[PATCH v2 13/14] i2c: Add support for Qualcomm I2C driver

Sumit Garg sumit.garg at linaro.org
Wed Feb 1 14:59:00 CET 2023


Add support for Qualcomm I2C QUP driver which is inspired from
corresponding driver in Linux: drivers/i2c/busses/i2c-qup.c.

Currently this driver only support FIFO polling mode which is sufficient
to support devices like eeprom, rtc etc.

Co-developed-by: Mike Worsfold <mworsfold at impinj.com>
Signed-off-by: Mike Worsfold <mworsfold at impinj.com>
Signed-off-by: Sumit Garg <sumit.garg at linaro.org>
---
 drivers/i2c/Kconfig   |  12 +
 drivers/i2c/Makefile  |   1 +
 drivers/i2c/qup_i2c.c | 579 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 592 insertions(+)
 create mode 100644 drivers/i2c/qup_i2c.c

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 76e19918aa..427074bff8 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -580,6 +580,18 @@ config SYS_I2C_OCTEON
 	  chips have several I2C ports and all are provided, controlled by
 	  the device tree.
 
+config SYS_I2C_QUP
+	bool "Qualcomm QUP I2C controller"
+	depends on ARCH_SNAPDRAGON
+	help
+	  Support for Qualcomm QUP I2C controller based on Qualcomm Universal
+	  Peripherals (QUP) engine. The QUP engine is an advanced high
+	  performance slave port that provides a common data path (an output
+	  FIFO and an input FIFO) for I2C and SPI interfaces. The I2C/SPI QUP
+	  controller is publicly documented in the Snapdragon 410E (APQ8016E)
+	  Technical Reference Manual, chapter "6.1 Qualcomm Universal
+	  Peripherals Engine (QUP)".
+
 config SYS_I2C_S3C24X0
 	bool "Samsung I2C driver"
 	depends on (ARCH_EXYNOS4 || ARCH_EXYNOS5) && DM_I2C
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 920aafb91c..b024547959 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_SYS_I2C_NPCM) += npcm_i2c.o
 obj-$(CONFIG_SYS_I2C_OCORES) += ocores_i2c.o
 obj-$(CONFIG_SYS_I2C_OCTEON) += octeon_i2c.o
 obj-$(CONFIG_SYS_I2C_OMAP24XX) += omap24xx_i2c.o
+obj-$(CONFIG_SYS_I2C_QUP) += qup_i2c.o
 obj-$(CONFIG_SYS_I2C_RCAR_I2C) += rcar_i2c.o
 obj-$(CONFIG_SYS_I2C_RCAR_IIC) += rcar_iic.o
 obj-$(CONFIG_SYS_I2C_ROCKCHIP) += rk_i2c.o
diff --git a/drivers/i2c/qup_i2c.c b/drivers/i2c/qup_i2c.c
new file mode 100644
index 0000000000..5ae3cccd4a
--- /dev/null
+++ b/drivers/i2c/qup_i2c.c
@@ -0,0 +1,579 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2009-2013, 2016-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2014, Sony Mobile Communications AB.
