[PATCH 19/23] gpio: nomadik: grab optional reset control and deassert it at probe

Théo Lebrun
2024-02-14T16:25:00Z

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
and does not register a remove callback.

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 | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/drivers/gpio/gpio-nomadik.c b/drivers/gpio/gpio-nomadik.c
index 21bb6d6363fc..b623c093b54d 100644
--- a/drivers/gpio/gpio-nomadik.c
+++ b/drivers/gpio/gpio-nomadik.c
@@ -513,12 +513,14 @@ 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 gpio_chip *chip;
struct resource *res;
struct clk *clk;
void __iomem *base;
uintptr_t flags;
u32 id, ngpio;
+ int ret;

gpio_pdev = of_find_device_by_node(np);
if (!gpio_pdev) {
@@ -576,6 +578,19 @@ 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_pdev->dev, NULL);
+ if (IS_ERR(reset)) {
+ dev_err(&pdev->dev, "failed getting reset control: %ld\n",
+ PTR_ERR(reset));
+ return ERR_CAST(reset);
+ }
+
+ 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;

--
2.43.1