Linux-libre 4.4-gnupck-4.4-gnu

1 files changed, 73 insertions, 1 deletions

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 785aa674a..d4d853680 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -49,6 +49,8 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
+#include <linux/of_gpio.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_data/i2c-imx.h>
 #include <linux/platform_device.h>
 #include <linux/sched.h>
@@ -207,6 +209,11 @@ struct imx_i2c_struct {
 	unsigned int		cur_clk;
 	unsigned int		bitrate;
 	const struct imx_i2c_hwdata	*hwdata;
+	struct i2c_bus_recovery_info rinfo;
+
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pinctrl_pins_default;
+	struct pinctrl_state *pinctrl_pins_gpio;
 
 	struct imx_i2c_dma	*dma;
 };
@@ -461,7 +468,7 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
 {
 	if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
-		return -EIO;  /* No ACK */
+		return -ENXIO;  /* No ACK */
 	}
 
 	dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
@@ -896,6 +903,13 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
 
 	/* Start I2C transfer */
 	result = i2c_imx_start(i2c_imx);
+	if (result) {
+		if (i2c_imx->adapter.bus_recovery_info) {
+			i2c_recover_bus(&i2c_imx->adapter);
+			result = i2c_imx_start(i2c_imx);
+		}
+	}
+
 	if (result)
 		goto fail0;
 
@@ -956,6 +970,55 @@ fail0:
 	return (result < 0) ? result : num;
 }
 
+static void i2c_imx_prepare_recovery(struct i2c_adapter *adap)
+{
+	struct imx_i2c_struct *i2c_imx;
+
+	i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
+
+	pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_gpio);
+}
+
+static void i2c_imx_unprepare_recovery(struct i2c_adapter *adap)
+{
+	struct imx_i2c_struct *i2c_imx;
+
+	i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
+
+	pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_default);
+}
+
+static void i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
+		struct platform_device *pdev)
+{
+	struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
+
+	i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx->pinctrl,
+			PINCTRL_STATE_DEFAULT);
+	i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
+			"gpio");
+	rinfo->sda_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
+			"sda-gpios", 0, NULL);
+	rinfo->scl_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
+			"scl-gpios", 0, NULL);
+
+	if (!gpio_is_valid(rinfo->sda_gpio) ||
+	    !gpio_is_valid(rinfo->scl_gpio) ||
+	    IS_ERR(i2c_imx->pinctrl_pins_default) ||
+	    IS_ERR(i2c_imx->pinctrl_pins_gpio)) {
+		dev_dbg(&pdev->dev, "recovery information incomplete\n");
+		return;
+	}
+
+	dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
+			rinfo->sda_gpio, rinfo->scl_gpio);
+
+	rinfo->prepare_recovery = i2c_imx_prepare_recovery;
+	rinfo->unprepare_recovery = i2c_imx_unprepare_recovery;
+	rinfo->recover_bus = i2c_generic_gpio_recovery;
+	i2c_imx->adapter.bus_recovery_info = rinfo;
+}
+
 static u32 i2c_imx_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
@@ -1023,6 +1086,13 @@ static int i2c_imx_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "can't enable I2C clock\n");
 		return ret;
 	}
+
+	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(i2c_imx->pinctrl)) {
+		ret = PTR_ERR(i2c_imx->pinctrl);
+		goto clk_disable;
+	}
+
 	/* Request IRQ */
 	ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0,
 				pdev->name, i2c_imx);
@@ -1049,6 +1119,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
 			i2c_imx, IMX_I2C_I2CR);
 	imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
 
+	i2c_imx_init_recovery_info(i2c_imx, pdev);
+
 	/* Add I2C adapter */
 	ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
 	if (ret < 0) {