to access NPCM_I2CCTL4/NPCM_I2CCTL5 */ + npcm_i2c_select_bank(bus, I2C_BANK_0); + + if (bus_freq_hz >= I2C_MAX_FAST_MODE_FREQ) { + /* + * Set SCL Low/High Time: + * k1 = 2 * SCLLT7-0 -> Low Time = k1 / 2 + * k2 = 2 * SCLLT7-0 -> High Time = k2 / 2 + */ + iowrite8(k1 / 2, bus->reg + NPCM_I2CSCLLT); + iowrite8(k2 / 2, bus->reg + NPCM_I2CSCLHT); + + iowrite8(dbnct, bus->reg + NPCM_I2CCTL5); + } + + iowrite8(hldt, bus->reg + NPCM_I2CCTL4); + + /* Return to Bank 1, and stay there by default: */ + npcm_i2c_select_bank(bus, I2C_BANK_1); + + return 0; +} + +static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode, + u32 bus_freq_hz) +{ + u8 val; + int ret; + + /* Check whether module already enabled or frequency is out of bounds */ + if ((bus->state != I2C_DISABLE && bus->state != I2C_IDLE) || + bus_freq_hz < I2C_FREQ_MIN_HZ || bus_freq_hz > I2C_FREQ_MAX_HZ) + return -EINVAL; + + npcm_i2c_int_enable(bus, false); + npcm_i2c_disable(bus); + + /* Configure FIFO mode : */ + if (FIELD_GET(I2C_VER_FIFO_EN, ioread8(bus->reg + I2C_VER))) { + bus->fifo_use = true; + npcm_i2c_select_bank(bus, I2C_BANK_0); + val = ioread8(bus->reg + NPCM_I2CFIF_CTL); + val |= NPCM_I2CFIF_CTL_FIFO_EN; + iowrite8(val, bus->reg + NPCM_I2CFIF_CTL); + npcm_i2c_select_bank(bus, I2C_BANK_1); + } else { + bus->fifo_use = false; + } + + /* Configure I2C module clock frequency */ + ret = npcm_i2c_init_clk(bus, bus_freq_hz); + if (ret) { + dev_err(bus->dev, "npcm_i2c_init_clk failed\n"); + return ret; + } + + /* Enable module (before configuring CTL1) */ + npcm_i2c_enable(bus); + bus->state = I2C_IDLE; + val = ioread8(bus->reg + NPCM_I2CCTL1); + val = (val | NPCM_I2CCTL1_NMINTE) & ~NPCM_I2CCTL1_RWS; + iowrite8(val, bus->reg + NPCM_I2CCTL1); + + npcm_i2c_reset(bus); + + /* Check HW is OK: SDA and SCL should be high at this point. */ + if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) { + dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num); + dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap), + npcm_i2c_get_SCL(&bus->adap)); + return -ENXIO; + } + + npcm_i2c_int_enable(bus, true); + return 0; +} + +static int __npcm_i2c_init(struct npcm_i2c *bus, struct platform_device *pdev) +{ + u32 clk_freq_hz; + int ret; + + /* Initialize the internal data structures */ + bus->state = I2C_DISABLE; + bus->master_or_slave = I2C_SLAVE; + bus->int_time_stamp = 0; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + bus->slave = NULL; +#endif + + ret = device_property_read_u32(&pdev->dev, "clock-frequency", + &clk_freq_hz); + if (ret) { + dev_info(&pdev->dev, "Could not read clock-frequency property"); + clk_freq_hz = I2C_MAX_STANDARD_MODE_FREQ; + } + + ret = npcm_i2c_init_module(bus, I2C_MASTER, clk_freq_hz); + if (ret) { + dev_err(&pdev->dev, "npcm_i2c_init_module failed\n"); + return ret; + } + + return 0; +} + +static irqreturn_t npcm_i2c_bus_irq(int irq, void *dev_id) +{ + struct npcm_i2c *bus = dev_id; + + if (npcm_i2c_is_master(bus)) + bus->master_or_slave = I2C_MASTER; + + if (bus->master_or_slave == I2C_MASTER) { + bus->int_time_stamp = jiffies; + if (!npcm_i2c_int_master_handler(bus)) + return IRQ_HANDLED; + } +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (bus->slave) { + bus->master_or_slave = I2C_SLAVE; + if (npcm_i2c_int_slave_handler(bus)) + return IRQ_HANDLED; + } +#endif + /* Clear status bits