diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-img-scb.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-img-scb.c | 1522 |
1 files changed, 1522 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c new file mode 100644 index 000000000..f038858b6 --- /dev/null +++ b/drivers/i2c/busses/i2c-img-scb.c @@ -0,0 +1,1522 @@ +/* + * I2C adapter for the IMG Serial Control Bus (SCB) IP block. + * + * Copyright (C) 2009, 2010, 2012, 2014 Imagination Technologies Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * There are three ways that this I2C controller can be driven: + * + * - Raw control of the SDA and SCK signals. + * + * This corresponds to MODE_RAW, which takes control of the signals + * directly for a certain number of clock cycles (the INT_TIMING + * interrupt can be used for timing). + * + * - Atomic commands. A low level I2C symbol (such as generate + * start/stop/ack/nack bit, generate byte, receive byte, and receive + * ACK) is given to the hardware, with detection of completion by bits + * in the LINESTAT register. + * + * This mode of operation is used by MODE_ATOMIC, which uses an I2C + * state machine in the interrupt handler to compose/react to I2C + * transactions using atomic mode commands, and also by MODE_SEQUENCE, + * which emits a simple fixed sequence of atomic mode commands. + * + * Due to software control, the use of atomic commands usually results + * in suboptimal use of the bus, with gaps between the I2C symbols while + * the driver decides what to do next. + * + * - Automatic mode. A bus address, and whether to read/write is + * specified, and the hardware takes care of the I2C state machine, + * using a FIFO to send/receive bytes of data to an I2C slave. The + * driver just has to keep the FIFO drained or filled in response to the + * appropriate FIFO interrupts. + * + * This corresponds to MODE_AUTOMATIC, which manages the FIFOs and deals + * with control of repeated start bits between I2C messages. + * + * Use of automatic mode and the FIFO can make much more efficient use + * of the bus compared to individual atomic commands, with potentially + * no wasted time between I2C symbols or I2C messages. + * + * In most cases MODE_AUTOMATIC is used, however if any of the messages in + * a transaction are zero byte writes (e.g. used by i2cdetect for probing + * the bus), MODE_ATOMIC must be used since automatic mode is normally + * started by the writing of data into the FIFO. + * + * The other modes are used in specific circumstances where MODE_ATOMIC and + * MODE_AUTOMATIC aren't appropriate. MODE_RAW is used to implement a bus + * recovery routine. MODE_SEQUENCE is used to reset the bus and make sure + * it is in a sane state. + * + * Notice that the driver implements a timer-based timeout mechanism. + * The reason for this mechanism is to reduce the number of interrupts + * received in automatic mode. + * + * The driver would get a slave event and transaction done interrupts for + * each atomic mode command that gets completed. However, these events are + * not needed in automatic mode, becase those atomic mode commands are + * managed automatically by the hardware. + * + * In practice, normal I2C transactions will be complete well before you + * get the timer interrupt, as the timer is re-scheduled during FIFO + * maintenance and disabled after the transaction is complete. + * + * In this way normal automatic mode operation isn't impacted by + * unnecessary interrupts, but the exceptional abort condition can still be + * detected (with a slight delay). + */ + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/slab.h> +#include <linux/timer.h> + +/* Register offsets */ + +#define SCB_STATUS_REG 0x00 +#define SCB_OVERRIDE_REG 0x04 +#define SCB_READ_ADDR_REG 0x08 +#define SCB_READ_COUNT_REG 0x0c +#define SCB_WRITE_ADDR_REG 0x10 +#define SCB_READ_DATA_REG 0x14 +#define SCB_WRITE_DATA_REG 0x18 +#define SCB_FIFO_STATUS_REG 0x1c +#define SCB_CONTROL_SOFT_RESET 0x1f +#define SCB_CLK_SET_REG 0x3c +#define SCB_INT_STATUS_REG 0x40 +#define SCB_INT_CLEAR_REG 0x44 +#define SCB_INT_MASK_REG 0x48 +#define SCB_CONTROL_REG 0x4c +#define SCB_TIME_TPL_REG 0x50 +#define SCB_TIME_TPH_REG 0x54 +#define SCB_TIME_TP2S_REG 0x58 +#define SCB_TIME_TBI_REG 0x60 +#define SCB_TIME_TSL_REG 0x64 +#define SCB_TIME_TDL_REG 0x68 +#define SCB_TIME_TSDL_REG 0x6c +#define SCB_TIME_TSDH_REG 0x70 +#define SCB_READ_XADDR_REG 0x74 +#define SCB_WRITE_XADDR_REG 0x78 +#define SCB_WRITE_COUNT_REG 0x7c +#define SCB_CORE_REV_REG 0x80 +#define SCB_TIME_TCKH_REG 0x84 +#define SCB_TIME_TCKL_REG 0x88 +#define SCB_FIFO_FLUSH_REG 0x8c +#define SCB_READ_FIFO_REG 0x94 +#define SCB_CLEAR_REG 0x98 + +/* SCB_CONTROL_REG bits */ + +#define SCB_CONTROL_CLK_ENABLE 0x1e0 +#define SCB_CONTROL_TRANSACTION_HALT 0x200 + +#define FIFO_READ_FULL BIT(0) +#define FIFO_READ_EMPTY BIT(1) +#define FIFO_WRITE_FULL BIT(2) +#define FIFO_WRITE_EMPTY BIT(3) + +/* SCB_CLK_SET_REG bits */ +#define SCB_FILT_DISABLE BIT(31) +#define SCB_FILT_BYPASS BIT(30) +#define SCB_FILT_INC_MASK 0x7f +#define SCB_FILT_INC_SHIFT 16 +#define SCB_INC_MASK 0x7f +#define SCB_INC_SHIFT 8 + +/* SCB_INT_*_REG bits */ + +#define INT_BUS_INACTIVE BIT(0) +#define INT_UNEXPECTED_START BIT(1) +#define INT_SCLK_LOW_TIMEOUT BIT(2) +#define INT_SDAT_LOW_TIMEOUT BIT(3) +#define