AcoSail/kernel_optimize_test
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kernel_optimize_test/drivers/i2c/busses/i2c-exynos5.c
Andrzej Hajda 939c5a46e5 i2c: exynos5: rework HSI2C_MASTER_ST_LOSE state handling 
HSI2C_MASTER_ST_LOSE state is not documented properly, extensive tests
show that hardware is usually able to recover from this state without
interrupting the transfer. Moreover documentation says that
such state can be caused by slave clock stretching, and should not be
treated as an error during transaction. The only place it indicates
an error is just before starting transaction. In such case bus recovery
procedure should be performed - master should pulse SCL line nine times
and then send STOP condition, it can be repeated until SDA goes high.
The procedure can be performed using manual commands HSI2C_CMD_READ_DATA
and HSI2C_CMD_SEND_STOP.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-02-27 13:47:28 +01:00

910 lines
24 KiB
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/**
* i2c-exynos5.c - Samsung Exynos5 I2C Controller Driver
*
* Copyright (C) 2013 Samsung Electronics Co., 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.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/spinlock.h>
/*
* HSI2C controller from Samsung supports 2 modes of operation
* 1. Auto mode: Where in master automatically controls the whole transaction
* 2. Manual mode: Software controls the transaction by issuing commands
* START, READ, WRITE, STOP, RESTART in I2C_MANUAL_CMD register.
*
* Operation mode can be selected by setting AUTO_MODE bit in I2C_CONF register
*
* Special bits are available for both modes of operation to set commands
* and for checking transfer status
*/
/* Register Map */
#define HSI2C_CTL 0x00
#define HSI2C_FIFO_CTL 0x04
#define HSI2C_TRAILIG_CTL 0x08
#define HSI2C_CLK_CTL 0x0C
#define HSI2C_CLK_SLOT 0x10
#define HSI2C_INT_ENABLE 0x20
#define HSI2C_INT_STATUS 0x24
#define HSI2C_ERR_STATUS 0x2C
#define HSI2C_FIFO_STATUS 0x30
#define HSI2C_TX_DATA 0x34
#define HSI2C_RX_DATA 0x38
#define HSI2C_CONF 0x40
#define HSI2C_AUTO_CONF 0x44
#define HSI2C_TIMEOUT 0x48
#define HSI2C_MANUAL_CMD 0x4C
#define HSI2C_TRANS_STATUS 0x50
#define HSI2C_TIMING_HS1 0x54
#define HSI2C_TIMING_HS2 0x58
#define HSI2C_TIMING_HS3 0x5C
#define HSI2C_TIMING_FS1 0x60
#define HSI2C_TIMING_FS2 0x64
#define HSI2C_TIMING_FS3 0x68
#define HSI2C_TIMING_SLA 0x6C
#define HSI2C_ADDR 0x70
/* I2C_CTL Register bits */
#define HSI2C_FUNC_MODE_I2C (1u << 0)
#define HSI2C_MASTER (1u << 3)
#define HSI2C_RXCHON (1u << 6)
#define HSI2C_TXCHON (1u << 7)
#define HSI2C_SW_RST (1u << 31)
/* I2C_FIFO_CTL Register bits */
#define HSI2C_RXFIFO_EN (1u << 0)
#define HSI2C_TXFIFO_EN (1u << 1)
#define HSI2C_RXFIFO_TRIGGER_LEVEL(x) ((x) << 4)
#define HSI2C_TXFIFO_TRIGGER_LEVEL(x) ((x) << 16)
/* I2C_TRAILING_CTL Register bits */
#define HSI2C_TRAILING_COUNT (0xf)
/* I2C_INT_EN Register bits */
#define HSI2C_INT_TX_ALMOSTEMPTY_EN (1u << 0)
#define HSI2C_INT_RX_ALMOSTFULL_EN (1u << 1)
#define HSI2C_INT_TRAILING_EN (1u << 6)
/* I2C_INT_STAT Register bits */
#define HSI2C_INT_TX_ALMOSTEMPTY (1u << 0)
#define HSI2C_INT_RX_ALMOSTFULL (1u << 1)
