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authorLinus Walleij <linus.walleij@linaro.org>2017-09-16 23:56:49 +0200
committerLinus Walleij <linus.walleij@linaro.org>2017-10-30 08:42:59 +0100
commit05c74778858d7d9907d607172fcc9646b70b6364 (patch)
treeebbbec1519344517a96ba562ca78c8496d59832a /drivers/i2c
parent7d29f509d2cfd807b2fccc643ac1f7066b9b1949 (diff)
downloadlinux-05c74778858d7d9907d607172fcc9646b70b6364.tar.bz2
i2c: gpio: Add support for named gpios in DT
This adds support for using the "sda" and "scl" GPIOs in device tree instead of anonymously using index 0 and 1 of the "gpios" property. We add a helper function to retrieve the GPIO descriptors and some explicit error handling since the probe may have to be deferred. At least this happened to me when moving to using named "sda" and "scl" lines (all of a sudden this started to probe before the GPIO driver) so we need to gracefully defer probe when we ge -ENOENT in the error pointer. Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-gpio.c59
1 files changed, 43 insertions, 16 deletions
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index a702e493275c..d80ea6ce91bb 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -82,6 +82,42 @@ 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;
@@ -124,14 +160,10 @@ static int i2c_gpio_probe(struct platform_device *pdev)
gflags = GPIOD_OUT_HIGH;
else
gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
- priv->sda = devm_gpiod_get_index(dev, NULL, 0, gflags);
- if (IS_ERR(priv->sda)) {
- ret = PTR_ERR(priv->sda);
- /* FIXME: hack in the old code, is this really necessary? */
- if (ret == -EINVAL)
- ret = -EPROBE_DEFER;
- return ret;
- }
+ 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
@@ -143,14 +175,9 @@ static int i2c_gpio_probe(struct platform_device *pdev)
gflags = GPIOD_OUT_LOW;
else
gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
- priv->scl = devm_gpiod_get_index(dev, NULL, 1, gflags);
- if (IS_ERR(priv->scl)) {
- ret = PTR_ERR(priv->scl);
- /* FIXME: hack in the old code, is this really necessary? */
- if (ret == -EINVAL)
- ret = -EPROBE_DEFER;
- return ret;
- }
+ priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
+ if (IS_ERR(priv->scl))
+ return PTR_ERR(priv->scl);
bit_data->setsda = i2c_gpio_setsda_val;
bit_data->setscl = i2c_gpio_setscl_val;