diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-bcm-kona.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-bcm-kona.c | 887 |
1 files changed, 887 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-bcm-kona.c b/drivers/i2c/busses/i2c-bcm-kona.c new file mode 100644 index 0000000000..a57088ec2b --- /dev/null +++ b/drivers/i2c/busses/i2c-bcm-kona.c @@ -0,0 +1,887 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2013 Broadcom Corporation + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/slab.h> + +/* Hardware register offsets and field defintions */ +#define CS_OFFSET 0x00000020 +#define CS_ACK_SHIFT 3 +#define CS_ACK_MASK 0x00000008 +#define CS_ACK_CMD_GEN_START 0x00000000 +#define CS_ACK_CMD_GEN_RESTART 0x00000001 +#define CS_CMD_SHIFT 1 +#define CS_CMD_CMD_NO_ACTION 0x00000000 +#define CS_CMD_CMD_START_RESTART 0x00000001 +#define CS_CMD_CMD_STOP 0x00000002 +#define CS_EN_SHIFT 0 +#define CS_EN_CMD_ENABLE_BSC 0x00000001 + +#define TIM_OFFSET 0x00000024 +#define TIM_PRESCALE_SHIFT 6 +#define TIM_P_SHIFT 3 +#define TIM_NO_DIV_SHIFT 2 +#define TIM_DIV_SHIFT 0 + +#define DAT_OFFSET 0x00000028 + +#define TOUT_OFFSET 0x0000002c + +#define TXFCR_OFFSET 0x0000003c +#define TXFCR_FIFO_FLUSH_MASK 0x00000080 +#define TXFCR_FIFO_EN_MASK 0x00000040 + +#define IER_OFFSET 0x00000044 +#define IER_READ_COMPLETE_INT_MASK 0x00000010 +#define IER_I2C_INT_EN_MASK 0x00000008 +#define IER_FIFO_INT_EN_MASK 0x00000002 +#define IER_NOACK_EN_MASK 0x00000001 + +#define ISR_OFFSET 0x00000048 +#define ISR_RESERVED_MASK 0xffffff60 +#define ISR_CMDBUSY_MASK 0x00000080 +#define ISR_READ_COMPLETE_MASK 0x00000010 +#define ISR_SES_DONE_MASK 0x00000008 +#define ISR_ERR_MASK 0x00000004 +#define ISR_TXFIFOEMPTY_MASK 0x00000002 +#define ISR_NOACK_MASK 0x00000001 + +#define CLKEN_OFFSET 0x0000004C +#define CLKEN_AUTOSENSE_OFF_MASK 0x00000080 +#define CLKEN_M_SHIFT 4 +#define CLKEN_N_SHIFT 1 +#define CLKEN_CLKEN_MASK 0x00000001 + +#define FIFO_STATUS_OFFSET 0x00000054 +#define FIFO_STATUS_RXFIFO_EMPTY_MASK 0x00000004 +#define FIFO_STATUS_TXFIFO_EMPTY_MASK 0x00000010 + +#define HSTIM_OFFSET 0x00000058 +#define HSTIM_HS_MODE_MASK 0x00008000 +#define HSTIM_HS_HOLD_SHIFT 10 +#define HSTIM_HS_HIGH_PHASE_SHIFT 5 +#define HSTIM_HS_SETUP_SHIFT 0 + +#define PADCTL_OFFSET 0x0000005c +#define PADCTL_PAD_OUT_EN_MASK 0x00000004 + +#define RXFCR_OFFSET 0x00000068 +#define RXFCR_NACK_EN_SHIFT 7 +#define RXFCR_READ_COUNT_SHIFT 0 +#define RXFIFORDOUT_OFFSET 0x0000006c + +/* Locally used constants */ +#define MAX_RX_FIFO_SIZE 64U /* bytes */ +#define MAX_TX_FIFO_SIZE 64U /* bytes */ + +#define STD_EXT_CLK_FREQ 13000000UL +#define HS_EXT_CLK_FREQ 104000000UL + +#define MASTERCODE 0x08 /* Mastercodes are 0000_1xxxb */ + +#define I2C_TIMEOUT 100 /* msecs */ + +/* Operations that can be commanded to the controller */ +enum bcm_kona_cmd_t { + BCM_CMD_NOACTION = 0, + BCM_CMD_START, + BCM_CMD_RESTART, + BCM_CMD_STOP, +}; + +enum bus_speed_index { + BCM_SPD_100K = 0, + BCM_SPD_400K, + BCM_SPD_1MHZ, +}; + +enum hs_bus_speed_index { + BCM_SPD_3P4MHZ = 0, +}; + +/* Internal divider settings for standard mode, fast mode and fast mode plus */ +struct bus_speed_cfg { + uint8_t time_m; /* Number of cycles for setup time */ + uint8_t time_n; /* Number of cycles for hold time */ + uint8_t prescale; /* Prescale divider */ + uint8_t time_p; /* Timing coefficient */ + uint8_t no_div; /* Disable clock divider */ + uint8_t time_div; /* Post-prescale divider */ +}; + +/* Internal divider settings for high-speed mode */ +struct hs_bus_speed_cfg { + uint8_t hs_hold; /* Number of clock cycles SCL stays low until + the end of bit period */ + uint8_t hs_high_phase; /* Number of clock cycles SCL stays high + before it falls */ + uint8_t hs_setup; /* Number of clock cycles SCL stays low + before it rises */ + uint8_t prescale; /* Prescale divider */ + uint8_t time_p; /* Timing coefficient */ + uint8_t no_div; /* Disable clock divider */ + uint8_t time_div; /* Post-prescale divider */ +}; + +static const struct bus_speed_cfg std_cfg_table[] = { + [BCM_SPD_100K] = {0x01, 0x01, 0x03, 0x06, 0x00, 0x02}, + [BCM_SPD_400K] = {0x05, 0x01, 0x03, 0x05, 0x01, 0x02}, + [BCM_SPD_1MHZ] = {0x01, 0x01, 0x03, 0x01, 0x01, 0x03}, +}; + +static const struct hs_bus_speed_cfg hs_cfg_table[] = { + [BCM_SPD_3P4MHZ] = {0x01, 0x08, 0x14, 0x00, 0x06, 0x01, 0x00}, +}; + +struct bcm_kona_i2c_dev { + struct device *device; + + void __iomem *base; + int irq; + struct clk *external_clk; + + struct i2c_adapter adapter; + + struct completion done; + + const struct bus_speed_cfg *std_cfg; + const struct hs_bus_speed_cfg *hs_cfg; +}; + +static void bcm_kona_i2c_send_cmd_to_ctrl(struct bcm_kona_i2c_dev *dev, + enum bcm_kona_cmd_t cmd) +{ + dev_dbg(dev->device, "%s, %d\n", __func__, cmd); + + switch (cmd) { + case BCM_CMD_NOACTION: + writel((CS_CMD_CMD_NO_ACTION << CS_CMD_SHIFT) | + (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT), + dev->base + CS_OFFSET); + break; + + case BCM_CMD_START: + writel((CS_ACK_CMD_GEN_START << CS_ACK_SHIFT) | + (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) | + (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT), + dev->base + CS_OFFSET); + break; + + case BCM_CMD_RESTART: + writel((CS_ACK_CMD_GEN_RESTART << CS_ACK_SHIFT) | + (CS_CMD_CMD_START_RESTART << CS_CMD_SHIFT) | + (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT), + dev->base + CS_OFFSET); + break; + + case BCM_CMD_STOP: + writel((CS_CMD_CMD_STOP << CS_CMD_SHIFT) | + (CS_EN_CMD_ENABLE_BSC << CS_EN_SHIFT), + dev->base + CS_OFFSET); + break; + + default: + dev_err(dev->device, "Unknown command %d\n", cmd); + } +} + +static void bcm_kona_i2c_enable_clock(struct bcm_kona_i2c_dev *dev) +{ + writel(readl(dev->base + CLKEN_OFFSET) | CLKEN_CLKEN_MASK, + dev->base + CLKEN_OFFSET); +} + +static void bcm_kona_i2c_disable_clock(struct bcm_kona_i2c_dev *dev) +{ + writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_CLKEN_MASK, + dev->base + CLKEN_OFFSET); +} + +static irqreturn_t bcm_kona_i2c_isr(int irq, void *devid) +{ + struct bcm_kona_i2c_dev *dev = devid; + uint32_t status = readl(dev->base + ISR_OFFSET); + + if ((status & ~ISR_RESERVED_MASK) == 0) + return IRQ_NONE; + + /* Must flush the TX FIFO when NAK detected */ + if (status & ISR_NOACK_MASK) + writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK, + dev->base + TXFCR_OFFSET); + + writel(status & ~ISR_RESERVED_MASK, dev->base + ISR_OFFSET); + complete(&dev->done); + + return IRQ_HANDLED; +} + +/* Wait for ISR_CMDBUSY_MASK to go low before writing to CS, DAT, or RCD */ +static int bcm_kona_i2c_wait_if_busy(struct bcm_kona_i2c_dev *dev) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT); + + while (readl(dev->base + ISR_OFFSET) & ISR_CMDBUSY_MASK) + if (time_after(jiffies, timeout)) { + dev_err(dev->device, "CMDBUSY timeout\n"); + return -ETIMEDOUT; + } + + return 0; +} + +/* Send command to I2C bus */ +static int bcm_kona_send_i2c_cmd(struct bcm_kona_i2c_dev *dev, + enum bcm_kona_cmd_t cmd) +{ + int rc; + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT); + + /* Make sure the hardware is ready */ + rc = bcm_kona_i2c_wait_if_busy(dev); + if (rc < 0) + return rc; + + /* Unmask the session done interrupt */ + writel(IER_I2C_INT_EN_MASK, dev->base + IER_OFFSET); + + /* Mark as incomplete before sending the command */ + reinit_completion(&dev->done); + + /* Send the command */ + bcm_kona_i2c_send_cmd_to_ctrl(dev, cmd); + + /* Wait for transaction to finish or timeout */ + time_left = wait_for_completion_timeout(&dev->done, time_left); + + /* Mask all interrupts */ + writel(0, dev->base + IER_OFFSET); + + if (!time_left) { + dev_err(dev->device, "controller timed out\n"); + rc = -ETIMEDOUT; + } + + /* Clear command */ + bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION); + + return rc; +} + +/* Read a single RX FIFO worth of data from the i2c bus */ +static int bcm_kona_i2c_read_fifo_single(struct bcm_kona_i2c_dev *dev, + uint8_t *buf, unsigned int len, + unsigned int last_byte_nak) +{ + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT); + + /* Mark as incomplete before starting the RX FIFO */ + reinit_completion(&dev->done); + + /* Unmask the read complete interrupt */ + writel(IER_READ_COMPLETE_INT_MASK, dev->base + IER_OFFSET); + + /* Start the RX FIFO */ + writel((last_byte_nak << RXFCR_NACK_EN_SHIFT) | + (len << RXFCR_READ_COUNT_SHIFT), + dev->base + RXFCR_OFFSET); + + /* Wait for FIFO read to complete */ + time_left = wait_for_completion_timeout(&dev->done, time_left); + + /* Mask all interrupts */ + writel(0, dev->base + IER_OFFSET); + + if (!time_left) { + dev_err(dev->device, "RX FIFO time out\n"); + return -EREMOTEIO; + } + + /* Read data from FIFO */ + for (; len > 0; len--, buf++) + *buf = readl(dev->base + RXFIFORDOUT_OFFSET); + + return 0; +} + +/* Read any amount of data using the RX FIFO from the i2c bus */ +static int bcm_kona_i2c_read_fifo(struct bcm_kona_i2c_dev *dev, + struct i2c_msg *msg) +{ + unsigned int bytes_to_read = MAX_RX_FIFO_SIZE; + unsigned int last_byte_nak = 0; + unsigned int bytes_read = 0; + int rc; + + uint8_t *tmp_buf = msg->buf; + + while (bytes_read < msg->len) { + if (msg->len - bytes_read <= MAX_RX_FIFO_SIZE) { + last_byte_nak = 1; /* NAK last byte of transfer */ + bytes_to_read = msg->len - bytes_read; + } + + rc = bcm_kona_i2c_read_fifo_single(dev, tmp_buf, bytes_to_read, + last_byte_nak); + if (rc < 0) + return -EREMOTEIO; + + bytes_read += bytes_to_read; + tmp_buf += bytes_to_read; + } + + return 0; +} + +/* Write a single byte of data to the i2c bus */ +static int bcm_kona_i2c_write_byte(struct bcm_kona_i2c_dev *dev, uint8_t data, + unsigned int nak_expected) +{ + int rc; + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT); + unsigned int nak_received; + + /* Make sure the hardware is ready */ + rc = bcm_kona_i2c_wait_if_busy(dev); + if (rc < 0) + return rc; + + /* Clear pending session done interrupt */ + writel(ISR_SES_DONE_MASK, dev->base + ISR_OFFSET); + + /* Unmask the