#define HSI2C_INT_TX_UNDERRUN (1u << 2)
#define HSI2C_INT_TX_OVERRUN (1u << 3)
#define HSI2C_INT_RX_UNDERRUN (1u << 4)
#define HSI2C_INT_RX_OVERRUN (1u << 5)
#define HSI2C_INT_TRAILING (1u << 6)
#define HSI2C_INT_I2C (1u << 9)
#define HSI2C_INT_TRANS_DONE (1u << 7)
#define HSI2C_INT_TRANS_ABORT (1u << 8)
#define HSI2C_INT_NO_DEV_ACK (1u << 9)
#define HSI2C_INT_NO_DEV (1u << 10)
#define HSI2C_INT_TIMEOUT (1u << 11)
#define HSI2C_INT_I2C_TRANS (HSI2C_INT_TRANS_DONE | \
HSI2C_INT_TRANS_ABORT | \
HSI2C_INT_NO_DEV_ACK | \
HSI2C_INT_NO_DEV | \
HSI2C_INT_TIMEOUT)
/* I2C_FIFO_STAT Register bits */
#define HSI2C_RX_FIFO_EMPTY (1u << 24)
#define HSI2C_RX_FIFO_FULL (1u << 23)
#define HSI2C_RX_FIFO_LVL(x) ((x >> 16) & 0x7f)
#define HSI2C_TX_FIFO_EMPTY (1u << 8)
#define HSI2C_TX_FIFO_FULL (1u << 7)
#define HSI2C_TX_FIFO_LVL(x) ((x >> 0) & 0x7f)
/* I2C_CONF Register bits */
#define HSI2C_AUTO_MODE (1u << 31)
#define HSI2C_10BIT_ADDR_MODE (1u << 30)
#define HSI2C_HS_MODE (1u << 29)
/* I2C_AUTO_CONF Register bits */
#define HSI2C_READ_WRITE (1u << 16)
#define HSI2C_STOP_AFTER_TRANS (1u << 17)
#define HSI2C_MASTER_RUN (1u << 31)
/* I2C_TIMEOUT Register bits */
#define HSI2C_TIMEOUT_EN (1u << 31)
#define HSI2C_TIMEOUT_MASK 0xff
/* I2C_MANUAL_CMD register bits */
#define HSI2C_CMD_READ_DATA (1u << 4)
#define HSI2C_CMD_SEND_STOP (1u << 2)
/* I2C_TRANS_STATUS register bits */
#define HSI2C_MASTER_BUSY (1u << 17)
#define HSI2C_SLAVE_BUSY (1u << 16)
/* I2C_TRANS_STATUS register bits for Exynos5 variant */
#define HSI2C_TIMEOUT_AUTO (1u << 4)
#define HSI2C_NO_DEV (1u << 3)
#define HSI2C_NO_DEV_ACK (1u << 2)
#define HSI2C_TRANS_ABORT (1u << 1)
#define HSI2C_TRANS_DONE (1u << 0)
/* I2C_TRANS_STATUS register bits for Exynos7 variant */
#define HSI2C_MASTER_ST_MASK 0xf
#define HSI2C_MASTER_ST_IDLE 0x0
#define HSI2C_MASTER_ST_START 0x1
#define HSI2C_MASTER_ST_RESTART 0x2
#define HSI2C_MASTER_ST_STOP 0x3
#define HSI2C_MASTER_ST_MASTER_ID 0x4
#define HSI2C_MASTER_ST_ADDR0 0x5
#define HSI2C_MASTER_ST_ADDR1 0x6
#define HSI2C_MASTER_ST_ADDR2 0x7
#define HSI2C_MASTER_ST_ADDR_SR 0x8
#define HSI2C_MASTER_ST_READ 0x9
#define HSI2C_MASTER_ST_WRITE 0xa
#define HSI2C_MASTER_ST_NO_ACK 0xb
#define HSI2C_MASTER_ST_LOSE 0xc
#define HSI2C_MASTER_ST_WAIT 0xd
#define HSI2C_MASTER_ST_WAIT_CMD 0xe
/* I2C_ADDR register bits */
#define HSI2C_SLV_ADDR_SLV(x) ((x & 0x3ff) << 0)
#define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10)
#define HSI2C_MASTER_ID(x) ((x & 0xff) << 24)
#define MASTER_ID(x) ((x & 0x7) + 0x08)
/*
* Controller operating frequency, timing values for operation
* are calculated against this frequency
*/
#define HSI2C_HS_TX_CLOCK 1000000
#define HSI2C_FS_TX_CLOCK 100000
#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(100))
#define HSI2C_EXYNOS7 BIT(0)
struct exynos5_i2c {
struct i2c_adapter adap;
unsigned int suspended:1;
struct i2c_msg *msg;
struct completion msg_complete;
unsigned int msg_ptr;
unsigned int irq;
void __iomem *regs;
struct clk *clk;
struct device *dev;
int state;
spinlock_t lock; /* IRQ synchronization */
/*
* Since the TRANS_DONE bit is cleared on read, and we may read it
* either during an IRQ or after a transaction, keep track of its
* state here.
