[U-Boot] [PATCH v3 2/2] gpio: dwapb_gpio: Add reset ctrl to driver

[Marek Vasut]

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 <ley.foon.tan at intel.com>
> 
> ---
> 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