| Message ID | b80d65600641e6dcf00da53ae797f4a40a80e2d0.1716976062.git.geert+renesas@glider.be |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] regulator: gpio: Correct default GPIO state to LOW | expand |
On Wed, May 29, 2024 at 11:49:51AM +0200, Geert Uytterhoeven wrote: > According to the GPIO regulator DT bindings[1], the default GPIO state > is LOW. However, the driver defaults to HIGH. > Before the conversion to descriptors in commit d6cd33ad71029a3f > ("regulator: gpio: Convert to use descriptors"), the default state used > by the driver was rather ill-defined, too: That was 4 years ago... > I have no idea if this has any impact. > I guess most/all DTS files have proper gpios-states properties? That seems optimistic, and a grep in mainline shows some users but not really as many as I'd intuitively expect. > - /* Default to high per specification */ > + /* Default to low per specification */ > if (ret) > - config->gflags[i] = GPIOD_OUT_HIGH; > + config->gflags[i] = GPIOD_OUT_LOW; > else The risk here is that we start glitching the power where previously we didn't. This does make me nervous.
Hi Mark, On Wed, May 29, 2024 at 3:15 PM Mark Brown <broonie@kernel.org> wrote: > On Wed, May 29, 2024 at 11:49:51AM +0200, Geert Uytterhoeven wrote: > > According to the GPIO regulator DT bindings[1], the default GPIO state > > is LOW. However, the driver defaults to HIGH. > > > Before the conversion to descriptors in commit d6cd33ad71029a3f > > ("regulator: gpio: Convert to use descriptors"), the default state used > > by the driver was rather ill-defined, too: > > That was 4 years ago... > > > I have no idea if this has any impact. > > I guess most/all DTS files have proper gpios-states properties? > > That seems optimistic, and a grep in mainline shows some users but not > really as many as I'd intuitively expect. > > > - /* Default to high per specification */ > > + /* Default to low per specification */ > > if (ret) > > - config->gflags[i] = GPIOD_OUT_HIGH; > > + config->gflags[i] = GPIOD_OUT_LOW; > > else > > The risk here is that we start glitching the power where previously we > didn't. This does make me nervous. /me too The alternative is to change the GPIO regulator DT bindings document to match the code... Gr{oetje,eeting}s, Geert
On Wed, May 29, 2024 at 03:19:04PM +0200, Geert Uytterhoeven wrote: > On Wed, May 29, 2024 at 3:15 PM Mark Brown <broonie@kernel.org> wrote: > > The risk here is that we start glitching the power where previously we > > didn't. This does make me nervous. > /me too > The alternative is to change the GPIO regulator DT bindings document > to match the code... Yup, that makes me feel a lot safer than changing the code.
diff --git a/drivers/regulator/gpio-regulator.c b/drivers/regulator/gpio-regulator.c index 65927fa2ef161cda..5dfed8bae0c4cfdc 100644 --- a/drivers/regulator/gpio-regulator.c +++ b/drivers/regulator/gpio-regulator.c @@ -176,9 +176,9 @@ of_get_gpio_regulator_config(struct device *dev, struct device_node *np, ret = of_property_read_u32_index(np, "gpios-states", i, &val); - /* Default to high per specification */ + /* Default to low per specification */ if (ret) - config->gflags[i] = GPIOD_OUT_HIGH; + config->gflags[i] = GPIOD_OUT_LOW; else config->gflags[i] = val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
According to the GPIO regulator DT bindings[1], the default GPIO state is LOW. However, the driver defaults to HIGH. Before the conversion to descriptors in commit d6cd33ad71029a3f ("regulator: gpio: Convert to use descriptors"), the default state used by the driver was rather ill-defined, too: - If the "gpio-states" property was missing or empty, the default was low, matching the bindings. - If the "gpio-states" property was present, the default for missing entries was the value of the last present entry. Fix this by making the driver adhere to the DT bindings, i.e. default to LOW. [1] Documentation/devicetree/bindings/regulator/gpio-regulator.yaml Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Linus Walleij <linus.walleij@linaro.org> --- I have no idea if this has any impact. I guess most/all DTS files have proper gpios-states properties? v2: - Add Acked-by. --- drivers/regulator/gpio-regulator.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)