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" : "");