*/
int trans_done;
/* Controller operating frequency */
unsigned int op_clock;
/* Version of HS-I2C Hardware */
const struct exynos_hsi2c_variant *variant;
};
/**
* struct exynos_hsi2c_variant - platform specific HSI2C driver data
* @fifo_depth: the fifo depth supported by the HSI2C module
*
* Specifies platform specific configuration of HSI2C module.
* Note: A structure for driver specific platform data is used for future
* expansion of its usage.
*/
struct exynos_hsi2c_variant {
unsigned int fifo_depth;
unsigned int hw;
};
static const struct exynos_hsi2c_variant exynos5250_hsi2c_data = {
.fifo_depth = 64,
};
static const struct exynos_hsi2c_variant exynos5260_hsi2c_data = {
.fifo_depth = 16,
};
static const struct exynos_hsi2c_variant exynos7_hsi2c_data = {
.fifo_depth = 16,
.hw = HSI2C_EXYNOS7,
};
static const struct of_device_id exynos5_i2c_match[] = {
{
.compatible = "samsung,exynos5-hsi2c",
.data = &exynos5250_hsi2c_data
}, {
.compatible = "samsung,exynos5250-hsi2c",
.data = &exynos5250_hsi2c_data
}, {
.compatible = "samsung,exynos5260-hsi2c",
.data = &exynos5260_hsi2c_data
}, {
.compatible = "samsung,exynos7-hsi2c",
.data = &exynos7_hsi2c_data
}, {},
};
MODULE_DEVICE_TABLE(of, exynos5_i2c_match);
static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c)
{
writel(readl(i2c->regs + HSI2C_INT_STATUS),
i2c->regs + HSI2C_INT_STATUS);
}
/*
* exynos5_i2c_set_timing: updates the registers with appropriate
* timing values calculated
*
* Returns 0 on success, -EINVAL if the cycle length cannot
* be calculated.
*/
static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings)
{
u32 i2c_timing_s1;
u32 i2c_timing_s2;
u32 i2c_timing_s3;
u32 i2c_timing_sla;
unsigned int t_start_su, t_start_hd;
unsigned int t_stop_su;
unsigned int t_data_su, t_data_hd;
unsigned int t_scl_l, t_scl_h;
unsigned int t_sr_release;
unsigned int t_ftl_cycle;
unsigned int clkin = clk_get_rate(i2c->clk);
unsigned int op_clk = hs_timings ? i2c->op_clock :
(i2c->op_clock >= HSI2C_HS_TX_CLOCK) ? HSI2C_FS_TX_CLOCK :
i2c->op_clock;
int div, clk_cycle, temp;
/*
* In case of HSI2C controller in Exynos5 series
* FPCLK / FI2C =
* (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
*
* In case of HSI2C controllers in Exynos7 series
* FPCLK / FI2C =
* (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + FLT_CYCLE
*
* clk_cycle := TSCLK_L + TSCLK_H
* temp := (CLK_DIV + 1) * (clk_cycle + 2)
*
* Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510
*
*/
t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7;
temp = clkin / op_clk - 8 - t_ftl_cycle;
if (i2c->variant->hw != HSI2C_EXYNOS7)
temp -= t_ftl_cycle;
div = temp / 512;
clk_cycle = temp / (div + 1) - 2;
if (temp < 4 || div >= 256 || clk_cycle < 2) {
dev_err(i2c->dev, "%s clock set-up failed\n",
hs_timings ? "HS" : "FS");
return -EINVAL;
}
t_scl_l = clk_cycle / 2;
t_scl_h = clk_cycle / 2;
t_start_su = t_scl_l;
t_start_hd = t_scl_l;
t_stop_su = t_scl_l;
t_data_su = t_scl_l / 2;
t_data_hd = t_scl_l / 2;
t_sr_release = clk_cycle;
i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8;
i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0;
i2c_timing_s3 = div << 16 | t_sr_release << 0;
i2c_timing_sla = t_data_hd << 0;
dev_dbg(i2c->dev, "tSTART_SU: %X, tSTART_HD: %X, tSTOP_SU: %X\n",
t_start_su, t_start_hd, t_stop_su);
dev_dbg(i2c->dev, "tDATA_SU: %X, tSCL_L: %X, tSCL_H: %X\n",
t_data_su, t_scl_l, t_scl_h);
