[PATCH v2] i2c: add Rockchip i2c controller support

Ahmad Fatoum a.fatoum at pengutronix.de
Fri Jan 14 00:54:25 PST 2022 

For addressing the PMIC on Rockchip platforms, add an i2c controller
driver. Tested with rk3399 and rk808.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
v1 -> v2:
  - remove unneeded udelay(1)s (Sascha)
  - use readl_poll_timeout
  - fix typos, copy-paste leftovers (Sascha)
  - early exit on NAK (Sascha)
---
 drivers/i2c/busses/Kconfig        |   8 +
 drivers/i2c/busses/Makefile       |   1 +
 drivers/i2c/busses/i2c-rockchip.c | 458 ++++++++++++++++++++++++++++++
 3 files changed, 467 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-rockchip.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index c1e76a04096e..a551df537a69 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -62,4 +62,12 @@ config I2C_STM32
 	depends on HAVE_CLK
 	depends on ARCH_STM32MP || COMPILE_TEST
 
+config I2C_RK3X
+	tristate "Rockchip RK3xxx I2C adapter"
+	depends on HAVE_CLK
+	depends on ARCH_ROCKCHIP || COMPILE_TEST
+	help
+	  Say Y here to include support for the I2C adapter in Rockchip RK3xxx
+	  SoCs.
+
 endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 34a12fcbea96..d6273f3d8679 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 obj-$(CONFIG_I2C_DESIGNWARE)	+= i2c-designware.o
 obj-$(CONFIG_I2C_STM32)		+= i2c-stm32.o
+obj-$(CONFIG_I2C_RK3X)		+= i2c-rockchip.o
diff --git a/drivers/i2c/busses/i2c-rockchip.c b/drivers/i2c/busses/i2c-rockchip.c
new file mode 100644
index 000000000000..4990735a4b11
--- /dev/null
+++ b/drivers/i2c/busses/i2c-rockchip.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2014 Rockchip Electronics
+ * Peter, Software Engineering, <superpeter.cai at gmail.com>.
+ */
+
+#include <common.h>
+#include <i2c/i2c.h>
+#include <linux/iopoll.h>
+#include <errno.h>
+#include <linux/err.h>
+#include <driver.h>
+#include <io.h>
+#include <linux/clk.h>
+#include <mfd/syscon.h>
+#include <regmap.h>
+#include <linux/sizes.h>
+
+struct i2c_regs {
+	u32 con;
+	u32 clkdiv;
+	u32 mrxaddr;
+	u32 mrxraddr;
+	u32 mtxcnt;
+	u32 mrxcnt;
+	u32 ien;
+	u32 ipd;
+	u32 fcnt;
+	u32 reserved0[0x37];
+	u32 txdata[8];
+	u32 reserved1[0x38];
+	u32 rxdata[8];
+};
+
+/* Control register */
+#define I2C_CON_EN		(1 << 0)
+#define I2C_CON_MOD(mod)	((mod) << 1)
+#define I2C_MODE_TX		0x00
+#define I2C_MODE_TRX		0x01
+#define I2C_MODE_RX		0x02
+#define I2C_MODE_RRX		0x03
+#define I2C_CON_MASK		(3 << 1)
+
+#define I2C_CON_START		(1 << 3)
+#define I2C_CON_STOP		(1 << 4)
+#define I2C_CON_LASTACK		(1 << 5)
+#define I2C_CON_ACTACK		(1 << 6)
+
+/* Clock divider register */
+#define I2C_CLKDIV_VAL(divl, divh) \
+	(((divl) & 0xffff) | (((divh) << 16) & 0xffff0000))
+
