Merge branch 'for-wolfram' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio into i2c/for-4.15

Refactor i2c-gpio and its users to use gpiod. Done by GPIO maintainer
LinusW.

1 files changed, 104 insertions, 108 deletions

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index 0ef8fcc6ac3a..d80ea6ce91bb 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -14,27 +14,17 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/of.h>
-#include <linux/of_gpio.h>
 
 struct i2c_gpio_private_data {
+	struct gpio_desc *sda;
+	struct gpio_desc *scl;
 	struct i2c_adapter adap;
 	struct i2c_algo_bit_data bit_data;
 	struct i2c_gpio_platform_data pdata;
 };
 
-/* Toggle SDA by changing the direction of the pin */
-static void i2c_gpio_setsda_dir(void *data, int state)
-{
-	struct i2c_gpio_platform_data *pdata = data;
-
-	if (state)
-		gpio_direction_input(pdata->sda_pin);
-	else
-		gpio_direction_output(pdata->sda_pin, 0);
-}
-
 /*
  * Toggle SDA by changing the output value of the pin. This is only
  * valid for pins configured as open drain (i.e. setting the value
@@ -42,20 +32,9 @@ static void i2c_gpio_setsda_dir(void *data, int state)
  */
 static void i2c_gpio_setsda_val(void *data, int state)
 {
-	struct i2c_gpio_platform_data *pdata = data;
-
-	gpio_set_value(pdata->sda_pin, state);
-}
-
-/* Toggle SCL by changing the direction of the pin. */
-static void i2c_gpio_setscl_dir(void *data, int state)
-{
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	if (state)
-		gpio_direction_input(pdata->scl_pin);
-	else
-		gpio_direction_output(pdata->scl_pin, 0);
+	gpiod_set_value(priv->sda, state);
 }
 
 /*
@@ -66,44 +45,23 @@ static void i2c_gpio_setscl_dir(void *data, int state)
  */
 static void i2c_gpio_setscl_val(void *data, int state)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	gpio_set_value(pdata->scl_pin, state);
+	gpiod_set_value(priv->scl, state);
 }
 
 static int i2c_gpio_getsda(void *data)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	return gpio_get_value(pdata->sda_pin);
+	return gpiod_get_value(priv->sda);
 }
 
 static int i2c_gpio_getscl(void *data)
 {
-	struct i2c_gpio_platform_data *pdata = data;
-
-	return gpio_get_value(pdata->scl_pin);
-}
-
-static int of_i2c_gpio_get_pins(struct device_node *np,
-				unsigned int *sda_pin, unsigned int *scl_pin)
-{
-	if (of_gpio_count(np) < 2)
-		return -ENODEV;
-
-	*sda_pin = of_get_gpio(np, 0);
-	*scl_pin = of_get_gpio(np, 1);
-
-	if (*sda_pin == -EPROBE_DEFER || *scl_pin == -EPROBE_DEFER)
-		return -EPROBE_DEFER;
-
-	if (!gpio_is_valid(*sda_pin) || !gpio_is_valid(*scl_pin)) {
-		pr_err("%pOF: invalid GPIO pins, sda=%d/scl=%d\n",
-		       np, *sda_pin, *scl_pin);
-		return -ENODEV;
-	}
+	struct i2c_gpio_private_data *priv = data;
 
-	return 0;
+	return gpiod_get_value(priv->scl);
 }
 
 static void of_i2c_gpio_get_props(struct device_node *np,
@@ -124,72 +82,105 @@ static void of_i2c_gpio_get_props(struct device_node *np,
 		of_property_read_bool(np, "i2c-gpio,scl-output-only");
 }
 
+static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
+					   const char *con_id,
+					   unsigned int index,
+					   enum gpiod_flags gflags)
+{
+	struct gpio_desc *retdesc;
+	int ret;
+
+	retdesc = devm_gpiod_get(dev, con_id, gflags);
+	if (!IS_ERR(retdesc)) {
+		dev_dbg(dev, "got GPIO from name %s\n", con_id);
+		return retdesc;
+	}
+
+	retdesc = devm_gpiod_get_index(dev, NULL, index, gflags);
+	if (!IS_ERR(retdesc)) {
+		dev_dbg(dev, "got GPIO from index %u\n", index);
+		return retdesc;
+	}
+
+	ret = PTR_ERR(retdesc);
+
+	/* FIXME: hack in the old code, is this really necessary? */
+	if (ret == -EINVAL)
+		retdesc = ERR_PTR(-EPROBE_DEFER);
+
+	/* This happens if the GPIO driver is not yet probed, let's defer */
+	if (ret == -ENOENT)
+		retdesc = ERR_PTR(-EPROBE_DEFER);
+
+	if (ret != -EPROBE_DEFER)
+		dev_err(dev, "error trying to get descriptor: %d\n", ret);
+
+	return retdesc;
+}
+
 static int i2c_gpio_probe(struct platform_device *pdev)
 {
 	struct i2c_gpio_private_data *priv;
 	struct i2c_gpio_platform_data *pdata;
 	struct i2c_algo_bit_data *bit_data;
 	struct i2c_adapter *adap;
-	unsigned int sda_pin, scl_pin;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	enum gpiod_flags gflags;
 	int ret;
 