dev_dbg(i2c->dev, "nClkDiv: %X, tSR_RELEASE: %X\n",
div, t_sr_release);
dev_dbg(i2c->dev, "tDATA_HD: %X\n", t_data_hd);
if (hs_timings) {
writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_HS1);
writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_HS2);
writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3);
} else {
writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_FS1);
writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_FS2);
writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3);
}
writel(i2c_timing_sla, i2c->regs + HSI2C_TIMING_SLA);
return 0;
}
static int exynos5_hsi2c_clock_setup(struct exynos5_i2c *i2c)
{
/* always set Fast Speed timings */
int ret = exynos5_i2c_set_timing(i2c, false);
if (ret < 0 || i2c->op_clock < HSI2C_HS_TX_CLOCK)
return ret;
return exynos5_i2c_set_timing(i2c, true);
}
/*
* exynos5_i2c_init: configures the controller for I2C functionality
* Programs I2C controller for Master mode operation
*/
static void exynos5_i2c_init(struct exynos5_i2c *i2c)
{
u32 i2c_conf = readl(i2c->regs + HSI2C_CONF);
u32 i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT);
/* Clear to disable Timeout */
i2c_timeout &= ~HSI2C_TIMEOUT_EN;
writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT);
writel((HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
i2c->regs + HSI2C_CTL);
writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL);
if (i2c->op_clock >= HSI2C_HS_TX_CLOCK) {
writel(HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)),
i2c->regs + HSI2C_ADDR);
i2c_conf |= HSI2C_HS_MODE;
}
writel(i2c_conf | HSI2C_AUTO_MODE, i2c->regs + HSI2C_CONF);
}
static void exynos5_i2c_reset(struct exynos5_i2c *i2c)
{
u32 i2c_ctl;
/* Set and clear the bit for reset */
i2c_ctl = readl(i2c->regs + HSI2C_CTL);
i2c_ctl |= HSI2C_SW_RST;
writel(i2c_ctl, i2c->regs + HSI2C_CTL);
i2c_ctl = readl(i2c->regs + HSI2C_CTL);
i2c_ctl &= ~HSI2C_SW_RST;
writel(i2c_ctl, i2c->regs + HSI2C_CTL);
/* We don't expect calculations to fail during the run */
exynos5_hsi2c_clock_setup(i2c);
/* Initialize the configure registers */
exynos5_i2c_init(i2c);
}
/*
* exynos5_i2c_irq: top level IRQ servicing routine
*
* INT_STATUS registers gives the interrupt details. Further,
* FIFO_STATUS or TRANS_STATUS registers are to be check for detailed
* state of the bus.
*/
static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
{
struct exynos5_i2c *i2c = dev_id;
u32 fifo_level, int_status, fifo_status, trans_status;
unsigned char byte;
int len = 0;
i2c->state = -EINVAL;
spin_lock(&i2c->lock);
int_status = readl(i2c->regs + HSI2C_INT_STATUS);
writel(int_status, i2c->regs + HSI2C_INT_STATUS);
/* handle interrupt related to the transfer status */
if (i2c->variant->hw == HSI2C_EXYNOS7) {
if (int_status & HSI2C_INT_TRANS_DONE) {
i2c->trans_done = 1;
i2c->state = 0;
} else if (int_status & HSI2C_INT_TRANS_ABORT) {
dev_dbg(i2c->dev, "Deal with arbitration lose\n");
i2c->state = -EAGAIN;
goto stop;
} else if (int_status & HSI2C_INT_NO_DEV_ACK) {
dev_dbg(i2c->dev, "No ACK from device\n");
i2c->state = -ENXIO;
goto stop;
} else if (int_status & HSI2C_INT_NO_DEV) {
dev_dbg(i2c->dev, "No device\n");
i2c->state = -ENXIO;
goto stop;
} else if (int_status & HSI2C_INT_TIMEOUT) {
dev_dbg(i2c->dev, "Accessing device timed out\n");
i2c->state = -ETIMEDOUT;
goto stop;
}
} else if (int_status & HSI2C_INT_I2C) {
trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