+/* the slave address accessed  for master rx mode */
+#define I2C_MRXADDR_SET(vld, addr)	(((vld) << 24) | (addr))
+
+/* the slave register address accessed  for master rx mode */
+#define I2C_MRXRADDR_SET(vld, raddr)	(((vld) << 24) | (raddr))
+
+/* interrupt enable register */
+#define I2C_BTFIEN		(1 << 0)
+#define I2C_BRFIEN		(1 << 1)
+#define I2C_MBTFIEN		(1 << 2)
+#define I2C_MBRFIEN		(1 << 3)
+#define I2C_STARTIEN		(1 << 4)
+#define I2C_STOPIEN		(1 << 5)
+#define I2C_NAKRCVIEN		(1 << 6)
+
+/* interrupt pending register */
+#define I2C_BTFIPD              (1 << 0)
+#define I2C_BRFIPD              (1 << 1)
+#define I2C_MBTFIPD             (1 << 2)
+#define I2C_MBRFIPD             (1 << 3)
+#define I2C_STARTIPD            (1 << 4)
+#define I2C_STOPIPD             (1 << 5)
+#define I2C_NAKRCVIPD           (1 << 6)
+#define I2C_IPD_ALL_CLEAN       0x7f
+
+/* i2c timeout */
+#define I2C_TIMEOUT_US		(100 * USEC_PER_MSEC)
+
+/* rk i2c fifo max transfer bytes */
+#define RK_I2C_FIFO_SIZE	32
+
+struct rk_i2c {
+	struct i2c_adapter	adapter;
+	struct clk *clk;
+	struct i2c_regs *regs;
+	unsigned int speed;
+};
+
+static inline struct rk_i2c *to_rk_i2c(struct i2c_adapter *adapter)
+{
+	return container_of(adapter, struct rk_i2c, adapter);
+}
+
+static inline void rk_i2c_get_div(int div, int *divh, int *divl)
+{
+	*divl = div / 2;
+	*divh = DIV_ROUND_UP(div, 2);
+}
+
+/*
+ * SCL Divisor = 8 * (CLKDIVL+1 + CLKDIVH+1)
+ * SCL = PCLK / SCLK Divisor
+ * i2c_rate = PCLK
+ */
+static void rk_i2c_set_clk(struct rk_i2c *i2c, uint32_t scl_rate)
+{
+	struct device_d *dev = i2c->adapter.dev.parent;
+	uint32_t i2c_rate;
+	int div, divl, divh;
+
+	/* First get i2c rate from pclk */
+	i2c_rate = clk_get_rate(i2c->clk);
+
+	div = DIV_ROUND_UP(i2c_rate, scl_rate * 8) - 2;
+	divh = 0;
+	divl = 0;
+	if (div >= 0)
+		rk_i2c_get_div(div, &divh, &divl);
+	writel(I2C_CLKDIV_VAL(divl, divh), &i2c->regs->clkdiv);
+
+	dev_dbg(dev, "rk_i2c_set_clk: i2c rate = %d, scl rate = %d\n", i2c_rate,
+		scl_rate);
+	dev_dbg(dev, "set i2c clk div = %d, divh = %d, divl = %d\n", div, divh, divl);
+	dev_dbg(dev, "set clk(I2C_CLKDIV: 0x%08x)\n", readl(&i2c->regs->clkdiv));
+}
+
+static void rk_i2c_show_regs(struct rk_i2c *i2c)
+{
+	struct device_d *dev = &i2c->adapter.dev;
+	struct i2c_regs *regs = i2c->regs;
+	int i;
+
+	dev_dbg(dev, "i2c_con: 0x%08x\n", readl(&regs->con));
+	dev_dbg(dev, "i2c_clkdiv: 0x%08x\n", readl(&regs->clkdiv));
+	dev_dbg(dev, "i2c_mrxaddr: 0x%08x\n", readl(&regs->mrxaddr));
+	dev_dbg(dev, "i2c_mrxraddR: 0x%08x\n", readl(&regs->mrxraddr));
+	dev_dbg(dev, "i2c_mtxcnt: 0x%08x\n", readl(&regs->mtxcnt));
+	dev_dbg(dev, "i2c_mrxcnt: 0x%08x\n", readl(&regs->mrxcnt));
+	dev_dbg(dev, "i2c_ien: 0x%08x\n", readl(&regs->ien));