session done interrupt */ + writel(IER_I2C_INT_EN_MASK, dev->base + IER_OFFSET); + + /* Mark as incomplete before sending the data */ + reinit_completion(&dev->done); + + /* Send one byte of data */ + writel(data, dev->base + DAT_OFFSET); + + /* Wait for byte to be written */ + time_left = wait_for_completion_timeout(&dev->done, time_left); + + /* Mask all interrupts */ + writel(0, dev->base + IER_OFFSET); + + if (!time_left) { + dev_dbg(dev->device, "controller timed out\n"); + return -ETIMEDOUT; + } + + nak_received = readl(dev->base + CS_OFFSET) & CS_ACK_MASK ? 1 : 0; + + if (nak_received ^ nak_expected) { + dev_dbg(dev->device, "unexpected NAK/ACK\n"); + return -EREMOTEIO; + } + + return 0; +} + +/* Write a single TX FIFO worth of data to the i2c bus */ +static int bcm_kona_i2c_write_fifo_single(struct bcm_kona_i2c_dev *dev, + uint8_t *buf, unsigned int len) +{ + int k; + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT); + unsigned int fifo_status; + + /* Mark as incomplete before sending data to the TX FIFO */ + reinit_completion(&dev->done); + + /* Unmask the fifo empty and nak interrupt */ + writel(IER_FIFO_INT_EN_MASK | IER_NOACK_EN_MASK, + dev->base + IER_OFFSET); + + /* Disable IRQ to load a FIFO worth of data without interruption */ + disable_irq(dev->irq); + + /* Write data into FIFO */ + for (k = 0; k < len; k++) + writel(buf[k], (dev->base + DAT_OFFSET)); + + /* Enable IRQ now that data has been loaded */ + enable_irq(dev->irq); + + /* Wait for FIFO to empty */ + do { + time_left = wait_for_completion_timeout(&dev->done, time_left); + fifo_status = readl(dev->base + FIFO_STATUS_OFFSET); + } while (time_left && !(fifo_status & FIFO_STATUS_TXFIFO_EMPTY_MASK)); + + /* Mask all interrupts */ + writel(0, dev->base + IER_OFFSET); + + /* Check if there was a NAK */ + if (readl(dev->base + CS_OFFSET) & CS_ACK_MASK) { + dev_err(dev->device, "unexpected NAK\n"); + return -EREMOTEIO; + } + + /* Check if a timeout occured */ + if (!time_left) { + dev_err(dev->device, "completion timed out\n"); + return -EREMOTEIO; + } + + return 0; +} + + +/* Write any amount of data using TX FIFO to the i2c bus */ +static int bcm_kona_i2c_write_fifo(struct bcm_kona_i2c_dev *dev, + struct i2c_msg *msg) +{ + unsigned int bytes_to_write = MAX_TX_FIFO_SIZE; + unsigned int bytes_written = 0; + int rc; + + uint8_t *tmp_buf = msg->buf; + + while (bytes_written < msg->len) { + if (msg->len - bytes_written <= MAX_TX_FIFO_SIZE) + bytes_to_write = msg->len - bytes_written; + + rc = bcm_kona_i2c_write_fifo_single(dev, tmp_buf, + bytes_to_write); + if (rc < 0) + return -EREMOTEIO; + + bytes_written += bytes_to_write; + tmp_buf += bytes_to_write; + } + + return 0; +} + +/* Send i2c address */ +static int bcm_kona_i2c_do_addr(struct bcm_kona_i2c_dev *dev, + struct i2c_msg *msg) +{ + unsigned char addr; + + if (msg->flags & I2C_M_TEN) { + /* First byte is 11110XX0 where XX is upper 2 bits */ + addr = 0xF0 | ((msg->addr & 0x300) >> 7); + if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0) + return -EREMOTEIO; + + /* Second byte is the remaining 8 bits */ + addr = msg->addr & 0xFF; + if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0) + return -EREMOTEIO; + + if (msg->flags & I2C_M_RD) { + /* For read, send restart command */ + if (bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART) < 