+ * Copyright (c) 2022-2023, Sumit Garg <sumit.garg at linaro.org>
+ *
+ * Inspired by corresponding driver in Linux: drivers/i2c/busses/i2c-qup.c
+ */
+
+#include <init.h>
+#include <env.h>
+#include <common.h>
+#include <log.h>
+#include <dm/device_compat.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/compat.h>
+#include <linux/bitops.h>
+#include <asm/io.h>
+#include <i2c.h>
+#include <watchdog.h>
+#include <fdtdec.h>
+#include <clk.h>
+#include <reset.h>
+#include <asm/arch/gpio.h>
+#include <cpu_func.h>
+#include <asm/system.h>
+#include <asm/gpio.h>
+#include <dm.h>
+#include <dm/pinctrl.h>
+
+/* QUP Registers */
+#define QUP_CONFIG				0x000
+#define QUP_STATE				0x004
+#define QUP_IO_MODE				0x008
+#define QUP_SW_RESET				0x00c
+#define QUP_OPERATIONAL				0x018
+#define QUP_ERROR_FLAGS				0x01c /* NOT USED */
+#define QUP_ERROR_FLAGS_EN			0x020 /* NOT USED */
+#define QUP_TEST_CTRL				0x024 /* NOT USED */
+#define QUP_OPERATIONAL_MASK			0x028 /* NOT USED */
+#define QUP_HW_VERSION				0x030
+#define QUP_MX_OUTPUT_CNT			0x100
+#define QUP_OUT_DEBUG				0x108 /* NOT USED */
+#define QUP_OUT_FIFO_CNT			0x10C /* NOT USED */
+#define QUP_OUT_FIFO_BASE			0x110
+#define QUP_MX_WRITE_CNT			0x150
+#define QUP_MX_INPUT_CNT			0x200
+#define QUP_MX_READ_CNT				0x208
+#define QUP_IN_READ_CUR				0x20C /* NOT USED */
+#define QUP_IN_DEBUG				0x210 /* NOT USED */
+#define QUP_IN_FIFO_CNT				0x214 /* NOT USED */
+#define QUP_IN_FIFO_BASE			0x218
+#define QUP_I2C_CLK_CTL				0x400
+#define QUP_I2C_STATUS				0x404 /* NOT USED */
+#define QUP_I2C_MASTER_GEN			0x408
+#define QUP_I2C_MASTER_BUS_CLR			0x40C /* NOT USED */
+
+/* QUP States and reset values */
+#define QUP_RESET_STATE				0
+#define QUP_RUN_STATE				1
+#define QUP_PAUSE_STATE				3
+#define QUP_STATE_MASK				3
+
+#define QUP_STATE_VALID				BIT(2)
+#define QUP_I2C_MAST_GEN			BIT(4)
+#define QUP_I2C_FLUSH				BIT(6)
+
+#define QUP_OPERATIONAL_RESET			0x000ff0
+#define QUP_I2C_STATUS_RESET			0xfffffc
+
+/* QUP OPERATIONAL FLAGS */
+#define QUP_I2C_NACK_FLAG			BIT(3)
+#define QUP_OUT_NOT_EMPTY			BIT(4)
+#define QUP_IN_NOT_EMPTY			BIT(5)
+#define QUP_OUT_FULL				BIT(6)
+#define QUP_OUT_SVC_FLAG			BIT(8)
+#define QUP_IN_SVC_FLAG				BIT(9)
+#define QUP_MX_OUTPUT_DONE			BIT(10)
+#define QUP_MX_INPUT_DONE			BIT(11)
+#define OUT_BLOCK_WRITE_REQ			BIT(12)
+#define IN_BLOCK_READ_REQ			BIT(13)
+
+/*
+ * QUP engine acting as I2C controller is referred to as
+ * I2C mini core, following are related macros.
+ */
+#define QUP_NO_OUTPUT				BIT(6)
+#define QUP_NO_INPUT				BIT(7)
+#define QUP_CLOCK_AUTO_GATE			BIT(13)
+#define QUP_I2C_MINI_CORE			(2 << 8)
+#define QUP_I2C_N_VAL_V2			7
+
+/* Packing/Unpacking words in FIFOs, and IO modes */
+#define QUP_OUTPUT_BLK_MODE			BIT(10)
+#define QUP_OUTPUT_BAM_MODE			(BIT(10) | BIT(11))
+#define QUP_INPUT_BLK_MODE			BIT(12)
+#define QUP_INPUT_BAM_MODE			(BIT(12) | BIT(13))
+#define QUP_BAM_MODE				(QUP_OUTPUT_BAM_MODE | QUP_INPUT_BAM_MODE)
+#define QUP_BLK_MODE				(QUP_OUTPUT_BLK_MODE | QUP_INPUT_BLK_MODE)
