diff mbox series

[7/7] i2c: gpio: Add support for named gpios in DT

Message ID 20170917093906.16325-8-linus.walleij@linaro.org
State Superseded
Headers show
Series I2C GPIO to use gpiolibs open drain | expand

Commit Message

Linus Walleij Sept. 17, 2017, 9:39 a.m. UTC 
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>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
This is pretty much a rewrite of Geerts patch on top of
my own changes to support descriptors.
---
 drivers/i2c/busses/i2c-gpio.c | 59 +++++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 16 deletions(-)

Comments

Geert Uytterhoeven Sept. 18, 2017, 9:26 a.m. UTC | #1 
On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> 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

get

> pointer.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Geert Uytterhoeven Sept. 18, 2017, 9:58 a.m. UTC | #2 
Hi Linus,

On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> 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>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> This is pretty much a rewrite of Geerts patch on top of
> my own changes to support descriptors.
> ---
>  drivers/i2c/busses/i2c-gpio.c | 59 +++++++++++++++++++++++++++++++------------
>  1 file changed, 43 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> index beb5ce523684..2738b851f470 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;

[...]

> +       if (ret != -EPROBE_DEFER)
> +               dev_err(dev, "error trying to get descriptor: %ld\n", ret);

warning: format '%ld' expects argument of type 'long int', but
argument 3 has type 'int' [-Wformat=]

%d (0day busy?)

> +
> +       return retdesc;
> +}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Linus Walleij Sept. 18, 2017, 7:09 p.m. UTC | #3 
On Mon, Sep 18, 2017 at 11:58 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:

>> +       if (ret != -EPROBE_DEFER)
>> +               dev_err(dev, "error trying to get descriptor: %ld\n", ret);
>
> warning: format '%ld' expects argument of type 'long int', but
> argument 3 has type 'int' [-Wformat=]
>
> %d (0day busy?)

Bah haven't pushed it to the 0day builders yet.
I'll do that tonight so I can drown in the build errors.
:-D

Fixing it.

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index beb5ce523684..2738b851f470 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: %ld\n", ret);
+
+	return retdesc;
+}
+
 static int i2c_gpio_probe(struct platform_device *pdev)
 {
 	struct i2c_gpio_private_data *priv;
@@ -125,14 +161,10 @@  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
@@ -144,14 +176,9 @@  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;