0) + return -EREMOTEIO; + + /* Then re-send the first byte with the read bit set */ + addr = 0xF0 | ((msg->addr & 0x300) >> 7) | 0x01; + if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0) + return -EREMOTEIO; + } + } else { + addr = i2c_8bit_addr_from_msg(msg); + + if (bcm_kona_i2c_write_byte(dev, addr, 0) < 0) + return -EREMOTEIO; + } + + return 0; +} + +static void bcm_kona_i2c_enable_autosense(struct bcm_kona_i2c_dev *dev) +{ + writel(readl(dev->base + CLKEN_OFFSET) & ~CLKEN_AUTOSENSE_OFF_MASK, + dev->base + CLKEN_OFFSET); +} + +static void bcm_kona_i2c_config_timing(struct bcm_kona_i2c_dev *dev) +{ + writel(readl(dev->base + HSTIM_OFFSET) & ~HSTIM_HS_MODE_MASK, + dev->base + HSTIM_OFFSET); + + writel((dev->std_cfg->prescale << TIM_PRESCALE_SHIFT) | + (dev->std_cfg->time_p << TIM_P_SHIFT) | + (dev->std_cfg->no_div << TIM_NO_DIV_SHIFT) | + (dev->std_cfg->time_div << TIM_DIV_SHIFT), + dev->base + TIM_OFFSET); + + writel((dev->std_cfg->time_m << CLKEN_M_SHIFT) | + (dev->std_cfg->time_n << CLKEN_N_SHIFT) | + CLKEN_CLKEN_MASK, + dev->base + CLKEN_OFFSET); +} + +static void bcm_kona_i2c_config_timing_hs(struct bcm_kona_i2c_dev *dev) +{ + writel((dev->hs_cfg->prescale << TIM_PRESCALE_SHIFT) | + (dev->hs_cfg->time_p << TIM_P_SHIFT) | + (dev->hs_cfg->no_div << TIM_NO_DIV_SHIFT) | + (dev->hs_cfg->time_div << TIM_DIV_SHIFT), + dev->base + TIM_OFFSET); + + writel((dev->hs_cfg->hs_hold << HSTIM_HS_HOLD_SHIFT) | + (dev->hs_cfg->hs_high_phase << HSTIM_HS_HIGH_PHASE_SHIFT) | + (dev->hs_cfg->hs_setup << HSTIM_HS_SETUP_SHIFT), + dev->base + HSTIM_OFFSET); + + writel(readl(dev->base + HSTIM_OFFSET) | HSTIM_HS_MODE_MASK, + dev->base + HSTIM_OFFSET); +} + +static int bcm_kona_i2c_switch_to_hs(struct bcm_kona_i2c_dev *dev) +{ + int rc; + + /* Send mastercode at standard speed */ + rc = bcm_kona_i2c_write_byte(dev, MASTERCODE, 1); + if (rc < 0) { + pr_err("High speed handshake failed\n"); + return rc; + } + + /* Configure external clock to higher frequency */ + rc = clk_set_rate(dev->external_clk, HS_EXT_CLK_FREQ); + if (rc) { + dev_err(dev->device, "%s: clk_set_rate returned %d\n", + __func__, rc); + return rc; + } + + /* Reconfigure internal dividers */ + bcm_kona_i2c_config_timing_hs(dev); + + /* Send a restart command */ + rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART); + if (rc < 0) + dev_err(dev->device, "High speed restart command failed\n"); + + return rc; +} + +static int bcm_kona_i2c_switch_to_std(struct bcm_kona_i2c_dev *dev) +{ + int rc; + + /* Reconfigure internal dividers */ + bcm_kona_i2c_config_timing(dev); + + /* Configure external clock to lower frequency */ + rc = clk_set_rate(dev->external_clk, STD_EXT_CLK_FREQ); + if (rc) { + dev_err(dev->device, "%s: clk_set_rate returned %d\n", + __func__, rc); + } + + return rc; +} + +/* Master transfer function */ +static int bcm_kona_i2c_xfer(struct i2c_adapter *adapter, + struct i2c_msg msgs[], int num) +{ + struct bcm_kona_i2c_dev *dev = i2c_get_adapdata(adapter); + struct i2c_msg *pmsg; + int rc = 0; + int i; + + rc = clk_prepare_enable(dev->external_clk); + if (rc) { + dev_err(dev->device, "%s: peri clock enable failed. err %d\n", + __func__, rc); + return rc; + } + + /* Enable pad output */ + writel(0, dev->base + PADCTL_OFFSET); + + /* Enable internal clocks */ + bcm_kona_i2c_enable_clock(dev); + + /* Send