+#define QUP_UNPACK_EN				BIT(14)
+#define QUP_PACK_EN				BIT(15)
+
+#define QUP_REPACK_EN				(QUP_UNPACK_EN | QUP_PACK_EN)
+#define QUP_V2_TAGS_EN				1
+
+#define QUP_OUTPUT_BLOCK_SIZE(x)		(((x) >> 0) & 0x03)
+#define QUP_OUTPUT_FIFO_SIZE(x)			(((x) >> 2) & 0x07)
+#define QUP_INPUT_BLOCK_SIZE(x)			(((x) >> 5) & 0x03)
+#define QUP_INPUT_FIFO_SIZE(x)			(((x) >> 7) & 0x07)
+
+/* QUP v2 tags */
+#define QUP_TAG_V2_START			0x81
+#define QUP_TAG_V2_DATAWR			0x82
+#define QUP_TAG_V2_DATAWR_STOP			0x83
+#define QUP_TAG_V2_DATARD			0x85
+#define QUP_TAG_V2_DATARD_NACK			0x86
+#define QUP_TAG_V2_DATARD_STOP			0x87
+
+#define QUP_I2C_MX_CONFIG_DURING_RUN		BIT(31)
+
+/* Minimum transfer timeout for i2c transfers in micro seconds */
+#define TOUT_CNT				(2 * 1000 * 1000)
+
+/* Default values. Use these if FW query fails */
+#define DEFAULT_CLK_FREQ			I2C_SPEED_STANDARD_RATE
+#define DEFAULT_SRC_CLK				19200000
+
+/*
+ * Max tags length (start, stop and maximum 2 bytes address) for each QUP
+ * data transfer
+ */
+#define QUP_MAX_TAGS_LEN			4
+/* Max data length for each DATARD tags */
+#define RECV_MAX_DATA_LEN			254
+/* TAG length for DATA READ in RX FIFO */
+#define READ_RX_TAGS_LEN			2
+
+struct qup_i2c_priv {
+	phys_addr_t base;
+	struct clk core;
+	struct clk iface;
+	u32 in_fifo_sz;
+	u32 out_fifo_sz;
+	u32 clk_ctl;
+	u32 config_run;
+};
+
+static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
+{
+	return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
+}
+
+static int qup_i2c_poll_state_mask(struct qup_i2c_priv *qup,
+				   u32 req_state, u32 req_mask)
+{
+	int retries = 1;
+	u32 state;
+
+	/*
+	 * State transition takes 3 AHB clocks cycles + 3 I2C master clock
+	 * cycles. So retry once after a 1uS delay.
+	 */
+	do {
+		state = readl(qup->base + QUP_STATE);
+
+		if (state & QUP_STATE_VALID &&
+		    (state & req_mask) == req_state)
+			return 0;
+
+		udelay(1);
+	} while (retries--);
+
+	return -ETIMEDOUT;
+}
+
+static int qup_i2c_poll_state(struct qup_i2c_priv *qup, u32 req_state)
+{
+	return qup_i2c_poll_state_mask(qup, req_state, QUP_STATE_MASK);
+}
+
+static int qup_i2c_poll_state_valid(struct qup_i2c_priv *qup)
+{
+	return qup_i2c_poll_state_mask(qup, 0, 0);
+}
+
+static int qup_i2c_poll_state_i2c_master(struct qup_i2c_priv *qup)
+{
+	return qup_i2c_poll_state_mask(qup, QUP_I2C_MAST_GEN, QUP_I2C_MAST_GEN);
+}
+
+static int qup_i2c_change_state(struct qup_i2c_priv *qup, u32 state)
+{
+	if (qup_i2c_poll_state_valid(qup) != 0)
+		return -EIO;
+
+	writel(state, qup->base + QUP_STATE);
+
+	if (qup_i2c_poll_state(qup, state) != 0)
+		return -EIO;
+	return 0;
+}
+
+/*
+ * Function to check wheather Input or Output FIFO
+ * has data to be serviced
+ */
+static int qup_i2c_check_fifo_status(struct qup_i2c_priv *qup, u32 reg_addr,
+				     u32 flags)
+{
+	unsigned long count = TOUT_CNT;
+	u32 val, status_flag;
+	int ret = 0;
+
+	do {
+		val = readl(qup->base + reg_addr);
+		status_flag = val & flags;
+
+		if (!count) {
+			printf("%s, timeout\n", __func__);
+			ret = -ETIMEDOUT;
+			break;
+		}
+
+		count--;