INT_WRITE_ACK_ERR BIT(4) +#define INT_ADDR_ACK_ERR BIT(5) +#define INT_FIFO_FULL BIT(9) +#define INT_FIFO_FILLING BIT(10) +#define INT_FIFO_EMPTY BIT(11) +#define INT_FIFO_EMPTYING BIT(12) +#define INT_TRANSACTION_DONE BIT(15) +#define INT_SLAVE_EVENT BIT(16) +#define INT_MASTER_HALTED BIT(17) +#define INT_TIMING BIT(18) +#define INT_STOP_DETECTED BIT(19) + +#define INT_FIFO_FULL_FILLING (INT_FIFO_FULL | INT_FIFO_FILLING) + +/* Level interrupts need clearing after handling instead of before */ +#define INT_LEVEL 0x01e00 + +/* Don't allow any interrupts while the clock may be off */ +#define INT_ENABLE_MASK_INACTIVE 0x00000 + +/* Interrupt masks for the different driver modes */ + +#define INT_ENABLE_MASK_RAW INT_TIMING + +#define INT_ENABLE_MASK_ATOMIC (INT_TRANSACTION_DONE | \ + INT_SLAVE_EVENT | \ + INT_ADDR_ACK_ERR | \ + INT_WRITE_ACK_ERR) + +#define INT_ENABLE_MASK_AUTOMATIC (INT_SCLK_LOW_TIMEOUT | \ + INT_ADDR_ACK_ERR | \ + INT_WRITE_ACK_ERR | \ + INT_FIFO_FULL | \ + INT_FIFO_FILLING | \ + INT_FIFO_EMPTY | \ + INT_MASTER_HALTED | \ + INT_STOP_DETECTED) + +#define INT_ENABLE_MASK_WAITSTOP (INT_SLAVE_EVENT | \ + INT_ADDR_ACK_ERR | \ + INT_WRITE_ACK_ERR) + +/* SCB_STATUS_REG fields */ + +#define LINESTAT_SCLK_LINE_STATUS BIT(0) +#define LINESTAT_SCLK_EN BIT(1) +#define LINESTAT_SDAT_LINE_STATUS BIT(2) +#define LINESTAT_SDAT_EN BIT(3) +#define LINESTAT_DET_START_STATUS BIT(4) +#define LINESTAT_DET_STOP_STATUS BIT(5) +#define LINESTAT_DET_ACK_STATUS BIT(6) +#define LINESTAT_DET_NACK_STATUS BIT(7) +#define LINESTAT_BUS_IDLE BIT(8) +#define LINESTAT_T_DONE_STATUS BIT(9) +#define LINESTAT_SCLK_OUT_STATUS BIT(10) +#define LINESTAT_SDAT_OUT_STATUS BIT(11) +#define LINESTAT_GEN_LINE_MASK_STATUS BIT(12) +#define LINESTAT_START_BIT_DET BIT(13) +#define LINESTAT_STOP_BIT_DET BIT(14) +#define LINESTAT_ACK_DET BIT(15) +#define LINESTAT_NACK_DET BIT(16) +#define LINESTAT_INPUT_HELD_V BIT(17) +#define LINESTAT_ABORT_DET BIT(18) +#define LINESTAT_ACK_OR_NACK_DET (LINESTAT_ACK_DET | LINESTAT_NACK_DET) +#define LINESTAT_INPUT_DATA 0xff000000 +#define LINESTAT_INPUT_DATA_SHIFT 24 + +#define LINESTAT_CLEAR_SHIFT 13 +#define LINESTAT_LATCHED (0x3f << LINESTAT_CLEAR_SHIFT) + +/* SCB_OVERRIDE_REG fields */ + +#define OVERRIDE_SCLK_OVR BIT(0) +#define OVERRIDE_SCLKEN_OVR BIT(1) +#define OVERRIDE_SDAT_OVR BIT(2) +#define OVERRIDE_SDATEN_OVR BIT(3) +#define OVERRIDE_MASTER BIT(9) +#define OVERRIDE_LINE_OVR_EN BIT(10) +#define OVERRIDE_DIRECT BIT(11) +#define OVERRIDE_CMD_SHIFT 4 +#define OVERRIDE_CMD_MASK 0x1f +#define OVERRIDE_DATA_SHIFT 24 + +#define OVERRIDE_SCLK_DOWN (OVERRIDE_LINE_OVR_EN | \ + OVERRIDE_SCLKEN_OVR) +#define OVERRIDE_SCLK_UP (OVERRIDE_LINE_OVR_EN | \ + OVERRIDE_SCLKEN_OVR | \ + OVERRIDE_SCLK_OVR) +#define OVERRIDE_SDAT_DOWN (OVERRIDE_LINE_OVR_EN | \ + OVERRIDE_SDATEN_OVR) +#define OVERRIDE_SDAT_UP (OVERRIDE_LINE_OVR_EN | \ + OVERRIDE_SDATEN_OVR | \ + OVERRIDE_SDAT_OVR) + +/* OVERRIDE_CMD values */ + +#define CMD_PAUSE 0x00 +#define CMD_GEN_DATA 0x01 +#define CMD_GEN_START 0x02 +#define CMD_GEN_STOP 0x03 +#define CMD_GEN_ACK 0x04 +#define CMD_GEN_NACK 0x05 +#define CMD_RET_DATA 0x08 +#define CMD_RET_ACK 0x09 + +/* Fixed timing values */ + +#define TIMEOUT_TBI 0x0 +#define TIMEOUT_TSL 0xffff +#define TIMEOUT_TDL 0x0 + +/* Transaction timeout */ + +#define IMG_I2C_TIMEOUT (msecs_to_jiffies(1000)) + +/* + * Worst incs are 1 (innacurate) and 16*256 (irregular). + * So a sensible inc is the logarithmic mean: 64 (2^6), which is + * in the middle of the valid range (0-127). + */ +#define SCB_OPT_INC 64 + +/* Setup the clock enable filtering for 25 ns */ +#define SCB_FILT_GLITCH 25 + +/* + * Bits to return from interrupt handler functions for different modes. + * This delays completion until we've finished with the registers, so that the + * function waiting for completion can safely disable the clock to save power. + */ +#define ISR_COMPLETE_M BIT(31) +#define ISR_FATAL_M BIT(30) +#define ISR_WAITSTOP BIT(29) +#define ISR_STATUS_M 0x0000ffff /* contains +ve errno */ +#define ISR_COMPLETE(err) (ISR_COMPLETE_M | (ISR_STATUS_M & (err))) +#define ISR_FATAL(err) (ISR_COMPLETE(err) | ISR_FATAL_M) + +#define IMG_I2C_PM_TIMEOUT 1000 /* ms */ + +enum img_i2c_mode { + MODE_INACTIVE, + MODE_RAW, + MODE_ATOMIC, + MODE_AUTOMATIC, + MODE_SEQUENCE, + MODE_FATAL, + MODE_WAITSTOP, + MODE_SUSPEND, +}; + +/* Timing parameters for i2c modes (in ns) */ +struct img_i2c_timings { + const char *name; + unsigned int max_bitrate; + unsigned int tckh, tckl, tsdh, tsdl; + unsigned int tp2s, tpl, tph; +}; + +/* The timings array must be ordered from slower to faster */ +static struct img_i2c_timings timings[] = { + /* Standard mode */ + { + .name = "standard", + .max_bitrate = 100000, + .tckh = 4000, + .tckl = 4700, + .tsdh = 4700, + .tsdl = 8700, + .tp2s = 4700, + .tpl = 4700, + .tph = 4000, + }, + /* Fast mode */ + { + .name = "fast", + .max_bitrate = 400000, + .tckh = 600, + .tckl = 1300, + .tsdh = 600, + .tsdl = 1200, + .tp2s = 1300, + .tpl = 600, + .tph = 600, + }, +}; + +/* Reset dance */ +static u8 img_i2c_reset_seq[] = { CMD_GEN_START, + CMD_GEN_DATA, 0xff, + CMD_RET_ACK, + CMD_GEN_START, + CMD_GEN_STOP, + 0 }; +/* Just issue a stop (after an abort condition) */ +static u8 img_i2c_stop_seq[] = { CMD_GEN_STOP, + 0 }; + +/* We're