start command */ + rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_START); + if (rc < 0) { + dev_err(dev->device, "Start command failed rc = %d\n", rc); + goto xfer_disable_pad; + } + + /* Switch to high speed if applicable */ + if (dev->hs_cfg) { + rc = bcm_kona_i2c_switch_to_hs(dev); + if (rc < 0) + goto xfer_send_stop; + } + + /* Loop through all messages */ + for (i = 0; i < num; i++) { + pmsg = &msgs[i]; + + /* Send restart for subsequent messages */ + if ((i != 0) && ((pmsg->flags & I2C_M_NOSTART) == 0)) { + rc = bcm_kona_send_i2c_cmd(dev, BCM_CMD_RESTART); + if (rc < 0) { + dev_err(dev->device, + "restart cmd failed rc = %d\n", rc); + goto xfer_send_stop; + } + } + + /* Send slave address */ + if (!(pmsg->flags & I2C_M_NOSTART)) { + rc = bcm_kona_i2c_do_addr(dev, pmsg); + if (rc < 0) { + dev_err(dev->device, + "NAK from addr %2.2x msg#%d rc = %d\n", + pmsg->addr, i, rc); + goto xfer_send_stop; + } + } + + /* Perform data transfer */ + if (pmsg->flags & I2C_M_RD) { + rc = bcm_kona_i2c_read_fifo(dev, pmsg); + if (rc < 0) { + dev_err(dev->device, "read failure\n"); + goto xfer_send_stop; + } + } else { + rc = bcm_kona_i2c_write_fifo(dev, pmsg); + if (rc < 0) { + dev_err(dev->device, "write failure"); + goto xfer_send_stop; + } + } + } + + rc = num; + +xfer_send_stop: + /* Send a STOP command */ + bcm_kona_send_i2c_cmd(dev, BCM_CMD_STOP); + + /* Return from high speed if applicable */ + if (dev->hs_cfg) { + int hs_rc = bcm_kona_i2c_switch_to_std(dev); + + if (hs_rc) + rc = hs_rc; + } + +xfer_disable_pad: + /* Disable pad output */ + writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET); + + /* Stop internal clock */ + bcm_kona_i2c_disable_clock(dev); + + clk_disable_unprepare(dev->external_clk); + + return rc; +} + +static uint32_t bcm_kona_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | + I2C_FUNC_NOSTART; +} + +static const struct i2c_algorithm bcm_algo = { + .master_xfer = bcm_kona_i2c_xfer, + .functionality = bcm_kona_i2c_functionality, +}; + +static int bcm_kona_i2c_assign_bus_speed(struct bcm_kona_i2c_dev *dev) +{ + unsigned int bus_speed; + int ret = of_property_read_u32(dev->device->of_node, "clock-frequency", + &bus_speed); + if (ret < 0) { + dev_err(dev->device, "missing clock-frequency property\n"); + return -ENODEV; + } + + switch (bus_speed) { + case I2C_MAX_STANDARD_MODE_FREQ: + dev->std_cfg = &std_cfg_table[BCM_SPD_100K]; + break; + case I2C_MAX_FAST_MODE_FREQ: + dev->std_cfg = &std_cfg_table[BCM_SPD_400K]; + break; + case I2C_MAX_FAST_MODE_PLUS_FREQ: + dev->std_cfg = &std_cfg_table[BCM_SPD_1MHZ]; + break; + case I2C_MAX_HIGH_SPEED_MODE_FREQ: + /* Send mastercode at 100k */ + dev->std_cfg = &std_cfg_table[BCM_SPD_100K]; + dev->hs_cfg = &hs_cfg_table[BCM_SPD_3P4MHZ]; + break; + default: + pr_err("%d hz bus speed not supported\n", bus_speed); + pr_err("Valid speeds are 100khz, 400khz, 1mhz, and 3.4mhz\n"); + return -EINVAL; + } + + return 0; +} + +static int bcm_kona_i2c_probe(struct platform_device *pdev) +{ + int rc = 0; + struct bcm_kona_i2c_dev *dev; + struct i2c_adapter *adap; + + /* Allocate memory for private data structure */ + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); + if (!dev) + return -ENOMEM; + + platform_set_drvdata(pdev, dev); + dev->device = &pdev->dev; + init_completion(&dev->done); + + /* Map hardware