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WSL2-Linux-Kernel/drivers/i2c/busses/i2c-st.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2013 STMicroelectronics
*
* I2C master mode controller driver, used in STMicroelectronics devices.
*
* Author: Maxime Coquelin <maxime.coquelin@st.com>
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
/* SSC registers */
#define SSC_BRG 0x000
#define SSC_TBUF 0x004
#define SSC_RBUF 0x008
#define SSC_CTL 0x00C
#define SSC_IEN 0x010
#define SSC_STA 0x014
#define SSC_I2C 0x018
#define SSC_SLAD 0x01C
#define SSC_REP_START_HOLD 0x020
#define SSC_START_HOLD 0x024
#define SSC_REP_START_SETUP 0x028
#define SSC_DATA_SETUP 0x02C
#define SSC_STOP_SETUP 0x030
#define SSC_BUS_FREE 0x034
#define SSC_TX_FSTAT 0x038
#define SSC_RX_FSTAT 0x03C
#define SSC_PRE_SCALER_BRG 0x040
#define SSC_CLR 0x080
#define SSC_NOISE_SUPP_WIDTH 0x100
#define SSC_PRSCALER 0x104
#define SSC_NOISE_SUPP_WIDTH_DATAOUT 0x108
#define SSC_PRSCALER_DATAOUT 0x10c
/* SSC Control */
#define SSC_CTL_DATA_WIDTH_9 0x8
#define SSC_CTL_DATA_WIDTH_MSK 0xf
#define SSC_CTL_BM 0xf
#define SSC_CTL_HB BIT(4)
#define SSC_CTL_PH BIT(5)
#define SSC_CTL_PO BIT(6)
#define SSC_CTL_SR BIT(7)
#define SSC_CTL_MS BIT(8)
#define SSC_CTL_EN BIT(9)
#define SSC_CTL_LPB BIT(10)
#define SSC_CTL_EN_TX_FIFO BIT(11)
#define SSC_CTL_EN_RX_FIFO BIT(12)
#define SSC_CTL_EN_CLST_RX BIT(13)
/* SSC Interrupt Enable */
#define SSC_IEN_RIEN BIT(0)
#define SSC_IEN_TIEN BIT(1)
#define SSC_IEN_TEEN BIT(2)
#define SSC_IEN_REEN BIT(3)
#define SSC_IEN_PEEN BIT(4)
#define SSC_IEN_AASEN BIT(6)
#define SSC_IEN_STOPEN BIT(7)
#define SSC_IEN_ARBLEN BIT(8)
#define SSC_IEN_NACKEN BIT(10)
#define SSC_IEN_REPSTRTEN BIT(11)
#define SSC_IEN_TX_FIFO_HALF BIT(12)
#define SSC_IEN_RX_FIFO_HALF_FULL BIT(14)
/* SSC Status */
#define SSC_STA_RIR BIT(0)
#define SSC_STA_TIR BIT(1)
#define SSC_STA_TE BIT(2)
#define SSC_STA_RE BIT(3)
#define SSC_STA_PE BIT(4)
#define SSC_STA_CLST BIT(5)
#define SSC_STA_AAS BIT(6)
#define SSC_STA_STOP BIT(7)
#define SSC_STA_ARBL BIT(8)
#define SSC_STA_BUSY BIT(9)
#define SSC_STA_NACK BIT(10)
#define SSC_STA_REPSTRT BIT(11)
#define SSC_STA_TX_FIFO_HALF BIT(12)
#define SSC_STA_TX_FIFO_FULL BIT(13)
#define SSC_STA_RX_FIFO_HALF BIT(14)
/* SSC I2C Control */
#define SSC_I2C_I2CM BIT(0)
#define SSC_I2C_STRTG BIT(1)
#define SSC_I2C_STOPG BIT(2)
#define SSC_I2C_ACKG BIT(3)
#define SSC_I2C_AD10 BIT(4)
#define SSC_I2C_TXENB BIT(5)
#define SSC_I2C_REPSTRTG BIT(11)
#define SSC_I2C_SLAVE_DISABLE BIT(12)
/* SSC Tx FIFO Status */
#define SSC_TX_FSTAT_STATUS 0x07
/* SSC Rx FIFO Status */
#define SSC_RX_FSTAT_STATUS 0x07
/* SSC Clear bit operation */
#define SSC_CLR_SSCAAS BIT(6)
#define SSC_CLR_SSCSTOP BIT(7)
#define SSC_CLR_SSCARBL BIT(8)
#define SSC_CLR_NACK BIT(10)
#define SSC_CLR_REPSTRT BIT(11)
/* SSC Clock Prescaler */
#define SSC_PRSC_VALUE 0x0f
#define SSC_TXFIFO_SIZE 0x8
#define SSC_RXFIFO_SIZE 0x8
enum st_i2c_mode {
I2C_MODE_STANDARD,
I2C_MODE_FAST,
I2C_MODE_END,
};
/**
* struct st_i2c_timings - per-Mode tuning parameters
* @rate: I2C bus rate
* @rep_start_hold: I2C repeated start hold time requirement
