Re: [PATCH V3 27/29] PCI: OF: Add of_pci_get_reset_gpio() to parse reset-gpios from DT

[Rob Herring <robh@kernel.org>]

On Mon, May 13, 2019 at 11:37:42PM +0530, Manikanta Maddireddy wrote:
> This new helper function could be used by host drivers to get the reset
> GPIO descriptor. If the property isn't assigned, it will return NULL to
> the caller.
> 
> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
> ---
> V3: New patch to add helper function to parse "reset-gpios"
> 
>  drivers/pci/of.c       | 18 ++++++++++++++++++
>  include/linux/of_pci.h | 10 ++++++++++
>  2 files changed, 28 insertions(+)
> 
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index 9454c90980c9..2a0282115ff0 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -6,6 +6,7 @@
>   */
>  #define pr_fmt(fmt)	"PCI: OF: " fmt
>  
> +#include <linux/gpio/consumer.h>
>  #include <linux/irqdomain.h>
>  #include <linux/kernel.h>
>  #include <linux/pci.h>
> @@ -224,6 +225,23 @@ int of_pci_get_max_link_speed(struct device_node *node)
>  }
>  EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed);
>  
> +/**
> + * of_pci_get_reset_gpio() - Get PCI reset gpio descriptor.
> + *
> + * @node: device node
> + *
> + * Returns PCI reset gpio descriptor from DT, or an ERR_PTR() if the
> + * required property is invalid.
> + */
> +struct gpio_desc *of_pci_get_reset_gpio(struct device *dev,
> +					struct device_node *node,
> +					int dflags, char *label)
> +{
> +	return devm_gpiod_get_from_of_node(dev, node, "reset-gpios", 0, dflags,
> +					   label);
> +}

There's nothing PCI specific about this and 'reset-gpios' is pretty 
widely used. Either we should have this somewhere common or perhaps not 
worth a wrapper to save 1 parameter.

Also, I believe you can pass just 'reset' so the deprecated form 
'reset-gpio' can also be supported. 

Rob