registers */ + dev->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(dev->base)) + return PTR_ERR(dev->base); + + /* Get and enable external clock */ + dev->external_clk = devm_clk_get(dev->device, NULL); + if (IS_ERR(dev->external_clk)) { + dev_err(dev->device, "couldn't get clock\n"); + return -ENODEV; + } + + rc = clk_set_rate(dev->external_clk, STD_EXT_CLK_FREQ); + if (rc) { + dev_err(dev->device, "%s: clk_set_rate returned %d\n", + __func__, rc); + return rc; + } + + rc = clk_prepare_enable(dev->external_clk); + if (rc) { + dev_err(dev->device, "couldn't enable clock\n"); + return rc; + } + + /* Parse bus speed */ + rc = bcm_kona_i2c_assign_bus_speed(dev); + if (rc) + goto probe_disable_clk; + + /* Enable internal clocks */ + bcm_kona_i2c_enable_clock(dev); + + /* Configure internal dividers */ + bcm_kona_i2c_config_timing(dev); + + /* Disable timeout */ + writel(0, dev->base + TOUT_OFFSET); + + /* Enable autosense */ + bcm_kona_i2c_enable_autosense(dev); + + /* Enable TX FIFO */ + writel(TXFCR_FIFO_FLUSH_MASK | TXFCR_FIFO_EN_MASK, + dev->base + TXFCR_OFFSET); + + /* Mask all interrupts */ + writel(0, dev->base + IER_OFFSET); + + /* Clear all pending interrupts */ + writel(ISR_CMDBUSY_MASK | + ISR_READ_COMPLETE_MASK | + ISR_SES_DONE_MASK | + ISR_ERR_MASK | + ISR_TXFIFOEMPTY_MASK | + ISR_NOACK_MASK, + dev->base + ISR_OFFSET); + + /* Get the interrupt number */ + dev->irq = platform_get_irq(pdev, 0); + if (dev->irq < 0) { + rc = dev->irq; + goto probe_disable_clk; + } + + /* register the ISR handler */ + rc = devm_request_irq(&pdev->dev, dev->irq, bcm_kona_i2c_isr, + IRQF_SHARED, pdev->name, dev); + if (rc) { + dev_err(dev->device, "failed to request irq %i\n", dev->irq); + goto probe_disable_clk; + } + + /* Enable the controller but leave it idle */ + bcm_kona_i2c_send_cmd_to_ctrl(dev, BCM_CMD_NOACTION); + + /* Disable pad output */ + writel(PADCTL_PAD_OUT_EN_MASK, dev->base + PADCTL_OFFSET); + + /* Disable internal clock */ + bcm_kona_i2c_disable_clock(dev); + + /* Disable external clock */ + clk_disable_unprepare(dev->external_clk); + + /* Add the i2c adapter */ + adap = &dev->adapter; + i2c_set_adapdata(adap, dev); + adap->owner = THIS_MODULE; + strscpy(adap->name, "Broadcom I2C adapter", sizeof(adap->name)); + adap->algo = &bcm_algo; + adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; + + rc = i2c_add_adapter(adap); + if (rc) + return rc; + + dev_info(dev->device, "device registered successfully\n"); + + return 0; + +probe_disable_clk: + bcm_kona_i2c_disable_clock(dev); + clk_disable_unprepare(dev->external_clk); + + return rc; +} + +static void bcm_kona_i2c_remove(struct platform_device *pdev) +{ + struct bcm_kona_i2c_dev *dev = platform_get_drvdata(pdev); + + i2c_del_adapter(&dev->adapter); +} + +static const struct of_device_id bcm_kona_i2c_of_match[] = { + {.compatible = "brcm,kona-i2c",}, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm_kona_i2c_of_match); + +static struct platform_driver bcm_kona_i2c_driver = { + .driver = { + .name = "bcm-kona-i2c", + .of_match_table = bcm_kona_i2c_of_match, + }, + .probe = bcm_kona_i2c_probe, + .remove_new = bcm_kona_i2c_remove, +}; +module_platform_driver(bcm_kona_i2c_driver); + +MODULE_AUTHOR("Tim Kryger <tkryger@broadcom.com>"); +MODULE_DESCRIPTION("Broadcom Kona I2C Driver"); +MODULE_LICENSE("GPL v2"); |