On 08/28/2018 06:07 PM, Ley Foon Tan wrote:
> Add code to reset all reset signals as in gpio DT node. A reset property
> is an optional feature, so only print out a warning and do not fail if a
> reset property is not present.
>
> If a reset property is discovered, then use it to deassert, thus
> bringing the IP out of reset.
>
> Signed-off-by: Ley Foon Tan <[email protected]>
>
> ---
> v3:
> - Add .remove function.
> - Add error handling when return non-zero from reset_get_bulk().
>
> v2:
> - Move reset to probe() function.
> ---
> drivers/gpio/dwapb_gpio.c | 42 ++++++++++++++++++++++++++++++++++++++++--
> 1 files changed, 40 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/dwapb_gpio.c b/drivers/gpio/dwapb_gpio.c
> index 7cf2d47..6394fa9 100644
> --- a/drivers/gpio/dwapb_gpio.c
> +++ b/drivers/gpio/dwapb_gpio.c
> @@ -15,6 +15,7 @@
> #include <dm/lists.h>
> #include <dm/root.h>
> #include <errno.h>
> +#include <reset.h>
>
> DECLARE_GLOBAL_DATA_PTR;
>
> @@ -99,13 +100,42 @@ static const struct dm_gpio_ops gpio_dwapb_ops = {
> .get_function = dwapb_gpio_get_function,
> };
>
> +static int gpio_dwapb_reset(struct udevice *dev)
> +{
> + int ret;
> + struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
> +
> + ret = reset_get_bulk(dev, &priv->resets);
> + if (ret) {
> + dev_warn(dev, "Can't get reset: %d\n", ret);
> + /* Return 0 if error due to !CONFIG_DM_RESET and reset
> + * DT property is not present.
> + */
> + if (ret == -ENOENT || ret == -ENOTSUPP)
> + return 0;
> + else
> + return ret;
> + }
> +
> + ret = reset_deassert_bulk(&priv->resets);
> + if (ret) {
> + reset_release_bulk(&priv->resets);
> + dev_err(dev, "Failed to reset: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> static int gpio_dwapb_probe(struct udevice *dev)
> {
> struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
> struct gpio_dwapb_platdata *plat = dev->platdata;
>
> - if (!plat)
> - return 0;
> + if (!plat) {
> + /* Reset on parent device only */
> + return gpio_dwapb_reset(dev);
> + }
>
> priv->gpio_count = plat->pins;
> priv->bank_name = plat->name;
> @@ -166,6 +196,13 @@ err:
> return ret;
> }
>
> +static int gpio_dwapb_remove(struct udevice *dev)
> +{
> + struct gpio_dev_priv *priv = dev_get_uclass_priv(dev);
You might want to assert the reset too.
> + return reset_release_bulk(&priv->resets);
> +}
> +
> static const struct udevice_id gpio_dwapb_ids[] = {
> { .compatible = "snps,dw-apb-gpio" },
> { }
> @@ -178,4 +215,5 @@ U_BOOT_DRIVER(gpio_dwapb) = {
> .ops = &gpio_dwapb_ops,
> .bind = gpio_dwapb_bind,
> .probe = gpio_dwapb_probe,
> + .remove = gpio_dwapb_remove,
> };
>
--
Best regards,
Marek Vasut
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