* @rep_start_setup: I2C repeated start set up time requirement
* @start_hold: I2C start hold time requirement
* @data_setup_time: I2C data set up time requirement
* @stop_setup_time: I2C stop set up time requirement
* @bus_free_time: I2C bus free time requirement
* @sda_pulse_min_limit: I2C SDA pulse mini width limit
*/
struct st_i2c_timings {
u32 rate;
u32 rep_start_hold;
u32 rep_start_setup;
u32 start_hold;
u32 data_setup_time;
u32 stop_setup_time;
u32 bus_free_time;
u32 sda_pulse_min_limit;
};
/**
* struct st_i2c_client - client specific data
* @addr: 8-bit slave addr, including r/w bit
* @count: number of bytes to be transfered
* @xfered: number of bytes already transferred
* @buf: data buffer
* @result: result of the transfer
* @stop: last I2C msg to be sent, i.e. STOP to be generated
*/
struct st_i2c_client {
u8 addr;
u32 count;
u32 xfered;
u8 *buf;
int result;
bool stop;
};
/**
* struct st_i2c_dev - private data of the controller
* @adap: I2C adapter for this controller
* @dev: device for this controller
* @base: virtual memory area
* @complete: completion of I2C message
* @irq: interrupt line for th controller
* @clk: hw ssc block clock
* @mode: I2C mode of the controller. Standard or Fast only supported
* @scl_min_width_us: SCL line minimum pulse width in us
* @sda_min_width_us: SDA line minimum pulse width in us
* @client: I2C transfert information
* @busy: I2C transfer on-going
*/
struct st_i2c_dev {
struct i2c_adapter adap;
struct device *dev;
void __iomem *base;
struct completion complete;
int irq;
struct clk *clk;
int mode;
u32 scl_min_width_us;
u32 sda_min_width_us;
struct st_i2c_client client;
bool busy;
};
static inline void st_i2c_set_bits(void __iomem *reg, u32 mask)
{
writel_relaxed(readl_relaxed(reg) | mask, reg);
}
static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask)
{
writel_relaxed(readl_relaxed(reg) & ~mask, reg);
}
/*
* From I2C Specifications v0.5.
*
* All the values below have +10% margin added to be
* compatible with some out-of-spec devices,
* like HDMI link of the Toshiba 19AV600 TV.
*/
static struct st_i2c_timings i2c_timings[] = {
[I2C_MODE_STANDARD] = {
.rate = I2C_MAX_STANDARD_MODE_FREQ,
.rep_start_hold = 4400,
.rep_start_setup = 5170,
.start_hold = 4400,
.data_setup_time = 275,
.stop_setup_time = 4400,
.bus_free_time = 5170,
},
[I2C_MODE_FAST] = {
.rate = I2C_MAX_FAST_MODE_FREQ,
.rep_start_hold = 660,
.rep_start_setup = 660,
.start_hold = 660,
.data_setup_time = 110,
.stop_setup_time = 660,
.bus_free_time = 1430,
},
};
static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev)
{
int count, i;
/*
* Counter only counts up to 7 but fifo size is 8...
* When fifo is full, counter is 0 and RIR bit of status register is
* set
*/
if (readl_relaxed(i2c_dev->base + SSC_STA) & SSC_STA_RIR)
count = SSC_RXFIFO_SIZE;
else
count = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT) &
SSC_RX_FSTAT_STATUS;
for (i = 0; i < count; i++)
readl_relaxed(i2c_dev->base + SSC_RBUF);
}
static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev)
{
/*
* FIFO needs to be emptied before reseting the IP,
* else the controller raises a BUSY error.