if (trans_status & HSI2C_NO_DEV_ACK) {
dev_dbg(i2c->dev, "No ACK from device\n");
i2c->state = -ENXIO;
goto stop;
} else if (trans_status & HSI2C_NO_DEV) {
dev_dbg(i2c->dev, "No device\n");
i2c->state = -ENXIO;
goto stop;
} else if (trans_status & HSI2C_TRANS_ABORT) {
dev_dbg(i2c->dev, "Deal with arbitration lose\n");
i2c->state = -EAGAIN;
goto stop;
} else if (trans_status & HSI2C_TIMEOUT_AUTO) {
dev_dbg(i2c->dev, "Accessing device timed out\n");
i2c->state = -ETIMEDOUT;
goto stop;
} else if (trans_status & HSI2C_TRANS_DONE) {
i2c->trans_done = 1;
i2c->state = 0;
}
}
if ((i2c->msg->flags & I2C_M_RD) && (int_status &
(HSI2C_INT_TRAILING | HSI2C_INT_RX_ALMOSTFULL))) {
fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
fifo_level = HSI2C_RX_FIFO_LVL(fifo_status);
len = min(fifo_level, i2c->msg->len - i2c->msg_ptr);
while (len > 0) {
byte = (unsigned char)
readl(i2c->regs + HSI2C_RX_DATA);
i2c->msg->buf[i2c->msg_ptr++] = byte;
len--;
}
i2c->state = 0;
} else if (int_status & HSI2C_INT_TX_ALMOSTEMPTY) {
fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
fifo_level = HSI2C_TX_FIFO_LVL(fifo_status);
len = i2c->variant->fifo_depth - fifo_level;
if (len > (i2c->msg->len - i2c->msg_ptr)) {
u32 int_en = readl(i2c->regs + HSI2C_INT_ENABLE);
int_en &= ~HSI2C_INT_TX_ALMOSTEMPTY_EN;
writel(int_en, i2c->regs + HSI2C_INT_ENABLE);
len = i2c->msg->len - i2c->msg_ptr;
}
while (len > 0) {
byte = i2c->msg->buf[i2c->msg_ptr++];
writel(byte, i2c->regs + HSI2C_TX_DATA);
len--;
}
i2c->state = 0;
}
stop:
if ((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) ||
(i2c->state < 0)) {
writel(0, i2c->regs + HSI2C_INT_ENABLE);
exynos5_i2c_clr_pend_irq(i2c);
complete(&i2c->msg_complete);
}
spin_unlock(&i2c->lock);
return IRQ_HANDLED;
}
/*
* exynos5_i2c_wait_bus_idle
*
* Wait for the bus to go idle, indicated by the MASTER_BUSY bit being
* cleared.
*
* Returns -EBUSY if the bus cannot be bought to idle
*/
static int exynos5_i2c_wait_bus_idle(struct exynos5_i2c *i2c)
{
unsigned long stop_time;
u32 trans_status;
/* wait for 100 milli seconds for the bus to be idle */
stop_time = jiffies + msecs_to_jiffies(100) + 1;
do {
trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
if (!(trans_status & HSI2C_MASTER_BUSY))
return 0;
usleep_range(50, 200);
} while (time_before(jiffies, stop_time));
return -EBUSY;
}
static void exynos5_i2c_bus_recover(struct exynos5_i2c *i2c)
{
u32 val;
val = readl(i2c->regs + HSI2C_CTL) | HSI2C_RXCHON;
writel(val, i2c->regs + HSI2C_CTL);
val = readl(i2c->regs + HSI2C_CONF) & ~HSI2C_AUTO_MODE;
writel(val, i2c->regs + HSI2C_CONF);
/*
* Specification says master should send nine clock pulses. It can be
* emulated by sending manual read command (nine pulses for read eight
* bits + one pulse for NACK).
*/
writel(HSI2C_CMD_READ_DATA, i2c->regs + HSI2C_MANUAL_CMD);
exynos5_i2c_wait_bus_idle(i2c);
writel(HSI2C_CMD_SEND_STOP, i2c->regs + HSI2C_MANUAL_CMD);
exynos5_i2c_wait_bus_idle(i2c);
val = readl(i2c->regs + HSI2C_CTL) & ~HSI2C_RXCHON;
writel(val, i2c->regs + HSI2C_CTL);
val = readl(i2c->regs + HSI2C_CONF) | HSI2C_AUTO_MODE;
writel(val, i2c->regs + HSI2C_CONF);
}
static void exynos5_i2c_bus_check(struct exynos5_i2c *i2c)
{
unsigned long timeout;
if (i2c->variant->hw != HSI2C_EXYNOS7)
return;
/*
* HSI2C_MASTER_ST_LOSE state in EXYNOS7 variant before transaction
* indicates that bus is stuck (SDA is low). In such case bus recovery
* can be performed.
