Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 914 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-st.c b/drivers/i2c/busses/i2c-st.c
new file mode 100644
index 000000000..faa81a955
--- /dev/null
+++ b/drivers/i2c/busses/i2c-st.c
@@ -0,0 +1,914 @@
+// 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");