*/
st_i2c_flush_rx_fifo(i2c_dev);
st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR);
st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR);
}
/**
* st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings
* @i2c_dev: Controller's private data
*/
static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev)
{
unsigned long rate;
u32 val, ns_per_clk;
struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode];
st_i2c_soft_reset(i2c_dev);
val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL |
SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP;
writel_relaxed(val, i2c_dev->base + SSC_CLR);
/* SSC Control register setup */
val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9;
writel_relaxed(val, i2c_dev->base + SSC_CTL);
rate = clk_get_rate(i2c_dev->clk);
ns_per_clk = 1000000000 / rate;
/* Baudrate */
val = rate / (2 * t->rate);
writel_relaxed(val, i2c_dev->base + SSC_BRG);
/* Pre-scaler baudrate */
writel_relaxed(1, i2c_dev->base + SSC_PRE_SCALER_BRG);
/* Enable I2C mode */
writel_relaxed(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C);
/* Repeated start hold time */
val = t->rep_start_hold / ns_per_clk;
writel_relaxed(val, i2c_dev->base + SSC_REP_START_HOLD);
/* Repeated start set up time */
val = t->rep_start_setup / ns_per_clk;
writel_relaxed(val, i2c_dev->base + SSC_REP_START_SETUP);
/* Start hold time */
val = t->start_hold / ns_per_clk;
writel_relaxed(val, i2c_dev->base + SSC_START_HOLD);
/* Data set up time */
val = t->data_setup_time / ns_per_clk;
writel_relaxed(val, i2c_dev->base + SSC_DATA_SETUP);
/* Stop set up time */
val = t->stop_setup_time / ns_per_clk;
writel_relaxed(val, i2c_dev->base + SSC_STOP_SETUP);
/* Bus free time */
val = t->bus_free_time / ns_per_clk;
writel_relaxed(val, i2c_dev->base + SSC_BUS_FREE);
/* Prescalers set up */
val = rate / 10000000;
writel_relaxed(val, i2c_dev->base + SSC_PRSCALER);
writel_relaxed(val, i2c_dev->base + SSC_PRSCALER_DATAOUT);
/* Noise suppression witdh */
val = i2c_dev->scl_min_width_us * rate / 100000000;
writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH);
/* Noise suppression max output data delay width */
val = i2c_dev->sda_min_width_us * rate / 100000000;
writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT);
}
static int st_i2c_recover_bus(struct i2c_adapter *i2c_adap)
{
struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
u32 ctl;
dev_dbg(i2c_dev->dev, "Trying to recover bus\n");
/*
* SSP IP is dual role SPI/I2C to generate 9 clock pulses
* we switch to SPI node, 9 bit words and write a 0. This
* has been validate with a oscilloscope and is easier
* than switching to GPIO mode.
*/
/* Disable interrupts */
writel_relaxed(0, i2c_dev->base + SSC_IEN);
st_i2c_hw_config(i2c_dev);
ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO;
st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);
st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
usleep_range(8000, 10000);
writel_relaxed(0, i2c_dev->base + SSC_TBUF);
usleep_range(2000, 4000);
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_I2CM);
return 0;
}
static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
{
u32 sta;
int i, ret;
for (i = 0; i < 10; i++) {
sta = readl_relaxed(i2c_dev->base + SSC_STA);
if (!(sta & SSC_STA_BUSY))
return 0;
usleep_range(2000, 4000);
}
dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta);
ret = i2c_recover_bus(&i2c_dev->adap);
if (ret) {
dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret);
return ret;
}
return -EBUSY;
}
/**
* st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO
* @i2c_dev: Controller's private data
* @byte: Data to write in the Tx FIFO
*/
static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte)
{
u16 tbuf = byte << 1;
writel_relaxed(tbuf | 1, i2c_dev->base + SSC_TBUF);
}
/**
* st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode
* @i2c_dev: Controller's private data
*
* This functions fills the Tx FIFO with I2C transfert buffer when
* in write mode.