interested in different interrupts depending on the mode */ +static unsigned int img_i2c_int_enable_by_mode[] = { + [MODE_INACTIVE] = INT_ENABLE_MASK_INACTIVE, + [MODE_RAW] = INT_ENABLE_MASK_RAW, + [MODE_ATOMIC] = INT_ENABLE_MASK_ATOMIC, + [MODE_AUTOMATIC] = INT_ENABLE_MASK_AUTOMATIC, + [MODE_SEQUENCE] = INT_ENABLE_MASK_ATOMIC, + [MODE_FATAL] = 0, + [MODE_WAITSTOP] = INT_ENABLE_MASK_WAITSTOP, + [MODE_SUSPEND] = 0, +}; + +/* Atomic command names */ +static const char * const img_i2c_atomic_cmd_names[] = { + [CMD_PAUSE] = "PAUSE", + [CMD_GEN_DATA] = "GEN_DATA", + [CMD_GEN_START] = "GEN_START", + [CMD_GEN_STOP] = "GEN_STOP", + [CMD_GEN_ACK] = "GEN_ACK", + [CMD_GEN_NACK] = "GEN_NACK", + [CMD_RET_DATA] = "RET_DATA", + [CMD_RET_ACK] = "RET_ACK", +}; + +struct img_i2c { + struct i2c_adapter adap; + + void __iomem *base; + + /* + * The scb core clock is used to get the input frequency, and to disable + * it after every set of transactions to save some power. + */ + struct clk *scb_clk, *sys_clk; + unsigned int bitrate; + bool need_wr_rd_fence; + + /* state */ + struct completion msg_complete; + spinlock_t lock; /* lock before doing anything with the state */ + struct i2c_msg msg; + + /* After the last transaction, wait for a stop bit */ + bool last_msg; + int msg_status; + + enum img_i2c_mode mode; + u32 int_enable; /* depends on mode */ + u32 line_status; /* line status over command */ + + /* + * To avoid slave event interrupts in automatic mode, use a timer to + * poll the abort condition if we don't get an interrupt for too long. + */ + struct timer_list check_timer; + bool t_halt; + + /* atomic mode state */ + bool at_t_done; + bool at_slave_event; + int at_cur_cmd; + u8 at_cur_data; + + /* Sequence: either reset or stop. See img_i2c_sequence. */ + u8 *seq; + + /* raw mode */ + unsigned int raw_timeout; +}; + +static int img_i2c_runtime_suspend(struct device *dev); +static int img_i2c_runtime_resume(struct device *dev); + +static void img_i2c_writel(struct img_i2c *i2c, u32 offset, u32 value) +{ + writel(value, i2c->base + offset); +} + +static u32 img_i2c_readl(struct img_i2c *i2c, u32 offset) +{ + return readl(i2c->base + offset); +} + +/* + * The code to read from the master read fifo, and write to the master + * write fifo, checks a bit in an SCB register before every byte to + * ensure that the fifo is not full (write fifo) or empty (read fifo). + * Due to clock domain crossing inside the SCB block the updated value + * of this bit is only visible after 2 cycles. + * + * The scb_wr_rd_fence() function does 2 dummy writes (to the read-only + * revision register), and it's called after reading from or writing to the + * fifos to ensure that subsequent reads of the fifo status bits do not read + * stale values. + */ +static void img_i2c_wr_rd_fence(struct img_i2c *i2c) +{ + if (i2c->need_wr_rd_fence) { + img_i2c_writel(i2c, SCB_CORE_REV_REG, 0); + img_i2c_writel(i2c, SCB_CORE_REV_REG, 0); + } +} + +static void img_i2c_switch_mode(struct img_i2c *i2c, enum img_i2c_mode mode) +{ + i2c->mode = mode; + i2c->int_enable = img_i2c_int_enable_by_mode[mode]; + i2c->line_status = 0; +} + +static void img_i2c_raw_op(struct img_i2c *i2c) +{ + i2c->raw_timeout = 0; + img_i2c_writel(i2c, SCB_OVERRIDE_REG, + OVERRIDE_SCLKEN_OVR | + OVERRIDE_SDATEN_OVR | + OVERRIDE_MASTER | + OVERRIDE_LINE_OVR_EN | + OVERRIDE_DIRECT | + ((i2c->at_cur_cmd & OVERRIDE_CMD_MASK) << OVERRIDE_CMD_SHIFT) | + (i2c->at_cur_data << OVERRIDE_DATA_SHIFT)); +} + +static const char *img_i2c_atomic_op_name(unsigned int cmd) +{ + if (unlikely(cmd >= ARRAY_SIZE(img_i2c_atomic_cmd_names))) + return "UNKNOWN"; + return img_i2c_atomic_cmd_names[cmd]; +} + +/* Send a single atomic mode command to the hardware */ +static void img_i2c_atomic_op(struct img_i2c *i2c, int cmd, u8 data) +{ + i2c->at_cur_cmd = cmd; + i2c->at_cur_data = data; + + /* work around lack of data setup time when generating data */ + if (cmd == CMD_GEN_DATA && i2c->mode == MODE_ATOMIC) { + u32 line_status = img_i2c_readl(i2c, SCB_STATUS_REG); + + if (line_status & LINESTAT_SDAT_LINE_STATUS && !(data & 0x80)) { + /* hold the data line down for a moment */ + img_i2c_switch_mode(i2c, MODE_RAW); + img_i2c_raw_op(i2c); + return; + } + } + + dev_dbg(i2c->adap.dev.parent, + "atomic cmd=%s (%d) data=%#x\n", + img_i2c_atomic_op_name(cmd), cmd, data); + i2c->at_t_done = (cmd == CMD_RET_DATA || cmd == CMD_RET_ACK); + i2c->at_slave_event = false; + i2c->line_status = 0; + + img_i2c_writel(i2c, SCB_OVERRIDE_REG, + ((cmd & OVERRIDE_CMD_MASK) << OVERRIDE_CMD_SHIFT) | + OVERRIDE_MASTER | + OVERRIDE_DIRECT | + (data << OVERRIDE_DATA_SHIFT)); +} + +/* Start a transaction in atomic mode */ +static void img_i2c_atomic_start(struct img_i2c *i2c) +{ + img_i2c_switch_mode(i2c, MODE_ATOMIC); + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); + img_i2c_atomic_op(i2c, CMD_GEN_START, 0x00); +} + +static void img_i2c_soft_reset(struct img_i2c *i2c) +{ + i2c->t_halt = false; + img_i2c_writel(i2c, SCB_CONTROL_REG, 0); + img_i2c_writel(i2c, SCB_CONTROL_REG, + SCB_CONTROL_CLK_ENABLE | SCB_CONTROL_SOFT_RESET); +} + +/* + * Enable or release transaction halt for control of repeated starts. + * In version 3.3 of the IP when transaction halt is set, an interrupt + * will be generated after each byte of a transfer instead