for spurious interrupts */ + npcm_i2c_clear_master_status(bus); + + return IRQ_HANDLED; +} + +static bool npcm_i2c_master_start_xmit(struct npcm_i2c *bus, + u8 slave_addr, u16 nwrite, u16 nread, + u8 *write_data, u8 *read_data, + bool use_PEC, bool use_read_block) +{ + if (bus->state != I2C_IDLE) { + bus->cmd_err = -EBUSY; + return false; + } + bus->dest_addr = slave_addr << 1; + bus->wr_buf = write_data; + bus->wr_size = nwrite; + bus->wr_ind = 0; + bus->rd_buf = read_data; + bus->rd_size = nread; + bus->rd_ind = 0; + bus->PEC_use = 0; + + /* for tx PEC is appended to buffer from i2c IF. PEC flag is ignored */ + if (nread) + bus->PEC_use = use_PEC; + + bus->read_block_use = use_read_block; + if (nread && !nwrite) + bus->operation = I2C_READ_OPER; + else + bus->operation = I2C_WRITE_OPER; + if (bus->fifo_use) { + u8 i2cfif_cts; + + npcm_i2c_select_bank(bus, I2C_BANK_1); + /* clear FIFO and relevant status bits. */ + i2cfif_cts = ioread8(bus->reg + NPCM_I2CFIF_CTS); + i2cfif_cts &= ~NPCM_I2CFIF_CTS_SLVRSTR; + i2cfif_cts |= NPCM_I2CFIF_CTS_CLR_FIFO; + iowrite8(i2cfif_cts, bus->reg + NPCM_I2CFIF_CTS); + } + + bus->state = I2C_IDLE; + npcm_i2c_stall_after_start(bus, true); + npcm_i2c_master_start(bus); + return true; +} + +static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct npcm_i2c *bus = container_of(adap, struct npcm_i2c, adap); + struct i2c_msg *msg0, *msg1; + unsigned long time_left, flags; + u16 nwrite, nread; + u8 *write_data, *read_data; + u8 slave_addr; + unsigned long timeout; + bool read_block = false; + bool read_PEC = false; + u8 bus_busy; + unsigned long timeout_usec; + + if (bus->state == I2C_DISABLE) { + dev_err(bus->dev, "I2C%d module is disabled", bus->num); + return -EINVAL; + } + + msg0 = &msgs[0]; + slave_addr = msg0->addr; + if (msg0->flags & I2C_M_RD) { /* read */ + nwrite = 0; + write_data = NULL; + read_data = msg0->buf; + if (msg0->flags & I2C_M_RECV_LEN) { + nread = 1; + read_block = true; + if (msg0->flags & I2C_CLIENT_PEC) + read_PEC = true; + } else { + nread = msg0->len; + } + } else { /* write */ + nwrite = msg0->len; + write_data = msg0->buf; + nread = 0; + read_data = NULL; + if (num == 2) { + msg1 = &msgs[1]; + read_data = msg1->buf; + if (msg1->flags & I2C_M_RECV_LEN) { + nread = 1; + read_block = true; + if (msg1->flags & I2C_CLIENT_PEC) + read_PEC = true; + } else { + nread = msg1->len; + read_block = false; + } + } + } + + /* + * Adaptive TimeOut: estimated time in usec + 100% margin: + * 2: double the timeout for clock stretching case + * 9: bits per transaction (including the ack/nack) + */ + timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite); + timeout = max_t(unsigned long, bus->adap.timeout, usecs_to_jiffies(timeout_usec)); + if (nwrite >= 32 * 1024 || nread >= 32 * 1024) { + dev_err(bus->dev, "i2c%d buffer too big\n", bus->num); + return -EINVAL; + } + + time_left = jiffies + timeout + 1; + do { + /* + * we must clear slave address immediately when the bus is not + * busy, so we spinlock it, but we don't keep the lock for the + * entire while since it is too long. + */ + spin_lock_irqsave(&bus->lock, flags); + bus_busy = ioread8(bus->reg + NPCM_I2CCST) & NPCM_I2CCST_BB; +#if IS_ENABLED(CONFIG_I2C_SLAVE) + if (!bus_busy && bus->slave) + iowrite8((bus->slave->addr & 0x7F), + bus->reg + NPCM_I2CADDR1); +#endif + spin_unlock_irqrestore(&bus->lock, flags); + + } while (time_is_after_jiffies(time_left) && bus_busy); + + if (bus_busy) { + iowrite8(NPCM_I2CCST_BB, bus->reg + NPCM_I2CCST); + npcm_i2c_reset(bus); + i2c_recover_bus(adap); + return -EAGAIN; + } + + npcm_i2c_init_params(bus); + bus->dest_addr = slave_addr; + bus->msgs = msgs; + bus->msgs_num = num; + bus->cmd_err = 0; + bus->read_block_use = read_block; + + reinit_completion(&bus->cmd_complete); + + npcm_i2c_int_enable(bus, true); + + if (npcm_i2c_master_start_xmit(bus, slave_addr, nwrite, nread, + write_data, read_data, read_PEC, + read_block)) { + time_left = wait_for_completion_timeout(&bus->cmd_complete, + timeout); + + if (time_left == 0) { + if (bus->timeout_cnt < ULLONG_MAX) + bus->timeout_cnt++; + if (bus->master_or_slave == I2C_MASTER) { + i2c_recover_bus(adap); + bus->cmd_err = -EIO; + bus->state = I2C_IDLE; + } + } + } + + /* if there was BER, check if need to recover the bus: */ + if (bus->cmd_err == -EAGAIN) + bus->cmd_err = i2c_recover_bus(adap); + + /* + * After any type of error, check if LAST bit is still set, + * due to a HW issue. + * It cannot be cleared without resetting the module. + */ + else if (bus->cmd_err && + (bus->data->rxf_ctl_last_pec & ioread8(bus->reg + NPCM_I2CRXF_CTL))) + npcm_i2c_reset(bus); + + /* After any xfer, successful or not, stall and EOB must be disabled */ + npcm_i2c_stall_after_start(bus, false); + npcm_i2c_eob_int(bus, false); + +#if IS_ENABLED(CONFIG_I2C_SLAVE) + /* reenable slave if it was enabled */ + if (bus->slave) + iowrite8((bus->slave->addr & 0x7F) | NPCM_I2CADDR_SAEN, + bus->reg + NPCM_I2CADDR1); +#else + npcm_i2c_int_enable(bus, false); +#endif + return bus->cmd_err; +} + +static u32 npcm_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | + I2C_FUNC_SMBUS_EMUL | + I2C_FUNC_SMBUS_BLOCK_DATA | + I2C_FUNC_SMBUS_PEC | + I2C_FUNC_SLAVE; +} + +static const struct i2c_adapter_quirks npcm_i2c_quirks = { + .max_read_len = 32768, + .max_write_len = 32768, + .flags = I2C_AQ_COMB_WRITE_THEN_READ, +}; + +static const struct i2c_algorithm npcm_i2c_algo = { + .master_xfer = npcm_i2c_master_xfer, + .functionality = npcm_i2c_functionality, +#if IS_ENABLED(CONFIG_I2C_SLAVE) + .reg_slave = npcm_i2c_reg_slave, + .unreg_slave = npcm_i2c_unreg_slave, +#endif +}; + +/* i2c debugfs directory: used to keep health monitor of i2c devices */ +static struct dentry *npcm_i2c_debugfs_dir; + +static void npcm_i2c_init_debugfs(struct platform_device *pdev, + struct npcm_i2c *bus) +{ + struct dentry *d; + + if (!npcm_i2c_debugfs_dir) + return; + d = debugfs_create_dir(dev_name(&pdev->dev), npcm_i2c_debugfs_dir); + if (IS_ERR_OR_NULL(d)) + return; + debugfs_create_u64("ber_cnt", 0444, d, &bus->ber_cnt); + debugfs_create_u64("nack_cnt", 0444, d, &bus->nack_cnt); + debugfs_create_u64("rec_succ_cnt", 0444, d, &bus->rec_succ_cnt); + debugfs_create_u64("rec_fail_cnt", 0444, d, &bus->rec_fail_cnt); + debugfs_create_u64("timeout_cnt", 0444, d, &bus->timeout_cnt); + debugfs_create_u64("tx_complete_cnt", 0444, d, &bus->tx_complete_cnt); + + bus->debugfs = d; +} + +static int npcm_i2c_probe_bus(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + static struct regmap *gcr_regmap; + struct device *dev = &pdev->dev; + struct i2c_adapter *adap; + struct npcm_i2c *bus; + struct clk *i2c_clk; + int irq; + int