+	dev_dbg(dev, "i2c_ipd: 0x%08x\n", readl(&regs->ipd));
+	dev_dbg(dev, "i2c_fcnt: 0x%08x\n", readl(&regs->fcnt));
+
+	for (i = 0; i < 8; i++)
+		dev_dbg(dev, "i2c_txdata%d: 0x%08x\n", i, readl(&regs->txdata[i]));
+	for (i = 0; i < 8; i++)
+		dev_dbg(dev, "i2c_rxdata%d: 0x%08x\n", i, readl(&regs->rxdata[i]));
+}
+
+static int rk_i2c_send_start_bit(struct rk_i2c *i2c)
+{
+	struct device_d *dev = &i2c->adapter.dev;
+	struct i2c_regs *regs = i2c->regs;
+	u32 val;
+	int err;
+
+	dev_dbg(dev, "I2c Send Start bit.\n");
+	writel(I2C_IPD_ALL_CLEAN, &regs->ipd);
+
+	writel(I2C_CON_EN | I2C_CON_START, &regs->con);
+	writel(I2C_STARTIEN, &regs->ien);
+
+	err = readl_poll_timeout(&regs->ipd, val, val & I2C_STARTIPD, I2C_TIMEOUT_US);
+	if (err) {
+		dev_dbg(dev, "I2C Send Start Bit Timeout\n");
+		rk_i2c_show_regs(i2c);
+		return err;
+	}
+
+	writel(I2C_STARTIPD, &regs->ipd);
+	return 0;
+}
+
+static int rk_i2c_send_stop_bit(struct rk_i2c *i2c)
+{
+	struct device_d *dev = &i2c->adapter.dev;
+	struct i2c_regs *regs = i2c->regs;
+	u32 val;
+	int err;
+
+	dev_dbg(dev, "I2c Send Stop bit.\n");
+	writel(I2C_IPD_ALL_CLEAN, &regs->ipd);
+
+	writel(I2C_CON_EN | I2C_CON_STOP, &regs->con);
+	writel(I2C_CON_STOP, &regs->ien);
+
+	err = readl_poll_timeout(&regs->ipd, val, val & I2C_STOPIPD, I2C_TIMEOUT_US);
+	if (err) {
+		dev_dbg(dev, "I2C Send Start Bit Timeout\n");
+		rk_i2c_show_regs(i2c);
+		return err;
+	}
+
+	writel(I2C_STOPIPD, &regs->ipd);
+	return 0;
+}
+
+static inline void rk_i2c_disable(struct rk_i2c *i2c)
+{
+	writel(0, &i2c->regs->con);
+}
+
+static int rk_i2c_read(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len,
+		       uchar *buf, uint b_len)
+{
+	struct device_d *dev = &i2c->adapter.dev;
+	struct i2c_regs *regs = i2c->regs;
+	uchar *pbuf = buf;
+	uint bytes_remain_len = b_len;
+	uint bytes_xferred = 0;
+	uint words_xferred = 0;
+	uint con = 0;
+	uint rxdata;
+	uint i, j;
+	int err;
+	u32 val;
+	bool snd_chunk = false;
+
+	dev_dbg(dev, "rk_i2c_read: chip = %d, reg = %d, r_len = %d, b_len = %d\n",
+	      chip, reg, r_len, b_len);
+
+	err = rk_i2c_send_start_bit(i2c);
+	if (err)
+		return err;
+
+	writel(I2C_MRXADDR_SET(1, chip << 1 | 1), &regs->mrxaddr);
+	if (r_len == 0) {
+		writel(0, &regs->mrxraddr);
+	} else if (r_len < 4) {
+		writel(I2C_MRXRADDR_SET(r_len, reg), &regs->mrxraddr);
+	} else {
+		dev_dbg(dev, "I2C Read: addr len %d not supported\n", r_len);
+		return -EIO;
+	}
+
+	while (bytes_remain_len) {
+		if (bytes_remain_len > RK_I2C_FIFO_SIZE) {
+			con = I2C_CON_EN;
+			bytes_xferred = RK_I2C_FIFO_SIZE;
+		} else {
+			/*
+			 * The hw can read up to 32 bytes at a time. If we need
+			 * more than one chunk, send an ACK after the last byte.