+		udelay(1);
+	} while (!status_flag);
+
+	return ret;
+}
+
+/*
+ * Function to configure Input and Output enable/disable
+ */
+static void qup_i2c_enable_io_config(struct qup_i2c_priv *qup, u32 write_cnt,
+				     u32 read_cnt)
+{
+	u32 qup_config = QUP_I2C_MINI_CORE | QUP_I2C_N_VAL_V2;
+
+	writel(qup->config_run | write_cnt, qup->base + QUP_MX_WRITE_CNT);
+
+	if (read_cnt)
+		writel(qup->config_run | read_cnt, qup->base + QUP_MX_READ_CNT);
+	else
+		qup_config |= QUP_NO_INPUT;
+
+	writel(qup_config, qup->base + QUP_CONFIG);
+}
+
+static unsigned int qup_i2c_read_word(struct qup_i2c_priv *qup)
+{
+	return readl(qup->base + QUP_IN_FIFO_BASE);
+}
+
+static void qup_i2c_write_word(struct qup_i2c_priv *qup, u32 word)
+{
+	writel(word, qup->base + QUP_OUT_FIFO_BASE);
+}
+
+static int qup_i2c_blsp_read(struct qup_i2c_priv *qup, unsigned int addr,
+			     bool last, u8 *buffer, unsigned int bytes)
+{
+	unsigned int i, j, word;
+	int ret = 0;
+
+	/* FIFO mode size limitation, for larger size implement block mode */
+	if (bytes > (qup->in_fifo_sz - READ_RX_TAGS_LEN))
+		return -EINVAL;
+
+	qup_i2c_enable_io_config(qup, QUP_MAX_TAGS_LEN,
+				 bytes + READ_RX_TAGS_LEN);
+
+	if (last)
+		qup_i2c_write_word(qup, QUP_TAG_V2_START | addr << 8 |
+					QUP_TAG_V2_DATARD_STOP << 16 |
+					bytes << 24);
+	else
+		qup_i2c_write_word(qup, QUP_TAG_V2_START | addr << 8 |
+					QUP_TAG_V2_DATARD << 16 | bytes << 24);
+
+	ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+	if (ret)
+		return ret;
+
+	ret = qup_i2c_check_fifo_status(qup, QUP_OPERATIONAL, QUP_OUT_SVC_FLAG);
+	if (ret)
+		return ret;
+	writel(QUP_OUT_SVC_FLAG, qup->base + QUP_OPERATIONAL);
+
+	ret = qup_i2c_check_fifo_status(qup, QUP_OPERATIONAL, QUP_IN_SVC_FLAG);
+	if (ret)
+		return ret;
+	writel(QUP_IN_SVC_FLAG, qup->base + QUP_OPERATIONAL);
+
+	word = qup_i2c_read_word(qup);
+	*(buffer++) = (word >> (8 * READ_RX_TAGS_LEN)) & 0xff;
+	if (bytes > 1)
+		*(buffer++) = (word >> (8 * (READ_RX_TAGS_LEN + 1))) & 0xff;
+
+	for (i = 2; i < bytes; i += 4) {
+		word = qup_i2c_read_word(qup);
+
+		for (j = 0; j < 4; j++) {
+			if ((i + j) == bytes)
+				break;
+			*buffer = (word >> (j * 8)) & 0xff;
+			buffer++;
+		}
+	}
+
+	ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
+	return ret;
+}
+
+static int qup_i2c_blsp_write(struct qup_i2c_priv *qup, unsigned int addr,
+			      bool first, bool last, const u8 *buffer,
+			      unsigned int bytes)
+{
+	unsigned int i;
+	u32 word = 0;
+	int ret = 0;
+
+	/* FIFO mode size limitation, for larger size implement block mode */
+	if (bytes > (qup->out_fifo_sz - QUP_MAX_TAGS_LEN))
+		return -EINVAL;
+
+	qup_i2c_enable_io_config(qup, bytes + QUP_MAX_TAGS_LEN, 0);
+
+	if (first) {
+		ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+		if (ret)
+			return ret;
+
+		writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);
+
+		ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
+		if (ret)
+			return ret;
+	}
+
+	if (last)
+		qup_i2c_write_word(qup, QUP_TAG_V2_START | addr << 8 |
+					QUP_TAG_V2_DATAWR_STOP << 16 |