*/
static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev)
{
struct st_i2c_client *c = &i2c_dev->client;
u32 tx_fstat, sta;
int i;
sta = readl_relaxed(i2c_dev->base + SSC_STA);
if (sta & SSC_STA_TX_FIFO_FULL)
return;
tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT);
tx_fstat &= SSC_TX_FSTAT_STATUS;
if (c->count < (SSC_TXFIFO_SIZE - tx_fstat))
i = c->count;
else
i = SSC_TXFIFO_SIZE - tx_fstat;
for (; i > 0; i--, c->count--, c->buf++)
st_i2c_write_tx_fifo(i2c_dev, *c->buf);
}
/**
* st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode
* @i2c_dev: Controller's private data
* @max: Maximum amount of data to fill into the Tx FIFO
*
* This functions fills the Tx FIFO with fixed pattern when
* in read mode to trigger clock.
*/
static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max)
{
struct st_i2c_client *c = &i2c_dev->client;
u32 tx_fstat, sta;
int i;
sta = readl_relaxed(i2c_dev->base + SSC_STA);
if (sta & SSC_STA_TX_FIFO_FULL)
return;
tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT);
tx_fstat &= SSC_TX_FSTAT_STATUS;
if (max < (SSC_TXFIFO_SIZE - tx_fstat))
i = max;
else
i = SSC_TXFIFO_SIZE - tx_fstat;
for (; i > 0; i--, c->xfered++)
st_i2c_write_tx_fifo(i2c_dev, 0xff);
}
static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev)
{
struct st_i2c_client *c = &i2c_dev->client;
u32 i, sta;
u16 rbuf;
sta = readl_relaxed(i2c_dev->base + SSC_STA);
if (sta & SSC_STA_RIR) {
i = SSC_RXFIFO_SIZE;
} else {
i = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT);
i &= SSC_RX_FSTAT_STATUS;
}
for (; (i > 0) && (c->count > 0); i--, c->count--) {
rbuf = readl_relaxed(i2c_dev->base + SSC_RBUF) >> 1;
*c->buf++ = (u8)rbuf & 0xff;
}
if (i) {
dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i);
st_i2c_flush_rx_fifo(i2c_dev);
}
}
/**
* st_i2c_terminate_xfer() - Send either STOP or REPSTART condition
* @i2c_dev: Controller's private data
*/
static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev)
{
struct st_i2c_client *c = &i2c_dev->client;
st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN);
st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG);
if (c->stop) {
st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN);
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
} else {
st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN);
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG);
}
}
/**
* st_i2c_handle_write() - Handle FIFO empty interrupt in case of write
* @i2c_dev: Controller's private data
*/
static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev)
{
struct st_i2c_client *c = &i2c_dev->client;
st_i2c_flush_rx_fifo(i2c_dev);
if (!c->count)
/* End of xfer, send stop or repstart */
st_i2c_terminate_xfer(i2c_dev);
else
st_i2c_wr_fill_tx_fifo(i2c_dev);
}
/**
* st_i2c_handle_write() - Handle FIFO enmpty interrupt in case of read
* @i2c_dev: Controller's private data
*/
static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev)
{
struct st_i2c_client *c = &i2c_dev->client;
u32 ien;
/* Trash the address read back */
if (!c->xfered) {
readl_relaxed(i2c_dev->base + SSC_RBUF);
st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB);
} else {
st_i2c_read_rx_fifo(i2c_dev);
}
if (!c->count) {
/* End of xfer, send stop or repstart */
st_i2c_terminate_xfer(i2c_dev);
} else if (c->count == 1) {
/* Penultimate byte to xfer, disable ACK gen. */
st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG);
/* Last received byte is to be handled by NACK interrupt */
ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN;
writel_relaxed(ien, i2c_dev->base + SSC_IEN);
st_i2c_rd_fill_tx_fifo(i2c_dev, c->count);
} else {
st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1);
}
}
/**
* st_i2c_isr() - Interrupt routine
* @irq: interrupt number
* @data: Controller's private data
*/
static irqreturn_t st_i2c_isr_thread(int irq, void *data)
{
struct st_i2c_dev *i2c_dev = data;
struct st_i2c_client *c = &i2c_dev->client;
u32 sta, ien;
int it;
ien = readl_relaxed(i2c_dev->base + SSC_IEN);
sta = readl_relaxed(i2c_dev->base + SSC_STA);
/* Use __fls() to check error bits first */
it = __fls(sta & ien);
if (it < 0) {
dev_dbg(i2c_dev->dev, "spurious it (sta=0x%04x, ien=0x%04x)\n",
sta, ien);
return IRQ_NONE;
}
switch (1 << it) {
case SSC_STA_TE:
if (c->addr & I2C_M_RD)
st_i2c_handle_read(i2c_dev);
else
st_i2c_handle_write(i2c_dev);
break;
case SSC_STA_STOP:
case SSC_STA_REPSTRT:
writel_relaxed(0, i2c_dev->base + SSC_IEN);
complete(&i2c_dev->complete);
break;
case SSC_STA_NACK:
writel_relaxed(SSC_CLR_NACK, i2c_dev->base + SSC_CLR);
/* Last received byte handled by NACK interrupt */
if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) {
st_i2c_handle_read(i2c_dev);
break;
}
it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN;
writel_relaxed(it, i2c_dev->base + SSC_IEN);
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
c->result = -EIO;
break;
case SSC_STA_ARBL:
writel_relaxed(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR);
it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN;
writel_relaxed(it, i2c_dev->base + SSC_IEN);
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
c->result = -EAGAIN;
break;
default:
dev_err(i2c_dev->dev,
"it %d unhandled (sta=0x%04x)\n", it, sta);
}
/*
* Read IEN register to ensure interrupt mask write is effective
* before re-enabling interrupt at GIC level, and thus avoid spurious
* interrupts.