-	/* First get the GPIO pins; if it fails, we'll defer the probe. */
-	if (pdev->dev.of_node) {
-		ret = of_i2c_gpio_get_pins(pdev->dev.of_node,
-					   &sda_pin, &scl_pin);
-		if (ret)
-			return ret;
-	} else {
-		if (!dev_get_platdata(&pdev->dev))
-			return -ENXIO;
-		pdata = dev_get_platdata(&pdev->dev);
-		sda_pin = pdata->sda_pin;
-		scl_pin = pdata->scl_pin;
-	}
-
-	ret = devm_gpio_request(&pdev->dev, sda_pin, "sda");
-	if (ret) {
-		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;	/* Try again later */
-		return ret;
-	}
-	ret = devm_gpio_request(&pdev->dev, scl_pin, "scl");
-	if (ret) {
-		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;	/* Try again later */
-		return ret;
-	}
-
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
+
 	adap = &priv->adap;
 	bit_data = &priv->bit_data;
 	pdata = &priv->pdata;
 
-	if (pdev->dev.of_node) {
-		pdata->sda_pin = sda_pin;
-		pdata->scl_pin = scl_pin;
-		of_i2c_gpio_get_props(pdev->dev.of_node, pdata);
+	if (np) {
+		of_i2c_gpio_get_props(np, pdata);
 	} else {
-		memcpy(pdata, dev_get_platdata(&pdev->dev), sizeof(*pdata));
+		/*
+		 * If all platform data settings are zero it is OK
+		 * to not provide any platform data from the board.
+		 */
+		if (dev_get_platdata(dev))
+			memcpy(pdata, dev_get_platdata(dev), sizeof(*pdata));
 	}
 
-	if (pdata->sda_is_open_drain) {
-		gpio_direction_output(pdata->sda_pin, 1);
-		bit_data->setsda = i2c_gpio_setsda_val;
-	} else {
-		gpio_direction_input(pdata->sda_pin);
-		bit_data->setsda = i2c_gpio_setsda_dir;
-	}
+	/*
+	 * First get the GPIO pins; if it fails, we'll defer the probe.
+	 * If the SDA line is marked from platform data or device tree as
+	 * "open drain" it means something outside of our control is making
+	 * this line being handled as open drain, and we should just handle
+	 * it as any other output. Else we enforce open drain as this is
+	 * required for an I2C bus.
+	 */
+	if (pdata->sda_is_open_drain)
+		gflags = GPIOD_OUT_HIGH;
+	else
+		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
+	priv->sda = i2c_gpio_get_desc(dev, "sda", 0, gflags);
+	if (IS_ERR(priv->sda))
+		return PTR_ERR(priv->sda);
+
+	/*
+	 * If the SCL line is marked from platform data or device tree as
+	 * "open drain" it means something outside of our control is making
+	 * this line being handled as open drain, and we should just handle
+	 * it as any other output. Else we enforce open drain as this is
+	 * required for an I2C bus.
+	 */
+	if (pdata->scl_is_open_drain)
+		gflags = GPIOD_OUT_LOW;
+	else
+		gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
+	priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
+	if (IS_ERR(priv->scl))
+		return PTR_ERR(priv->scl);
 
-	if (pdata->scl_is_open_drain || pdata->scl_is_output_only) {
-		gpio_direction_output(pdata->scl_pin, 1);
-		bit_data->setscl = i2c_gpio_setscl_val;
-	} else {
-		gpio_direction_input(pdata->scl_pin);
-		bit_data->setscl = i2c_gpio_setscl_dir;
-	}
+	bit_data->setsda = i2c_gpio_setsda_val;
+	bit_data->setscl = i2c_gpio_setscl_val;
 
 	if (!pdata->scl_is_output_only)
 		bit_data->getscl = i2c_gpio_getscl;
@@ -207,18 +198,18 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	else
 		bit_data->timeout = HZ / 10;		/* 100 ms */
 
-	bit_data->data = pdata;
+	bit_data->data = priv;
 
 	adap->owner = THIS_MODULE;
-	if (pdev->dev.of_node)
-		strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
+	if (np)
+		strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
 	else
 		snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
 
 	adap->algo_data = bit_data;
 	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
-	adap->dev.parent = &pdev->dev;
-	adap->dev.of_node = pdev->dev.of_node;
+	adap->dev.parent = dev;
+	adap->dev.of_node = np;
 
 	adap->nr = pdev->id;
 	ret = i2c_bit_add_numbered_bus(adap);
@@ -227,8 +218,13 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
-	dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
-		 pdata->sda_pin, pdata->scl_pin,
+	/*
+	 * FIXME: using global GPIO numbers is not helpful. If/when we
+	 * get accessors to get the actual name of the GPIO line,
+	 * from the descriptor, then provide that instead.
+	 */
+	dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
+		 desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
 		 pdata->scl_is_output_only
 		 ? ", no clock stretching" : "");