ret; + + bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); + if (!bus) + return -ENOMEM; + + bus->dev = &pdev->dev; + + bus->data = of_device_get_match_data(dev); + if (!bus->data) { + dev_err(dev, "OF data missing\n"); + return -EINVAL; + } + + bus->num = of_alias_get_id(pdev->dev.of_node, "i2c"); + /* core clk must be acquired to calculate module timing settings */ + i2c_clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(i2c_clk)) + return PTR_ERR(i2c_clk); + bus->apb_clk = clk_get_rate(i2c_clk); + + gcr_regmap = syscon_regmap_lookup_by_phandle(np, "nuvoton,sys-mgr"); + if (IS_ERR(gcr_regmap)) + gcr_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr"); + + if (IS_ERR(gcr_regmap)) + return PTR_ERR(gcr_regmap); + regmap_write(gcr_regmap, NPCM_I2CSEGCTL, bus->data->segctl_init_val); + + bus->reg = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(bus->reg)) + return PTR_ERR(bus->reg); + + spin_lock_init(&bus->lock); + init_completion(&bus->cmd_complete); + + adap = &bus->adap; + adap->owner = THIS_MODULE; + adap->retries = 3; + adap->timeout = msecs_to_jiffies(35); + adap->algo = &npcm_i2c_algo; + adap->quirks = &npcm_i2c_quirks; + adap->algo_data = bus; + adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; + adap->nr = pdev->id; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + ret = devm_request_irq(bus->dev, irq, npcm_i2c_bus_irq, 0, + dev_name(bus->dev), bus); + if (ret) + return ret; + + ret = __npcm_i2c_init(bus, pdev); + if (ret) + return ret; + + npcm_i2c_recovery_init(adap); + + i2c_set_adapdata(adap, bus); + + snprintf(bus->adap.name, sizeof(bus->adap.name), "npcm_i2c_%d", + bus->num); + ret = i2c_add_numbered_adapter(&bus->adap); + if (ret) + return ret; + + platform_set_drvdata(pdev, bus); + npcm_i2c_init_debugfs(pdev, bus); + return 0; +} + +static void npcm_i2c_remove_bus(struct platform_device *pdev) +{ + unsigned long lock_flags; + struct npcm_i2c *bus = platform_get_drvdata(pdev); + + debugfs_remove_recursive(bus->debugfs); + spin_lock_irqsave(&bus->lock, lock_flags); + npcm_i2c_disable(bus); + spin_unlock_irqrestore(&bus->lock, lock_flags); + i2c_del_adapter(&bus->adap); +} + +static const struct of_device_id npcm_i2c_bus_of_table[] = { + { .compatible = "nuvoton,npcm750-i2c", .data = &npxm7xx_i2c_data }, + { .compatible = "nuvoton,npcm845-i2c", .data = &npxm8xx_i2c_data }, + {} +}; +MODULE_DEVICE_TABLE(of, npcm_i2c_bus_of_table); + +static struct platform_driver npcm_i2c_bus_driver = { + .probe = npcm_i2c_probe_bus, + .remove_new = npcm_i2c_remove_bus, + .driver = { + .name = "nuvoton-i2c", + .of_match_table = npcm_i2c_bus_of_table, + } +}; + +static int __init npcm_i2c_init(void) +{ + int ret; + + npcm_i2c_debugfs_dir = debugfs_create_dir("npcm_i2c", NULL); + + ret = platform_driver_register(&npcm_i2c_bus_driver); + if (ret) { + debugfs_remove_recursive(npcm_i2c_debugfs_dir); + return ret; + } + + return 0; +} +module_init(npcm_i2c_init); + +static void __exit npcm_i2c_exit(void) +{ + platform_driver_unregister(&npcm_i2c_bus_driver); + debugfs_remove_recursive(npcm_i2c_debugfs_dir); +} +module_exit(npcm_i2c_exit); + +MODULE_AUTHOR("Avi Fishman <avi.fishman@gmail.com>"); +MODULE_AUTHOR("Tali Perry <tali.perry@nuvoton.com>"); +MODULE_AUTHOR("Tyrone Ting <kfting@nuvoton.com>"); +MODULE_DESCRIPTION("Nuvoton I2C Bus Driver"); +MODULE_LICENSE("GPL v2"); |