+			 */
+			con = I2C_CON_EN | I2C_CON_LASTACK;
+			bytes_xferred = bytes_remain_len;
+		}
+		words_xferred = DIV_ROUND_UP(bytes_xferred, 4);
+
+		/*
+		 * make sure we are in plain RX mode if we read a second chunk
+		 */
+		if (snd_chunk)
+			con |= I2C_CON_MOD(I2C_MODE_RX);
+		else
+			con |= I2C_CON_MOD(I2C_MODE_TRX);
+
+		writel(con, &regs->con);
+		writel(bytes_xferred, &regs->mrxcnt);
+		writel(I2C_MBRFIEN | I2C_NAKRCVIEN, &regs->ien);
+
+		err = readl_poll_timeout(&regs->ipd, val, val & (I2C_NAKRCVIPD|I2C_MBRFIPD), I2C_TIMEOUT_US);
+		if (err) {
+			dev_dbg(dev, "I2C Read Data Timeout\n");
+			goto i2c_exit;
+		}
+
+		if (val & I2C_NAKRCVIPD) {
+			writel(I2C_NAKRCVIPD, &regs->ipd);
+			err = -EREMOTEIO;
+			goto i2c_exit;
+		}
+
+		writel(I2C_MBRFIPD, &regs->ipd);
+
+		for (i = 0; i < words_xferred; i++) {
+			rxdata = readl(&regs->rxdata[i]);
+			dev_dbg(dev, "I2c Read RXDATA[%d] = 0x%x\n", i, rxdata);
+			for (j = 0; j < 4; j++) {
+				if ((i * 4 + j) == bytes_xferred)
+					break;
+				*pbuf++ = (rxdata >> (j * 8)) & 0xff;
+			}
+		}
+
+		bytes_remain_len -= bytes_xferred;
+		snd_chunk = true;
+		dev_dbg(dev, "I2C Read bytes_remain_len %d\n", bytes_remain_len);
+	}
+
+i2c_exit:
+	if (err)
+		rk_i2c_show_regs(i2c);
+	rk_i2c_disable(i2c);
+
+	return err;
+}
+
+static int rk_i2c_write(struct rk_i2c *i2c, uchar chip, uint reg, uint r_len,
+			uchar *buf, uint b_len)
+{
+	struct device_d *dev = &i2c->adapter.dev;
+	struct i2c_regs *regs = i2c->regs;
+	u32 val;
+	int err;
+	uchar *pbuf = buf;
+	uint bytes_remain_len = b_len + r_len + 1;
+	uint bytes_xferred = 0;
+	uint words_xferred = 0;
+	uint txdata;
+	uint i, j;
+
+	dev_dbg(dev, "rk_i2c_write: chip = %d, reg = %d, r_len = %d, b_len = %d\n",
+	      chip, reg, r_len, b_len);
+	err = rk_i2c_send_start_bit(i2c);
+	if (err)
+		return err;
+
+	while (bytes_remain_len) {
+		if (bytes_remain_len > RK_I2C_FIFO_SIZE)
+			bytes_xferred = RK_I2C_FIFO_SIZE;
+		else
+			bytes_xferred = bytes_remain_len;
+		words_xferred = DIV_ROUND_UP(bytes_xferred, 4);
+
+		for (i = 0; i < words_xferred; i++) {
+			txdata = 0;
+			for (j = 0; j < 4; j++) {
+				if ((i * 4 + j) == bytes_xferred)
+					break;
+
+				if (i == 0 && j == 0 && pbuf == buf) {
+					txdata |= (chip << 1);
+				} else if (i == 0 && j <= r_len && pbuf == buf) {
+					txdata |= (reg &
+						(0xff << ((j - 1) * 8))) << 8;
+				} else {
+					txdata |= (*pbuf++)<<(j * 8);
+				}
+			}
+			writel(txdata, &regs->txdata[i]);
+			dev_dbg(dev, "I2c Write TXDATA[%d] = 0x%08x\n", i, txdata);
+		}
+
+		writel(I2C_CON_EN | I2C_CON_MOD(I2C_MODE_TX), &regs->con);
+		writel(bytes_xferred, &regs->mtxcnt);
+		writel(I2C_MBTFIEN | I2C_NAKRCVIEN, &regs->ien);