of after + * every transfer but before the stop bit. + * Due to this behaviour we have to be careful that every time we + * release the transaction halt we have to re-enable it straight away + * so that we only process a single byte, not doing so will result in + * all remaining bytes been processed and a stop bit being issued, + * which will prevent us having a repeated start. + */ +static void img_i2c_transaction_halt(struct img_i2c *i2c, bool t_halt) +{ + u32 val; + + if (i2c->t_halt == t_halt) + return; + i2c->t_halt = t_halt; + val = img_i2c_readl(i2c, SCB_CONTROL_REG); + if (t_halt) + val |= SCB_CONTROL_TRANSACTION_HALT; + else + val &= ~SCB_CONTROL_TRANSACTION_HALT; + img_i2c_writel(i2c, SCB_CONTROL_REG, val); +} + +/* Drain data from the FIFO into the buffer (automatic mode) */ +static void img_i2c_read_fifo(struct img_i2c *i2c) +{ + while (i2c->msg.len) { + u32 fifo_status; + u8 data; + + img_i2c_wr_rd_fence(i2c); + fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG); + if (fifo_status & FIFO_READ_EMPTY) + break; + + data = img_i2c_readl(i2c, SCB_READ_DATA_REG); + *i2c->msg.buf = data; + + img_i2c_writel(i2c, SCB_READ_FIFO_REG, 0xff); + i2c->msg.len--; + i2c->msg.buf++; + } +} + +/* Fill the FIFO with data from the buffer (automatic mode) */ +static void img_i2c_write_fifo(struct img_i2c *i2c) +{ + while (i2c->msg.len) { + u32 fifo_status; + + img_i2c_wr_rd_fence(i2c); + fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG); + if (fifo_status & FIFO_WRITE_FULL) + break; + + img_i2c_writel(i2c, SCB_WRITE_DATA_REG, *i2c->msg.buf); + i2c->msg.len--; + i2c->msg.buf++; + } + + /* Disable fifo emptying interrupt if nothing more to write */ + if (!i2c->msg.len) + i2c->int_enable &= ~INT_FIFO_EMPTYING; +} + +/* Start a read transaction in automatic mode */ +static void img_i2c_read(struct img_i2c *i2c) +{ + img_i2c_switch_mode(i2c, MODE_AUTOMATIC); + if (!i2c->last_msg) + i2c->int_enable |= INT_SLAVE_EVENT; + + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); + img_i2c_writel(i2c, SCB_READ_ADDR_REG, i2c->msg.addr); + img_i2c_writel(i2c, SCB_READ_COUNT_REG, i2c->msg.len); + + mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1)); +} + +/* Start a write transaction in automatic mode */ +static void img_i2c_write(struct img_i2c *i2c) +{ + img_i2c_switch_mode(i2c, MODE_AUTOMATIC); + if (!i2c->last_msg) + i2c->int_enable |= INT_SLAVE_EVENT; + + img_i2c_writel(i2c, SCB_WRITE_ADDR_REG, i2c->msg.addr); + img_i2c_writel(i2c, SCB_WRITE_COUNT_REG, i2c->msg.len); + + mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1)); + img_i2c_write_fifo(i2c); + + /* img_i2c_write_fifo() may modify int_enable */ + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); +} + +/* + * Indicate that the transaction is complete. This is called from the + * ISR to wake up the waiting thread, after which the ISR must not + * access any more SCB registers. + */ +static void img_i2c_complete_transaction(struct img_i2c *i2c, int status) +{ + img_i2c_switch_mode(i2c, MODE_INACTIVE); + if (status) { + i2c->msg_status = status; + img_i2c_transaction_halt(i2c, false); + } + complete(&i2c->msg_complete); +} + +static unsigned int img_i2c_raw_atomic_delay_handler(struct img_i2c *i2c, + u32 int_status, u32 line_status) +{ + /* Stay in raw mode for this, so we don't just loop infinitely */ + img_i2c_atomic_op(i2c, i2c->at_cur_cmd, i2c->at_cur_data); + img_i2c_switch_mode(i2c, MODE_ATOMIC); + return 0; +} + +static unsigned int img_i2c_raw(struct img_i2c *i2c, u32 int_status, + u32 line_status) +{ + if (int_status & INT_TIMING) { + if (i2c->raw_timeout == 0) + return img_i2c_raw_atomic_delay_handler(i2c, + int_status, line_status); + --i2c->raw_timeout; + } + return 0; +} + +static unsigned int img_i2c_sequence(struct img_i2c *i2c, u32 int_status) +{ + static const unsigned int continue_bits[] = { + [CMD_GEN_START] = LINESTAT_START_BIT_DET, + [CMD_GEN_DATA] = LINESTAT_INPUT_HELD_V, + [CMD_RET_ACK] = LINESTAT_ACK_DET | LINESTAT_NACK_DET, + [CMD_RET_DATA] = LINESTAT_INPUT_HELD_V, + [CMD_GEN_STOP] = LINESTAT_STOP_BIT_DET, + }; + int next_cmd = -1; + u8 next_data = 0x00; + + if (int_status & INT_SLAVE_EVENT) + i2c->at_slave_event = true; + if (int_status & INT_TRANSACTION_DONE) + i2c->at_t_done = true; + + if (!i2c->at_slave_event || !i2c->at_t_done) + return 0; + + /* wait if no continue bits are set */ + if (i2c->at_cur_cmd >= 0 && + i2c->at_cur_cmd < ARRAY_SIZE(continue_bits)) { + unsigned int cont_bits = continue_bits[i2c->at_cur_cmd]; + + if (cont_bits) { + cont_bits |= LINESTAT_ABORT_DET; + if (!