*/
timeout = jiffies + msecs_to_jiffies(100);
for (;;) {
u32 st = readl(i2c->regs + HSI2C_TRANS_STATUS);
if ((st & HSI2C_MASTER_ST_MASK) != HSI2C_MASTER_ST_LOSE)
return;
if (time_is_before_jiffies(timeout))
return;
exynos5_i2c_bus_recover(i2c);
}
}
/*
* exynos5_i2c_message_start: Configures the bus and starts the xfer
* i2c: struct exynos5_i2c pointer for the current bus
* stop: Enables stop after transfer if set. Set for last transfer of
* in the list of messages.
*
* Configures the bus for read/write function
* Sets chip address to talk to, message length to be sent.
* Enables appropriate interrupts and sends start xfer command.
*/
static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
{
u32 i2c_ctl;
u32 int_en = 0;
u32 i2c_auto_conf = 0;
u32 fifo_ctl;
unsigned long flags;
unsigned short trig_lvl;
if (i2c->variant->hw == HSI2C_EXYNOS7)
int_en |= HSI2C_INT_I2C_TRANS;
else
int_en |= HSI2C_INT_I2C;
i2c_ctl = readl(i2c->regs + HSI2C_CTL);
i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN;
if (i2c->msg->flags & I2C_M_RD) {
i2c_ctl |= HSI2C_RXCHON;
i2c_auto_conf |= HSI2C_READ_WRITE;
trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ?
(i2c->variant->fifo_depth * 3 / 4) : i2c->msg->len;
fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(trig_lvl);
int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN |
HSI2C_INT_TRAILING_EN);
} else {
i2c_ctl |= HSI2C_TXCHON;
trig_lvl = (i2c->msg->len > i2c->variant->fifo_depth) ?
(i2c->variant->fifo_depth * 1 / 4) : i2c->msg->len;
fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(trig_lvl);
int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN;
}
writel(HSI2C_SLV_ADDR_MAS(i2c->msg->addr), i2c->regs + HSI2C_ADDR);
writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL);
writel(i2c_ctl, i2c->regs + HSI2C_CTL);
exynos5_i2c_bus_check(i2c);
/*
* Enable interrupts before starting the transfer so that we don't
* miss any INT_I2C interrupts.
*/
spin_lock_irqsave(&i2c->lock, flags);
writel(int_en, i2c->regs + HSI2C_INT_ENABLE);
if (stop == 1)
i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS;
i2c_auto_conf |= i2c->msg->len;
i2c_auto_conf |= HSI2C_MASTER_RUN;
writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF);
spin_unlock_irqrestore(&i2c->lock, flags);
}
static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c,
struct i2c_msg *msgs, int stop)
{
unsigned long timeout;
int ret;
i2c->msg = msgs;
i2c->msg_ptr = 0;
i2c->trans_done = 0;
reinit_completion(&i2c->msg_complete);
exynos5_i2c_message_start(i2c, stop);
timeout = wait_for_completion_timeout(&i2c->msg_complete,
EXYNOS5_I2C_TIMEOUT);
if (timeout == 0)
ret = -ETIMEDOUT;
else
ret = i2c->state;
/*
* If this is the last message to be transfered (stop == 1)
* Then check if the bus can be brought back to idle.