+					bytes << 24);
+	else
+		qup_i2c_write_word(qup, QUP_TAG_V2_START | addr << 8 |
+					QUP_TAG_V2_DATAWR << 16 | bytes << 24);
+
+	for (i = 0; i < bytes; i++) {
+		/* Write the byte of data */
+		word |= *buffer << ((i % 4) * 8);
+		if ((i % 4) == 3) {
+			qup_i2c_write_word(qup, word);
+			word = 0;
+		}
+		buffer++;
+	}
+
+	if ((i % 4) != 0)
+		qup_i2c_write_word(qup, word);
+
+	ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
+	if (ret)
+		return ret;
+
+	ret = qup_i2c_check_fifo_status(qup, QUP_OPERATIONAL, QUP_OUT_SVC_FLAG);
+	if (ret)
+		return ret;
+	writel(QUP_OUT_SVC_FLAG, qup->base + QUP_OPERATIONAL);
+
+	ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
+	return ret;
+}
+
+static void qup_i2c_conf_mode_v2(struct qup_i2c_priv *qup)
+{
+	u32 io_mode = QUP_REPACK_EN;
+
+	writel(0, qup->base + QUP_MX_OUTPUT_CNT);
+	writel(0, qup->base + QUP_MX_INPUT_CNT);
+
+	writel(io_mode, qup->base + QUP_IO_MODE);
+}
+
+static int qup_i2c_xfer_v2(struct udevice *bus, struct i2c_msg msgs[], int num)
+{
+	struct qup_i2c_priv *qup = dev_get_priv(bus);
+	int ret, idx = 0;
+	u32 i2c_addr;
+
+	writel(1, qup->base + QUP_SW_RESET);
+	ret = qup_i2c_poll_state(qup, QUP_RESET_STATE);
+	if (ret)
+		goto out;
+
+	/* Configure QUP as I2C mini core */
+	writel(QUP_I2C_MINI_CORE | QUP_I2C_N_VAL_V2 | QUP_NO_INPUT,
+	       qup->base + QUP_CONFIG);
+	writel(QUP_V2_TAGS_EN, qup->base + QUP_I2C_MASTER_GEN);
+
+	if (qup_i2c_poll_state_i2c_master(qup)) {
+		ret = -EIO;
+		goto out;
+	}
+
+	qup_i2c_conf_mode_v2(qup);
+
+	for (idx = 0; idx < num; idx++) {
+		struct i2c_msg *m = &msgs[idx];
+
+		qup->config_run = !idx ? 0 : QUP_I2C_MX_CONFIG_DURING_RUN;
+		i2c_addr = i2c_8bit_addr_from_msg(m);
+
+		if (m->flags & I2C_M_RD)
+			ret = qup_i2c_blsp_read(qup, i2c_addr, idx == (num - 1),
+						m->buf, m->len);
+		else
+			ret = qup_i2c_blsp_write(qup, i2c_addr, idx == 0,
+						 idx == (num - 1), m->buf,
+						 m->len);
+		if (ret)
+			break;
+	}
+out:
+	qup_i2c_change_state(qup, QUP_RESET_STATE);
+	return ret;
+}
+
+static int qup_i2c_enable_clocks(struct udevice *dev, struct qup_i2c_priv *qup)
+{
+	int ret;
+
+	ret = clk_enable(&qup->core);
+	if (ret) {
+		dev_err(dev, "clk_enable failed %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_enable(&qup->iface);
+	if (ret) {
+		dev_err(dev, "clk_enable failed %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int qup_i2c_probe(struct udevice *dev)
+{
+	static const int blk_sizes[] = {4, 16, 32};
+	struct qup_i2c_priv *qup = dev_get_priv(dev);
+	u32 io_mode, hw_ver, size, size_idx;
+	int ret;
+
+	qup->base = (phys_addr_t)dev_read_addr_ptr(dev);
+	if (!qup->base)
+		return -EINVAL;
+
+	ret = clk_get_by_name(dev, "core", &qup->core);
+	if (ret) {
+		pr_err("clk_get_by_name(core) failed: %d\n", ret);
+		return ret;
+	}
+	ret = clk_get_by_name(dev, "iface", &qup->iface);
+	if (ret) {
+		pr_err("clk_get_by_name(iface) failed: %d\n", ret);
+		return ret;
+	}
+	qup_i2c_enable_clocks(dev, qup);
+
+	writel(1, qup->base + QUP_SW_RESET);
+	ret = qup_i2c_poll_state_valid(qup);
