linux-kernel - [PATCH] i2c: imx-lpi2c: add generic GPIO recovery for LPI2C

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Date: Mon, 26 Feb 2024 13:54:18 +0800
From: carlos.song@....com
To: andi.shyti@...nel.org,
	aisheng.dong@....com,
	shawnguo@...nel.org,
	s.hauer@...gutronix.de,
	kernel@...gutronix.de,
	festevam@...il.com
Cc: carlos.song@....com,
	xiaoning.wang@....com,
	haibo.chen@....com,
	linux-imx@....com,
	linux-i2c@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] i2c: imx-lpi2c: add generic GPIO recovery for LPI2C

From: Carlos Song <carlos.song@....com>

This adds i2c bus recovery to the lpi2c driver.

Uses the generic recovery function setting the SCL/SDA pads as
GPIO pins and sending 9 clocks to try and recover the bus.

Signed-off-by: Carlos Song <carlos.song@....com>
Reviewed-by: Clark Wang <xiaoning.wang@....com>
---
 drivers/i2c/busses/i2c-imx-lpi2c.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 678b30e90492..6d72e4e126dd 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -106,6 +106,7 @@ struct lpi2c_imx_struct {
 	unsigned int		txfifosize;
 	unsigned int		rxfifosize;
 	enum lpi2c_imx_mode	mode;
+	struct i2c_bus_recovery_info rinfo;
 };
 
 static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
@@ -133,6 +134,8 @@ static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx)
 
 		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
 			dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
+			if (lpi2c_imx->adapter.bus_recovery_info)
+				i2c_recover_bus(&lpi2c_imx->adapter);
 			return -ETIMEDOUT;
 		}
 		schedule();
@@ -190,6 +193,8 @@ static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
 
 		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
 			dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
+			if (lpi2c_imx->adapter.bus_recovery_info)
+				i2c_recover_bus(&lpi2c_imx->adapter);
 			break;
 		}
 		schedule();
@@ -325,6 +330,8 @@ static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
 
 		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
 			dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
+			if (lpi2c_imx->adapter.bus_recovery_info)
+				i2c_recover_bus(&lpi2c_imx->adapter);
 			return -ETIMEDOUT;
 		}
 		schedule();
@@ -526,6 +533,20 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int lpi2c_imx_init_recovery_info(struct lpi2c_imx_struct *lpi2c_imx,
+				  struct platform_device *pdev)
+{
+	struct i2c_bus_recovery_info *bri = &lpi2c_imx->rinfo;
+
+	bri->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(bri->pinctrl))
+		return PTR_ERR(bri->pinctrl);
+
+	lpi2c_imx->adapter.bus_recovery_info = bri;
+
+	return 0;
+}
+
 static u32 lpi2c_imx_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
@@ -600,6 +621,12 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
 	lpi2c_imx->txfifosize = 1 << (temp & 0x0f);
 	lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f);
 
+	/* Init optional bus recovery function */
+	ret = lpi2c_imx_init_recovery_info(lpi2c_imx, pdev);
+	/* Give it another chance if pinctrl used is not ready yet */
+	if (ret == -EPROBE_DEFER)
+		goto rpm_disable;
+
 	ret = i2c_add_adapter(&lpi2c_imx->adapter);
 	if (ret)
 		goto rpm_disable;
-- 
2.34.1