*/
if (ret == 0 && stop)
ret = exynos5_i2c_wait_bus_idle(i2c);
if (ret < 0) {
exynos5_i2c_reset(i2c);
if (ret == -ETIMEDOUT)
dev_warn(i2c->dev, "%s timeout\n",
(msgs->flags & I2C_M_RD) ? "rx" : "tx");
}
/* Return the state as in interrupt routine */
return ret;
}
static int exynos5_i2c_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct exynos5_i2c *i2c = adap->algo_data;
int i = 0, ret = 0, stop = 0;
if (i2c->suspended) {
dev_err(i2c->dev, "HS-I2C is not initialized.\n");
return -EIO;
}
ret = clk_enable(i2c->clk);
if (ret)
return ret;
for (i = 0; i < num; i++, msgs++) {
stop = (i == num - 1);
ret = exynos5_i2c_xfer_msg(i2c, msgs, stop);
if (ret < 0)
goto out;
}
if (i == num) {
ret = num;
} else {
/* Only one message, cannot access the device */
if (i == 1)
ret = -EREMOTEIO;
else
ret = i;
dev_warn(i2c->dev, "xfer message failed\n");
}
out:
clk_disable(i2c->clk);
return ret;
}
static u32 exynos5_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}
static const struct i2c_algorithm exynos5_i2c_algorithm = {
.master_xfer = exynos5_i2c_xfer,
.functionality = exynos5_i2c_func,
};
static int exynos5_i2c_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct exynos5_i2c *i2c;
struct resource *mem;
int ret;
i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
if (of_property_read_u32(np, "clock-frequency", &i2c->op_clock))
i2c->op_clock = HSI2C_FS_TX_CLOCK;
strlcpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name));
i2c->adap.owner = THIS_MODULE;
i2c->adap.algo = &exynos5_i2c_algorithm;
i2c->adap.retries = 3;
i2c->dev = &pdev->dev;
i2c->clk = devm_clk_get(&pdev->dev, "hsi2c");
if (IS_ERR(i2c->clk)) {
dev_err(&pdev->dev, "cannot get clock\n");
return -ENOENT;
}
ret = clk_prepare_enable(i2c->clk);
if (ret)
return ret;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(i2c->regs)) {
ret = PTR_ERR(i2c->regs);
goto err_clk;
}
i2c->adap.dev.of_node = np;
i2c->adap.algo_data = i2c;
i2c->adap.dev.parent = &pdev->dev;
/* Clear pending interrupts from u-boot or misc causes */
exynos5_i2c_clr_pend_irq(i2c);
spin_lock_init(&i2c->lock);
init_completion(&i2c->msg_complete);
i2c->irq = ret = platform_get_irq(pdev, 0);
if (ret <= 0) {
dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
ret = -EINVAL;
goto err_clk;
}
ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq,
IRQF_NO_SUSPEND | IRQF_ONESHOT,
dev_name(&pdev->dev), i2c);
if (ret != 0) {
dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq);
goto err_clk;
}
i2c->variant = of_device_get_match_data(&pdev->dev);
ret = exynos5_hsi2c_clock_setup(i2c);
if (ret)
goto err_clk;
exynos5_i2c_reset(i2c);
ret = i2c_add_adapter(&i2c->adap);
if (ret < 0)
goto err_clk;
platform_set_drvdata(pdev, i2c);
clk_disable(i2c->clk);
return 0;
err_clk:
clk_disable_unprepare(i2c->clk);
return ret;
}
static int exynos5_i2c_remove(struct platform_device *pdev)
{
struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c->adap);
clk_unprepare(i2c->clk);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int exynos5_i2c_suspend_noirq(struct device *dev)
{
struct exynos5_i2c *i2c = dev_get_drvdata(dev);
i2c->suspended = 1;
clk_unprepare(i2c->clk);
return 0;
}
static int exynos5_i2c_resume_noirq(struct device *dev)
{
struct exynos5_i2c *i2c = dev_get_drvdata(dev);
int ret = 0;
ret = clk_prepare_enable(i2c->clk);
if (ret)
return ret;
ret = exynos5_hsi2c_clock_setup(i2c);
if (ret) {
clk_disable_unprepare(i2c->clk);
return ret;
}
exynos5_i2c_init(i2c);
clk_disable(i2c->clk);
i2c->suspended = 0;
return 0;
}
#endif
static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = {
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(exynos5_i2c_suspend_noirq,
exynos5_i2c_resume_noirq)
};
static struct platform_driver exynos5_i2c_driver = {
.probe = exynos5_i2c_probe,
.remove = exynos5_i2c_remove,
.driver = {
.name = "exynos5-hsi2c",
.pm = &exynos5_i2c_dev_pm_ops,
.of_match_table = exynos5_i2c_match,
},
};
module_platform_driver(exynos5_i2c_driver);
MODULE_DESCRIPTION("Exynos5 HS-I2C Bus driver");
MODULE_AUTHOR("Naveen Krishna Chatradhi, <ch.naveen@samsung.com>");
MODULE_AUTHOR("Taekgyun Ko, <taeggyun.ko@samsung.com>");
MODULE_LICENSE("GPL v2");
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