+
+		err = readl_poll_timeout(&regs->ipd, val, val & (I2C_NAKRCVIPD|I2C_MBTFIPD), I2C_TIMEOUT_US);
+		if (err) {
+			dev_dbg(dev, "I2C Write Data Timeout\n");
+			goto i2c_exit;
+		}
+
+		if (val & I2C_NAKRCVIPD) {
+			writel(I2C_NAKRCVIPD, &regs->ipd);
+			err = -EREMOTEIO;
+			goto i2c_exit;
+		}
+
+		writel(I2C_MBTFIPD, &regs->ipd);
+
+		bytes_remain_len -= bytes_xferred;
+		dev_dbg(dev, "I2C Write bytes_remain_len %d\n", bytes_remain_len);
+	}
+
+i2c_exit:
+	if (err)
+		rk_i2c_show_regs(i2c);
+	rk_i2c_disable(i2c);
+
+	return err;
+}
+
+static int rockchip_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msg,
+			     int nmsgs)
+{
+	struct rk_i2c *i2c = to_rk_i2c(adapter);
+	struct device_d *dev = &adapter->dev;
+	int ret;
+
+	dev_dbg(dev, "i2c_xfer: %d messages\n", nmsgs);
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		dev_dbg(dev, "i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
+		if (msg->flags & I2C_M_RD) {
+			ret = rk_i2c_read(i2c, msg->addr, 0, 0, msg->buf,
+					  msg->len);
+		} else {
+			ret = rk_i2c_write(i2c, msg->addr, 0, 0, msg->buf,
+					   msg->len);
+		}
+		if (ret) {
+			dev_dbg(dev, "i2c_write: error sending: %pe\n",
+				ERR_PTR(ret));
+			return -EREMOTEIO;
+		}
+	}
+
+	rk_i2c_send_stop_bit(i2c);
+	rk_i2c_disable(i2c);
+
+	return 0;
+}
+
+static int rk_i2c_probe(struct device_d *dev)
+{
+	struct device_node *np = dev->device_node;
+	struct resource *iores;
+	struct rk_i2c *i2c;
+	unsigned bitrate;
+
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+
+	i2c = kzalloc(sizeof(struct rk_i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	dev->priv = i2c;
+	i2c->regs = IOMEM(iores->start);
+
+	/* Only one clock to use for bus clock and peripheral clock */
+	i2c->clk = clk_get(dev, NULL);
+	if (IS_ERR(i2c->clk))
+		return dev_err_probe(dev, PTR_ERR(i2c->clk), "Can't get bus clk\n");
+
+	i2c->adapter.master_xfer = rockchip_i2c_xfer;
+	i2c->adapter.nr = dev->id;
+	i2c->adapter.dev.parent = dev;
+	i2c->adapter.dev.device_node = np;
+
+	/* Set up clock divider */
+	bitrate = 100000;
+	of_property_read_u32(np, "clock-frequency", &bitrate);
+
+	rk_i2c_set_clk(i2c, bitrate);
+
+	return i2c_add_numbered_adapter(&i2c->adapter);
+}
+
+static const struct of_device_id rk_i2c_match[] = {
+	{ .compatible = "rockchip,rv1108-i2c" },
+	{ .compatible = "rockchip,rk3228-i2c" },
+	{ .compatible = "rockchip,rk3288-i2c" },
+	{ .compatible = "rockchip,rk3399-i2c" },
+	{},
+};
+
+static struct driver_d rk_i2c_driver = {
+	.name  = "rk3x-i2c",
+	.of_compatible = rk_i2c_match,
+	.probe   = rk_i2c_probe,
+};
+coredevice_platform_driver(rk_i2c_driver);
-- 
2.30.2

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