(i2c->line_status & cont_bits)) + return 0; + } + } + + /* follow the sequence of commands in i2c->seq */ + next_cmd = *i2c->seq; + /* stop on a nil */ + if (!next_cmd) { + img_i2c_writel(i2c, SCB_OVERRIDE_REG, 0); + return ISR_COMPLETE(0); + } + /* when generating data, the next byte is the data */ + if (next_cmd == CMD_GEN_DATA) { + ++i2c->seq; + next_data = *i2c->seq; + } + ++i2c->seq; + img_i2c_atomic_op(i2c, next_cmd, next_data); + + return 0; +} + +static void img_i2c_reset_start(struct img_i2c *i2c) +{ + /* Initiate the magic dance */ + img_i2c_switch_mode(i2c, MODE_SEQUENCE); + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); + i2c->seq = img_i2c_reset_seq; + i2c->at_slave_event = true; + i2c->at_t_done = true; + i2c->at_cur_cmd = -1; + + /* img_i2c_reset_seq isn't empty so the following won't fail */ + img_i2c_sequence(i2c, 0); +} + +static void img_i2c_stop_start(struct img_i2c *i2c) +{ + /* Initiate a stop bit sequence */ + img_i2c_switch_mode(i2c, MODE_SEQUENCE); + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); + i2c->seq = img_i2c_stop_seq; + i2c->at_slave_event = true; + i2c->at_t_done = true; + i2c->at_cur_cmd = -1; + + /* img_i2c_stop_seq isn't empty so the following won't fail */ + img_i2c_sequence(i2c, 0); +} + +static unsigned int img_i2c_atomic(struct img_i2c *i2c, + u32 int_status, + u32 line_status) +{ + int next_cmd = -1; + u8 next_data = 0x00; + + if (int_status & INT_SLAVE_EVENT) + i2c->at_slave_event = true; + if (int_status & INT_TRANSACTION_DONE) + i2c->at_t_done = true; + + if (!i2c->at_slave_event || !i2c->at_t_done) + goto next_atomic_cmd; + if (i2c->line_status & LINESTAT_ABORT_DET) { + dev_dbg(i2c->adap.dev.parent, "abort condition detected\n"); + next_cmd = CMD_GEN_STOP; + i2c->msg_status = -EIO; + goto next_atomic_cmd; + } + + /* i2c->at_cur_cmd may have completed */ + switch (i2c->at_cur_cmd) { + case CMD_GEN_START: + next_cmd = CMD_GEN_DATA; + next_data = i2c_8bit_addr_from_msg(&i2c->msg); + break; + case CMD_GEN_DATA: + if (i2c->line_status & LINESTAT_INPUT_HELD_V) + next_cmd = CMD_RET_ACK; + break; + case CMD_RET_ACK: + if (i2c->line_status & LINESTAT_ACK_DET || + (i2c->line_status & LINESTAT_NACK_DET && + i2c->msg.flags & I2C_M_IGNORE_NAK)) { + if (i2c->msg.len == 0) { + next_cmd = CMD_GEN_STOP; + } else if (i2c->msg.flags & I2C_M_RD) { + next_cmd = CMD_RET_DATA; + } else { + next_cmd = CMD_GEN_DATA; + next_data = *i2c->msg.buf; + --i2c->msg.len; + ++i2c->msg.buf; + } + } else if (i2c->line_status & LINESTAT_NACK_DET) { + i2c->msg_status = -EIO; + next_cmd = CMD_GEN_STOP; + } + break; + case CMD_RET_DATA: + if (i2c->line_status & LINESTAT_INPUT_HELD_V) { + *i2c->msg.buf = (i2c->line_status & + LINESTAT_INPUT_DATA) + >> LINESTAT_INPUT_DATA_SHIFT; + --i2c->msg.len; + ++i2c->msg.buf; + if (i2c->msg.len) + next_cmd = CMD_GEN_ACK; + else + next_cmd = CMD_GEN_NACK; + } + break; + case CMD_GEN_ACK: + if (i2c->line_status & LINESTAT_ACK_DET) { + next_cmd = CMD_RET_DATA; + } else { + i2c->msg_status = -EIO; + next_cmd = CMD_GEN_STOP; + } + break; + case CMD_GEN_NACK: + next_cmd = CMD_GEN_STOP; + break; + case CMD_GEN_STOP: + img_i2c_writel(i2c, SCB_OVERRIDE_REG, 0); + return ISR_COMPLETE(0); + default: + dev_err(i2c->adap.dev.parent, "bad atomic command %d\n", + i2c->at_cur_cmd); + i2c->msg_status = -EIO; + next_cmd = CMD_GEN_STOP; + break; + } + +next_atomic_cmd: + if (next_cmd != -1) { + /* don't actually stop unless we're the last transaction */ + if (next_cmd == CMD_GEN_STOP && !i2c->msg_status && + !i2c->last_msg) + return ISR_COMPLETE(0); + img_i2c_atomic_op(i2c, next_cmd, next_data); + } + return 0; +} + +/* + * Timer function to check if something has gone wrong in automatic mode (so we + * don't have to handle so many interrupts just to catch an exception). + */ +static void img_i2c_check_timer(struct timer_list *t) +{ + struct img_i2c *i2c = from_timer(i2c, t, check_timer); + unsigned long flags; + unsigned int line_status; + + spin_lock_irqsave(&i2c->lock, flags); + line_status = img_i2c_readl(i2c, SCB_STATUS_REG); + + /* check for an abort condition */ + if (line_status & LINESTAT_ABORT_DET) { + dev_dbg(i2c->adap.dev.parent, + "abort condition detected by check timer\n"); + /* enable slave event interrupt mask to trigger irq */ + img_i2c_writel(i2c, SCB_INT_MASK_REG, + i2c->int_enable | INT_SLAVE_EVENT); + } + + spin_unlock_irqrestore(&i2c->lock, flags); +} + +static unsigned int img_i2c_auto(struct img_i2c *i2c, + unsigned int int_status, + unsigned int line_status) +{ + if (int_status & (INT_WRITE_ACK_ERR | INT_ADDR_ACK_ERR)) + return ISR_COMPLETE(EIO); + + if (line_status & LINESTAT_ABORT_DET) { + dev_dbg(i2c->adap.dev.parent, "abort condition detected\n"); + /* empty the read fifo */ + if ((i2c->msg.flags & I2C_M_RD) && + (int_status & INT_FIFO_FULL_FILLING)) + img_i2c_read_fifo(i2c); + /* use atomic mode and try to force a stop bit */ + i2c->msg_status = -EIO; + img_i2c_stop_start(i2c); + return 0; + } + + /* Enable transaction halt on start bit */ + if (!i2c->last_msg && line_status & LINESTAT_START_BIT_DET) { + img_i2c_transaction_halt(i2c, !i2c->last_msg); + /* we're no longer interested in the slave event */ + i2c->int_enable &= ~INT_SLAVE_EVENT; + } + + mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1)); + + if (int_status & INT_STOP_DETECTED) { + /* Drain remaining data in FIFO and complete transaction */ + if (i2c->msg.flags & I2C_M_RD) + img_i2c_read_fifo(i2c); + return ISR_COMPLETE(0); + } + + if (i2c->msg.flags & I2C_M_RD) { + if (int_status & (INT_FIFO_FULL_FILLING | INT_MASTER_HALTED)) { + img_i2c_read_fifo(i2c); + if (i2c->msg.len == 0) + return ISR_WAITSTOP; + } + } else { + if (int_status & (INT_FIFO_EMPTY | INT_MASTER_HALTED)) { + if ((int_status & INT_FIFO_EMPTY) && + i2c->msg.len == 0) + return ISR_WAITSTOP; + img_i2c_write_fifo(i2c); + } + } + if (int_status & INT_MASTER_HALTED) { + /* + * Release and then enable transaction halt, to + * allow only a single byte to proceed. + */ + img_i2c_transaction_halt(i2c, false); + img_i2c_transaction_halt(i2c, !i2c->last_msg); + } + + return 