+	if (ret)
+		return ret;
+
+	hw_ver = readl(qup->base + QUP_HW_VERSION);
+	dev_dbg(dev, "Revision %x\n", hw_ver);
+
+	io_mode = readl(qup->base + QUP_IO_MODE);
+
+	/*
+	 * The block/fifo size w.r.t. 'actual data' is 1/2 due to 'tag'
+	 * associated with each byte written/received
+	 */
+	size_idx = QUP_OUTPUT_BLOCK_SIZE(io_mode);
+	if (size_idx >= ARRAY_SIZE(blk_sizes)) {
+		ret = -EIO;
+		return ret;
+	}
+	size = QUP_OUTPUT_FIFO_SIZE(io_mode);
+	qup->out_fifo_sz = blk_sizes[size_idx] * (2 << size);
+
+	size_idx = QUP_INPUT_BLOCK_SIZE(io_mode);
+	if (size_idx >= ARRAY_SIZE(blk_sizes)) {
+		ret = -EIO;
+		return ret;
+	}
+	size = QUP_INPUT_FIFO_SIZE(io_mode);
+	qup->in_fifo_sz = blk_sizes[size_idx] * (2 << size);
+
+	dev_dbg(dev, "IN:fifo:%d, OUT:fifo:%d\n", qup->in_fifo_sz,
+		qup->out_fifo_sz);
+
+	return 0;
+}
+
+static int qup_i2c_set_bus_speed(struct udevice *dev, unsigned int clk_freq)
+{
+	struct qup_i2c_priv *qup = dev_get_priv(dev);
+	unsigned int src_clk_freq;
+	int fs_div, hs_div;
+
+	/* We support frequencies up to FAST Mode Plus (1MHz) */
+	if (!clk_freq || clk_freq > I2C_SPEED_FAST_PLUS_RATE) {
+		dev_err(dev, "clock frequency not supported %d\n", clk_freq);
+		return -EINVAL;
+	}
+
+	src_clk_freq = clk_get_rate(&qup->iface);
+	if ((int)src_clk_freq < 0) {
+		src_clk_freq = DEFAULT_SRC_CLK;
+		dev_dbg(dev, "using default core freq %d\n", src_clk_freq);
+	}
+
+	dev_dbg(dev, "src_clk_freq %u\n", src_clk_freq);
+	dev_dbg(dev, "clk_freq     %u\n", clk_freq);
+
+	hs_div = 3;
+	if (clk_freq <= I2C_SPEED_STANDARD_RATE) {
+		fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
+		qup->clk_ctl = (hs_div << 8) | (fs_div & 0xff);
+	} else {
+		/* 33%/66% duty cycle */
+		fs_div = ((src_clk_freq / clk_freq) - 6) * 2 / 3;
+		qup->clk_ctl = ((fs_div / 2) << 16) | (hs_div << 8) | (fs_div & 0xff);
+	}
+
+	dev_dbg(dev, "clk_ctl      %u\n", qup->clk_ctl);
+
+	return 0;
+}
+
+/* Probe to see if a chip is present. */
+static int qup_i2c_probe_chip(struct udevice *dev, uint chip_addr,
+			      uint chip_flags)
+{
+	struct qup_i2c_priv *qup = dev_get_priv(dev);
+	u32 hw_ver = readl(qup->base + QUP_HW_VERSION);
+
+	return hw_ver ? 0 : -1;
+}
+
+static const struct dm_i2c_ops qup_i2c_ops = {
+	.xfer		= qup_i2c_xfer_v2,
+	.probe_chip	= qup_i2c_probe_chip,
+	.set_bus_speed	= qup_i2c_set_bus_speed,
+};
+
+/*
+ * Currently this driver only supports v2.x of QUP I2C controller, hence
+ * functions above are named with a _v2 suffix. So when we have the
+ * v1.1.1 support added as per the Linux counterpart then it should be easy
+ * to add corresponding functions named with a _v1 suffix.
+ */
+static const struct udevice_id qup_i2c_ids[] = {
+	{ .compatible = "qcom,i2c-qup-v2.1.1" },
+	{ .compatible = "qcom,i2c-qup-v2.2.1" },
+	{}
+};
+
+U_BOOT_DRIVER(i2c_qup) = {
+	.name	= "i2c_qup",
+	.id	= UCLASS_I2C,
+	.of_match = qup_i2c_ids,
+	.probe	= qup_i2c_probe,
+	.priv_auto = sizeof(struct qup_i2c_priv),
+	.ops	= &qup_i2c_ops,
+};
-- 
2.34.1



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