*/
readl(i2c_dev->base + SSC_IEN);
return IRQ_HANDLED;
}
/**
* st_i2c_xfer_msg() - Transfer a single I2C message
* @i2c_dev: Controller's private data
* @msg: I2C message to transfer
* @is_first: first message of the sequence
* @is_last: last message of the sequence
*/
static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg,
bool is_first, bool is_last)
{
struct st_i2c_client *c = &i2c_dev->client;
u32 ctl, i2c, it;
unsigned long timeout;
int ret;
c->addr = i2c_8bit_addr_from_msg(msg);
c->buf = msg->buf;
c->count = msg->len;
c->xfered = 0;
c->result = 0;
c->stop = is_last;
reinit_completion(&i2c_dev->complete);
ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO;
st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);
i2c = SSC_I2C_TXENB;
if (c->addr & I2C_M_RD)
i2c |= SSC_I2C_ACKG;
st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c);
/* Write slave address */
st_i2c_write_tx_fifo(i2c_dev, c->addr);
/* Pre-fill Tx fifo with data in case of write */
if (!(c->addr & I2C_M_RD))
st_i2c_wr_fill_tx_fifo(i2c_dev);
it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN;
writel_relaxed(it, i2c_dev->base + SSC_IEN);
if (is_first) {
ret = st_i2c_wait_free_bus(i2c_dev);
if (ret)
return ret;
st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG);
}
timeout = wait_for_completion_timeout(&i2c_dev->complete,
i2c_dev->adap.timeout);
ret = c->result;
if (!timeout) {
dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n",
c->addr);
ret = -ETIMEDOUT;
}
i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG;
st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c);
writel_relaxed(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT,
i2c_dev->base + SSC_CLR);
return ret;
}
/**
* st_i2c_xfer() - Transfer a single I2C message
* @i2c_adap: Adapter pointer to the controller
* @msgs: Pointer to data to be written.