0; +} + +static irqreturn_t img_i2c_isr(int irq, void *dev_id) +{ + struct img_i2c *i2c = (struct img_i2c *)dev_id; + u32 int_status, line_status; + /* We handle transaction completion AFTER accessing registers */ + unsigned int hret; + + /* Read interrupt status register. */ + int_status = img_i2c_readl(i2c, SCB_INT_STATUS_REG); + /* Clear detected interrupts. */ + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, int_status); + + /* + * Read line status and clear it until it actually is clear. We have + * to be careful not to lose any line status bits that get latched. + */ + line_status = img_i2c_readl(i2c, SCB_STATUS_REG); + if (line_status & LINESTAT_LATCHED) { + img_i2c_writel(i2c, SCB_CLEAR_REG, + (line_status & LINESTAT_LATCHED) + >> LINESTAT_CLEAR_SHIFT); + img_i2c_wr_rd_fence(i2c); + } + + spin_lock(&i2c->lock); + + /* Keep track of line status bits received */ + i2c->line_status &= ~LINESTAT_INPUT_DATA; + i2c->line_status |= line_status; + + /* + * Certain interrupts indicate that sclk low timeout is not + * a problem. If any of these are set, just continue. + */ + if ((int_status & INT_SCLK_LOW_TIMEOUT) && + !(int_status & (INT_SLAVE_EVENT | + INT_FIFO_EMPTY | + INT_FIFO_FULL))) { + dev_crit(i2c->adap.dev.parent, + "fatal: clock low timeout occurred %s addr 0x%02x\n", + (i2c->msg.flags & I2C_M_RD) ? "reading" : "writing", + i2c->msg.addr); + hret = ISR_FATAL(EIO); + goto out; + } + + if (i2c->mode == MODE_ATOMIC) + hret = img_i2c_atomic(i2c, int_status, line_status); + else if (i2c->mode == MODE_AUTOMATIC) + hret = img_i2c_auto(i2c, int_status, line_status); + else if (i2c->mode == MODE_SEQUENCE) + hret = img_i2c_sequence(i2c, int_status); + else if (i2c->mode == MODE_WAITSTOP && (int_status & INT_SLAVE_EVENT) && + (line_status & LINESTAT_STOP_BIT_DET)) + hret = ISR_COMPLETE(0); + else if (i2c->mode == MODE_RAW) + hret = img_i2c_raw(i2c, int_status, line_status); + else + hret = 0; + + /* Clear detected level interrupts. */ + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, int_status & INT_LEVEL); + +out: + if (hret & ISR_WAITSTOP) { + /* + * Only wait for stop on last message. + * Also we may already have detected the stop bit. + */ + if (!i2c->last_msg || i2c->line_status & LINESTAT_STOP_BIT_DET) + hret = ISR_COMPLETE(0); + else + img_i2c_switch_mode(i2c, MODE_WAITSTOP); + } + + /* now we've finished using regs, handle transaction completion */ + if (hret & ISR_COMPLETE_M) { + int status = -(hret & ISR_STATUS_M); + + img_i2c_complete_transaction(i2c, status); + if (hret & ISR_FATAL_M) + img_i2c_switch_mode(i2c, MODE_FATAL); + } + + /* Enable interrupts (int_enable may be altered by changing mode) */ + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); + + spin_unlock(&i2c->lock); + + return IRQ_HANDLED; +} + +/* Force a bus reset sequence and wait for it to complete */ +static int img_i2c_reset_bus(struct img_i2c *i2c) +{ + unsigned long flags; + unsigned long time_left; + + spin_lock_irqsave(&i2c->lock, flags); + reinit_completion(&i2c->msg_complete); + img_i2c_reset_start(i2c); + spin_unlock_irqrestore(&i2c->lock, flags); + + time_left = wait_for_completion_timeout(&i2c->msg_complete, + IMG_I2C_TIMEOUT); + if (time_left == 0) + return -ETIMEDOUT; + return 0; +} + +static int img_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct img_i2c *i2c = i2c_get_adapdata(adap); + bool atomic = false; + int i, ret; + unsigned long time_left; + + if (i2c->mode == MODE_SUSPEND) { + WARN(1, "refusing to service transaction in suspended state\n"); + return -EIO; + } + + if (i2c->mode == MODE_FATAL) + return -EIO; + + for (i = 0; i < num; i++) { + /* + * 0 byte reads are not possible because the slave could try + * and pull the data line low, preventing a stop bit. + */ + if (!msgs[i].len && msgs[i].flags & I2C_M_RD) + return -EIO; + /* + * 0 byte writes are possible and used for probing, but we + * cannot do them in automatic mode, so use atomic mode + * instead. + * + * Also, the I2C_M_IGNORE_NAK mode can only be implemented + * in atomic mode. + */ + if (!msgs[i].len || + (msgs[i].flags & I2C_M_IGNORE_NAK)) + atomic = true; + } + + ret = pm_runtime_get_sync(adap->dev.parent); + if (ret < 0) + return ret; + + for (i = 0; i < num; i++) { + struct i2c_msg *msg = &msgs[i]; + unsigned long flags; + + spin_lock_irqsave(&i2c->lock, flags); + + /* + * Make a copy of the message struct. We mustn't modify the + * original or we'll confuse drivers and i2c-dev. + */ + i2c->msg = *msg; + i2c->msg_status = 0; + + /* + * After the last message we must have waited for a stop bit. + * Not waiting can cause problems when the clock is disabled + * before the stop bit is sent, and the linux I2C interface + * requires separate transfers not to joined with repeated + * start. + */ + i2c->last_msg = (i == num - 1); + reinit_completion(&i2c->msg_complete); + + /* + * Clear line status and all interrupts before starting a + * transfer, as we may have unserviced interrupts from + * previous transfers that might be handled in the context + * of the new transfer. + */ + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, ~0); + img_i2c_writel(i2c, SCB_CLEAR_REG, ~0); + + if (atomic) { + img_i2c_atomic_start(i2c); + } else { + /* + * Enable transaction halt if not the last