| Message ID | 20240228-mbly-gpio-v2-25-3ba757474006@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Rework Nomadik GPIO to add Mobileye EyeQ5 support | expand |
On Wed, Feb 28, 2024 at 12:28 PM Théo Lebrun <theo.lebrun@bootlin.com> wrote: > Fetch a reference to the optional shared reset control and deassert it > if it exists. > > Optional because not all platforms that use this driver have a reset > attached to the reset block. Shared because some platforms that use the > reset (at least Mobileye EyeQ5) share the reset across banks. > > Do not keep a reference to the reset control as it is not needed > afterwards; the driver does not handle suspend, does not use runtime > PM, does not register a remove callback and does not support unbinding > from sysfs (made explicit with suppress_bind_attrs). > > The operation is done in nmk_gpio_populate_chip(). This function is > called by either gpio-nomadik or pinctrl-nomadik, whoever comes first. > This is here for historic reasons and could probably be removed now; it > seems gpio-ranges enforces the ordering to be pinctrl-first. It is not > the topic of the present patch however. > > Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> Patch applied! Yours, Linus Walleij
diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c index 6adb3c4417d3..c9fd6631e0aa 100644 --- a/drivers/gpio/gpio-nomadik.c +++ b/drivers/gpio/gpio-nomadik.c @@ -509,11 +509,13 @@ struct nmk_gpio_chip *nmk_gpio_populate_chip(struct device_node *np, { struct nmk_gpio_chip *nmk_chip; struct platform_device *gpio_pdev; + struct reset_control *reset; struct device *gpio_dev; struct gpio_chip *chip; struct clk *clk; void __iomem *base; u32 id, ngpio; + int ret; gpio_dev = bus_find_device_by_of_node(&platform_bus_type, np); if (!gpio_dev) { @@ -572,6 +574,24 @@ struct nmk_gpio_chip *nmk_gpio_populate_chip(struct device_node *np, clk_prepare(clk); nmk_chip->clk = clk; + reset = devm_reset_control_get_optional_shared(gpio_dev, NULL); + if (IS_ERR(reset)) { + dev_err(&pdev->dev, "failed getting reset control: %ld\n", + PTR_ERR(reset)); + return ERR_CAST(reset); + } + + /* + * Reset might be shared and asserts/deasserts calls are unbalanced. We + * only support sharing this reset with other gpio-nomadik devices that + * use this reset to ensure deassertion at probe. + */ + ret = reset_control_deassert(reset); + if (ret) { + dev_err(&pdev->dev, "failed reset deassert: %d\n", ret); + return ERR_PTR(ret); + } + #ifdef CONFIG_PINCTRL_NOMADIK BUG_ON(nmk_chip->bank >= ARRAY_SIZE(nmk_gpio_chips)); nmk_gpio_chips[id] = nmk_chip; @@ -690,6 +710,7 @@ static struct platform_driver nmk_gpio_driver = { .driver = { .name = "nomadik-gpio", .of_match_table = nmk_gpio_match, + .suppress_bind_attrs = true, }, .probe = nmk_gpio_probe, };
Fetch a reference to the optional shared reset control and deassert it if it exists. Optional because not all platforms that use this driver have a reset attached to the reset block. Shared because some platforms that use the reset (at least Mobileye EyeQ5) share the reset across banks. Do not keep a reference to the reset control as it is not needed afterwards; the driver does not handle suspend, does not use runtime PM, does not register a remove callback and does not support unbinding from sysfs (made explicit with suppress_bind_attrs). The operation is done in nmk_gpio_populate_chip(). This function is called by either gpio-nomadik or pinctrl-nomadik, whoever comes first. This is here for historic reasons and could probably be removed now; it seems gpio-ranges enforces the ordering to be pinctrl-first. It is not the topic of the present patch however. Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> --- drivers/gpio/gpio-nomadik.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)