* @num: Number of messages to be executed
*/
static int st_i2c_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg msgs[], int num)
{
struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
int ret, i;
i2c_dev->busy = true;
ret = clk_prepare_enable(i2c_dev->clk);
if (ret) {
dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n");
return ret;
}
pinctrl_pm_select_default_state(i2c_dev->dev);
st_i2c_hw_config(i2c_dev);
for (i = 0; (i < num) && !ret; i++)
ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1);
pinctrl_pm_select_idle_state(i2c_dev->dev);
clk_disable_unprepare(i2c_dev->clk);
i2c_dev->busy = false;
return (ret < 0) ? ret : i;
}
#ifdef CONFIG_PM_SLEEP
static int st_i2c_suspend(struct device *dev)
{
struct st_i2c_dev *i2c_dev = dev_get_drvdata(dev);
if (i2c_dev->busy)
return -EBUSY;
pinctrl_pm_select_sleep_state(dev);
return 0;
}
static int st_i2c_resume(struct device *dev)
{
pinctrl_pm_select_default_state(dev);
/* Go in idle state if available */
pinctrl_pm_select_idle_state(dev);
return 0;
}
static SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume);
#define ST_I2C_PM (&st_i2c_pm)
#else
#define ST_I2C_PM NULL
#endif
static u32 st_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm st_i2c_algo = {
.master_xfer = st_i2c_xfer,
.functionality = st_i2c_func,
};
static struct i2c_bus_recovery_info st_i2c_recovery_info = {
.recover_bus = st_i2c_recover_bus,
};
static int st_i2c_of_get_deglitch(struct device_node *np,
struct st_i2c_dev *i2c_dev)
{
int ret;
ret = of_property_read_u32(np, "st,i2c-min-scl-pulse-width-us",
&i2c_dev->scl_min_width_us);
if ((ret == -ENODATA) || (ret == -EOVERFLOW)) {
dev_err(i2c_dev->dev, "st,i2c-min-scl-pulse-width-us invalid\n");
return ret;
}
ret = of_property_read_u32(np, "st,i2c-min-sda-pulse-width-us",
&i2c_dev->sda_min_width_us);
if ((ret == -ENODATA) || (ret == -EOVERFLOW)) {
dev_err(i2c_dev->dev, "st,i2c-min-sda-pulse-width-us invalid\n");
return ret;
}
return 0;
}
static int st_i2c_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct st_i2c_dev *i2c_dev;
struct resource *res;
u32 clk_rate;
struct i2c_adapter *adap;
int ret;
i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
if (!i2c_dev)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
i2c_dev->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(i2c_dev->base))
return PTR_ERR(i2c_dev->base);
i2c_dev->irq = irq_of_parse_and_map(np, 0);
if (!i2c_dev->irq) {
dev_err(&pdev->dev, "IRQ missing or invalid\n");
return -EINVAL;
}
i2c_dev->clk = of_clk_get_by_name(np, "ssc");
if (IS_ERR(i2c_dev->clk)) {
dev_err(&pdev->dev, "Unable to request clock\n");
return PTR_ERR(i2c_dev->clk);
}
i2c_dev->mode = I2C_MODE_STANDARD;
ret = of_property_read_u32(np, "clock-frequency", &clk_rate);
if (!ret && (clk_rate == I2C_MAX_FAST_MODE_FREQ))
i2c_dev->mode = I2C_MODE_FAST;
i2c_dev->dev = &pdev->dev;
ret = devm_request_threaded_irq(&pdev->dev, i2c_dev->irq,
NULL, st_i2c_isr_thread,
IRQF_ONESHOT, pdev->name, i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
return ret;
}
pinctrl_pm_select_default_state(i2c_dev->dev);
/* In case idle state available, select it */
pinctrl_pm_select_idle_state(i2c_dev->dev);
ret = st_i2c_of_get_deglitch(np, i2c_dev);
if (ret)
return ret;
adap = &i2c_dev->adap;
i2c_set_adapdata(adap, i2c_dev);
snprintf(adap->name, sizeof(adap->name), "ST I2C(%pa)", &res->start);
adap->owner = THIS_MODULE;
adap->timeout = 2 * HZ;
adap->retries = 0;
adap->algo = &st_i2c_algo;
adap->bus_recovery_info = &st_i2c_recovery_info;
adap->dev.parent = &pdev->dev;
adap->dev.of_node = pdev->dev.of_node;
init_completion(&i2c_dev->complete);
ret = i2c_add_adapter(adap);
if (ret)
return ret;
platform_set_drvdata(pdev, i2c_dev);
dev_info(i2c_dev->dev, "%s initialized\n", adap->name);
return 0;
}
static int st_i2c_remove(struct platform_device *pdev)
{
struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
i2c_del_adapter(&i2c_dev->adap);
return 0;
}
static const struct of_device_id st_i2c_match[] = {
{ .compatible = "st,comms-ssc-i2c", },
{ .compatible = "st,comms-ssc4-i2c", },
{},
};
MODULE_DEVICE_TABLE(of, st_i2c_match);
static struct platform_driver st_i2c_driver = {
.driver = {
.name = "st-i2c",
.of_match_table = st_i2c_match,
.pm = ST_I2C_PM,
},
.probe = st_i2c_probe,
.remove = st_i2c_remove,
};
module_platform_driver(st_i2c_driver);
MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>");
MODULE_DESCRIPTION("STMicroelectronics I2C driver");
MODULE_LICENSE("GPL v2");
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