message in + * the queue so that we can control repeated starts. + */ + img_i2c_transaction_halt(i2c, !i2c->last_msg); + + if (msg->flags & I2C_M_RD) + img_i2c_read(i2c); + else + img_i2c_write(i2c); + + /* + * Release and then enable transaction halt, to + * allow only a single byte to proceed. + * This doesn't have an effect on the initial transfer + * but will allow the following transfers to start + * processing if the previous transfer was marked as + * complete while the i2c block was halted. + */ + img_i2c_transaction_halt(i2c, false); + img_i2c_transaction_halt(i2c, !i2c->last_msg); + } + spin_unlock_irqrestore(&i2c->lock, flags); + + time_left = wait_for_completion_timeout(&i2c->msg_complete, + IMG_I2C_TIMEOUT); + del_timer_sync(&i2c->check_timer); + + if (time_left == 0) { + dev_err(adap->dev.parent, "i2c transfer timed out\n"); + i2c->msg_status = -ETIMEDOUT; + break; + } + + if (i2c->msg_status) + break; + } + + pm_runtime_mark_last_busy(adap->dev.parent); + pm_runtime_put_autosuspend(adap->dev.parent); + + return i2c->msg_status ? i2c->msg_status : num; +} + +static u32 img_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm img_i2c_algo = { + .master_xfer = img_i2c_xfer, + .functionality = img_i2c_func, +}; + +static int img_i2c_init(struct img_i2c *i2c) +{ + unsigned int clk_khz, bitrate_khz, clk_period, tckh, tckl, tsdh; + unsigned int i, data, prescale, inc, int_bitrate, filt; + struct img_i2c_timings timing; + u32 rev; + int ret; + + ret = pm_runtime_get_sync(i2c->adap.dev.parent); + if (ret < 0) + return ret; + + rev = img_i2c_readl(i2c, SCB_CORE_REV_REG); + if ((rev & 0x00ffffff) < 0x00020200) { + dev_info(i2c->adap.dev.parent, + "Unknown hardware revision (%d.%d.%d.%d)\n", + (rev >> 24) & 0xff, (rev >> 16) & 0xff, + (rev >> 8) & 0xff, rev & 0xff); + pm_runtime_mark_last_busy(i2c->adap.dev.parent); + pm_runtime_put_autosuspend(i2c->adap.dev.parent); + return -EINVAL; + } + + /* Fencing enabled by default. */ + i2c->need_wr_rd_fence = true; + + /* Determine what mode we're in from the bitrate */ + timing = timings[0]; + for (i = 0; i < ARRAY_SIZE(timings); i++) { + if (i2c->bitrate <= timings[i].max_bitrate) { + timing = timings[i]; + break; + } + } + if (i2c->bitrate > timings[ARRAY_SIZE(timings) - 1].max_bitrate) { + dev_warn(i2c->adap.dev.parent, + "requested bitrate (%u) is higher than the max bitrate supported (%u)\n", + i2c->bitrate, + timings[ARRAY_SIZE(timings) - 1].max_bitrate); + timing = timings[ARRAY_SIZE(timings) - 1]; + i2c->bitrate = timing.max_bitrate; + } + + bitrate_khz = i2c->bitrate / 1000; + clk_khz = clk_get_rate(i2c->scb_clk) / 1000; + + /* Find the prescale that would give us that inc (approx delay = 0) */ + prescale = SCB_OPT_INC * clk_khz / (256 * 16 * bitrate_khz); + prescale = clamp_t(unsigned int, prescale, 1, 8); + clk_khz /= prescale; + + /* Setup the clock increment value */ + inc = (256 * 16 * bitrate_khz) / clk_khz; + + /* + * The clock generation logic allows to filter glitches on the bus. + * This filter is able to remove bus glitches shorter than 50ns. + * If the clock enable rate is greater than 20 MHz, no filtering + * is required, so we need to disable it. + * If it's between the 20-40 MHz range, there's no need to divide + * the clock to get a filter. + */ + if (clk_khz < 20000) { + filt = SCB_FILT_DISABLE; + } else if (clk_khz < 40000) { + filt = SCB_FILT_BYPASS; + } else { + /* Calculate filter clock */ + filt = (64000 / ((clk_khz / 1000) * SCB_FILT_GLITCH)); + + /* Scale up if needed */ + if (64000 % ((clk_khz / 1000) * SCB_FILT_GLITCH)) + inc++; + + if (filt > SCB_FILT_INC_MASK) + filt = SCB_FILT_INC_MASK; + + filt = (filt & SCB_FILT_INC_MASK) << SCB_FILT_INC_SHIFT; + } + data = filt | ((inc & SCB_INC_MASK) << SCB_INC_SHIFT) | (prescale - 1); + img_i2c_writel(i2c, SCB_CLK_SET_REG, data); + + /* Obtain the clock period of the fx16 clock in ns */ + clk_period = (256 * 1000000) / (clk_khz * inc); + + /* Calculate the bitrate in terms of internal clock pulses */ + int_bitrate = 1000000 / (bitrate_khz * clk_period); + if ((1000000 % (bitrate_khz * clk_period)) >= + ((bitrate_khz * clk_period) / 2)) + int_bitrate++; + + /* + * Setup clock duty cycle, start with 50% and adjust TCKH and TCKL + * values from there if they don't meet minimum timing requirements + */ + tckh = int_bitrate / 2; + tckl = int_bitrate - tckh; + + /* Adjust TCKH and TCKL values */ + data = DIV_ROUND_UP(timing.tckl, clk_period); + + if (tckl < data) { + tckl = data; + tckh = int_bitrate - tckl; + } + + if (tckh > 0) + --tckh; + + if (tckl > 0) + --tckl; + + img_i2c_writel(i2c, SCB_TIME_TCKH_REG, tckh); + img_i2c_writel(i2c, SCB_TIME_TCKL_REG, tckl); + + /* Setup TSDH value */ + tsdh = DIV_ROUND_UP(timing.tsdh, clk_period); + + if (tsdh > 1) + data = tsdh - 1; + else + data = 0x01; + img_i2c_writel(i2c, SCB_TIME_TSDH_REG, data); + + /* This value is used later */ + tsdh = data; + + /* Setup TPL value */ + data = timing.tpl / clk_period; + if (data > 0) + --data; + img_i2c_writel(i2c, SCB_TIME_TPL_REG, data); + + /* Setup TPH value */ + data = timing.tph / clk_period; + if (data > 0) + --data; + img_i2c_writel(i2c, SCB_TIME_TPH_REG, data); + + /* Setup TSDL value to TPL + TSDH + 2 */ + img_i2c_writel(i2c, SCB_TIME_TSDL_REG, data + tsdh + 2); + + /* Setup TP2S value */ + data = timing.tp2s / clk_period; + if (data > 0) + --data; + img_i2c_writel(i2c, SCB_TIME_TP2S_REG, data); + + img_i2c_writel(i2c, SCB_TIME_TBI_REG, TIMEOUT_TBI); + img_i2c_writel(i2c, SCB_TIME_TSL_REG, TIMEOUT_TSL); + img_i2c_writel(i2c, SCB_TIME_TDL_REG, TIMEOUT_TDL); + + /* Take module out of soft reset and enable clocks */ + img_i2c_soft_reset(i2c); + + /* Disable all interrupts */ + img_i2c_writel(i2c, SCB_INT_MASK_REG, 0); + + /* Clear all interrupts */ + img_i2c_writel(i2c, SCB_INT_CLEAR_REG, ~0); + + /* Clear the scb_line_status events */ + img_i2c_writel(i2c, SCB_CLEAR_REG, ~0); + + /* Enable interrupts */ + img_i2c_writel(i2c, SCB_INT_MASK_REG, i2c->int_enable); + + /* Perform a synchronous sequence to reset the bus */ + ret = img_i2c_reset_bus(i2c); + + pm_runtime_mark_last_busy(i2c->adap.dev.parent); + pm_runtime_put_autosuspend(i2c->adap.dev.parent); + + return ret; +} + +static int img_i2c_probe(struct platform_device *pdev) +{ + struct device_node *node = pdev->dev.of_node; + struct img_i2c *i2c; + struct resource *res; + int irq, ret; + u32 val; + + i2c = devm_kzalloc(&pdev->dev, sizeof(struct img_i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + i2c->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(i2c->base)) + return PTR_ERR(i2c->base); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "can't get irq number\n"); + return irq; + } + + i2c->sys_clk = devm_clk_get(&pdev->dev, "sys"); + if (IS_ERR(i2c->sys_clk)) { + dev_err(&pdev->dev, "can't get system clock\n"); + return PTR_ERR(i2c->sys_clk); + } + + i2c->scb_clk = devm_clk_get(&pdev->dev, "scb"); + if (IS_ERR(i2c->scb_clk)) { + dev_err(&pdev->dev, "can't get core clock\n"); + return PTR_ERR(i2c->scb_clk); + } + + ret = devm_request_irq(&pdev->dev, irq, img_i2c_isr, 0, + pdev->name, i2c); + if (ret) { + dev_err(&pdev->dev, "can't request irq %d\n", irq); + return ret; + } + + /* Set up the exception check timer */ + timer_setup(&i2c->check_timer, img_i2c_check_timer, 0); + + i2c->bitrate = timings[0].max_bitrate; + if (!of_property_read_u32(node, "clock-frequency", &val)) + i2c->bitrate = val; + + i2c_set_adapdata(&i2c->adap, i2c); + i2c->adap.dev.parent = &pdev->dev; + i2c->adap.dev.of_node = node; + i2c->adap.owner = THIS_MODULE; + i2c->adap.algo = &img_i2c_algo; + i2c->adap.retries = 5; + i2c->adap.nr = pdev->id; + snprintf(i2c->adap.name, sizeof(i2c->adap.name), "IMG SCB I2C"); + + img_i2c_switch_mode(i2c, MODE_INACTIVE); + spin_lock_init(&i2c->lock); + init_completion(&i2c->msg_complete); + + platform_set_drvdata(pdev, i2c); + + pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_I2C_PM_TIMEOUT); + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_enable(&pdev->dev); + if (!pm_runtime_enabled(&pdev->dev)) { + ret = img_i2c_runtime_resume(&pdev->dev); + if (ret) + return ret; + } + + ret = img_i2c_init(i2c); + if (ret) + goto rpm_disable; + + ret = i2c_add_numbered_adapter(&i2c->adap); + if (ret < 0) + goto rpm_disable; + + return 0; + +rpm_disable: + if (!pm_runtime_enabled(&pdev->dev)) + img_i2c_runtime_suspend(&pdev->dev); + pm_runtime_disable(&pdev->dev); + pm_runtime_dont_use_autosuspend(&pdev->dev); + return ret; +} + +static int img_i2c_remove(struct platform_device *dev) +{ + struct img_i2c *i2c = platform_get_drvdata(dev); + + i2c_del_adapter(&i2c->adap); + pm_runtime_disable(&dev->dev); + if (!pm_runtime_status_suspended(&dev->dev)) + img_i2c_runtime_suspend(&dev->dev); + + return 0; +} + +static int img_i2c_runtime_suspend(struct device *dev) +{ + struct img_i2c *i2c = dev_get_drvdata(dev); + + clk_disable_unprepare(i2c->scb_clk); + clk_disable_unprepare(i2c->sys_clk); + + return 0; +} + +static int img_i2c_runtime_resume(struct device *dev) +{ + struct img_i2c *i2c = dev_get_drvdata(dev); + int ret; + + ret = clk_prepare_enable(i2c->sys_clk); + if (ret) { + dev_err(dev, "Unable to enable sys clock\n"); + return ret; + } + + ret = clk_prepare_enable(i2c->scb_clk); + if (ret) { + dev_err(dev, "Unable to enable scb clock\n"); + clk_disable_unprepare(i2c->sys_clk); + return ret; + } + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int img_i2c_suspend(struct device *dev) +{ + struct img_i2c *i2c = dev_get_drvdata(dev); + int ret; + + ret = pm_runtime_force_suspend(dev); + if (ret) + return ret; + + img_i2c_switch_mode(i2c, MODE_SUSPEND); + + return 0; +} + +static int img_i2c_resume(struct device *dev) +{ + struct img_i2c *i2c = dev_get_drvdata(dev); + int ret; + + ret = pm_runtime_force_resume(dev); + if (ret) + return ret; + + img_i2c_init(i2c); + + return 0; +} +#endif /* CONFIG_PM_SLEEP */ + +static const struct dev_pm_ops img_i2c_pm = { + SET_RUNTIME_PM_OPS(img_i2c_runtime_suspend, + img_i2c_runtime_resume, + NULL) + SET_SYSTEM_SLEEP_PM_OPS(img_i2c_suspend, img_i2c_resume) +}; + +static const struct of_device_id img_scb_i2c_match[] = { + { .compatible = "img,scb-i2c" }, + { } +}; +MODULE_DEVICE_TABLE(of, img_scb_i2c_match); + +static struct platform_driver img_scb_i2c_driver = { + .driver = { + .name = "img-i2c-scb", + .of_match_table = img_scb_i2c_match, + .pm = &img_i2c_pm, + }, + .probe = img_i2c_probe, + .remove = img_i2c_remove, +}; +module_platform_driver(img_scb_i2c_driver); + +MODULE_AUTHOR("James Hogan <jhogan@kernel.org>"); +MODULE_DESCRIPTION("IMG host I2C driver"); +MODULE_LICENSE("GPL v2"); |