linux-kernel - Re: [PATCH v8 2/4] pps: descriptor-based gpio, capture-clear addition

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Message-ID: <CA+gwMcfQ5cUZPmAJ6Uhb0KQsmwjtoSdRJVnAzk9mwy=-M19M2Q@mail.gmail.com>
Date:   Fri, 23 Nov 2018 08:46:28 +0100
From:   Philipp Zabel <philipp.zabel@...il.com>
To:     tom@...sec.com
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v8 2/4] pps: descriptor-based gpio, capture-clear addition

Hi Tom,

On Sat, Nov 17, 2018 at 2:07 PM Tom Burkart <tom@...sec.com> wrote:
>
> This patch changes the GPIO access for the pps-gpio driver from the
> integer based ABI to the descriptor based ABI.  It also adds the
> extraction of the device tree capture-clear option.

Is the capture-clear property documented in
Documentation/devicetree/bindings/pps/pps-gpio.txt?
If not, you should add a binding documentation patch.

> Signed-off-by: Tom Burkart <tom@...sec.com>
> ---
>  drivers/pps/clients/pps-gpio.c | 80 +++++++++++++++++++++---------------------
>  include/linux/pps-gpio.h       |  3 +-
>  2 files changed, 41 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
> index 333ad7d5b45b..d2fbc91dc8fc 100644
> --- a/drivers/pps/clients/pps-gpio.c
> +++ b/drivers/pps/clients/pps-gpio.c
> @@ -31,7 +31,7 @@
>  #include <linux/slab.h>
>  #include <linux/pps_kernel.h>
>  #include <linux/pps-gpio.h>
> -#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/list.h>
>  #include <linux/of_device.h>
>  #include <linux/of_gpio.h>
> @@ -41,9 +41,9 @@ struct pps_gpio_device_data {
>         int irq;                        /* IRQ used as PPS source */
>         struct pps_device *pps;         /* PPS source device */
>         struct pps_source_info info;    /* PPS source information */
> +       struct gpio_desc *gpio_pin;     /* GPIO port descriptors */
>         bool assert_falling_edge;
>         bool capture_clear;
> -       unsigned int gpio_pin;
>  };
>
>  /*
> @@ -61,18 +61,49 @@ static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
>
>         info = data;
>
> -       rising_edge = gpio_get_value(info->gpio_pin);
> +       rising_edge = gpiod_get_value(info->gpio_pin);
>         if ((rising_edge && !info->assert_falling_edge) ||
>                         (!rising_edge && info->assert_falling_edge))
>                 pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
>         else if (info->capture_clear &&
>                         ((rising_edge && info->assert_falling_edge) ||
> -                        (!rising_edge && !info->assert_falling_edge)))
> +                       (!rising_edge && !info->assert_falling_edge)))
>                 pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
>
>         return IRQ_HANDLED;
>  }
>
> +static int pps_gpio_setup(struct platform_device *pdev)
> +{
> +       struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
> +       const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
> +       struct device_node *np = pdev->dev.of_node;
> +       int ret;

Unused variable?

> +
> +       if (pdata) {
> +               data->gpio_pin = pdata->gpio_pin;
> +
> +               data->assert_falling_edge = pdata->assert_falling_edge;
> +               data->capture_clear = pdata->capture_clear;

This is just a matter of personal taste, so feel free to ignore:
I would keep the pdata branch in pps_gpio_probe and call this function
pps_gpio_dt_setup, to reduce indentation of the OF branch.

> +       } else {
> +               data->gpio_pin = devm_gpiod_get(&pdev->dev,
> +                       NULL,   /* request "gpios" */
> +                       GPIOD_IN);
> +               if (IS_ERR(data->gpio_pin)) {
> +                       dev_err(&pdev->dev,
> +                               "failed to request PPS GPIO\n");
> +                       return PTR_ERR(data->gpio_pin);
> +               }
> +
> +               if (of_get_property(np, "assert-falling-edge", NULL))
> +                       data->assert_falling_edge = true;
> +
> +               if (of_get_property(np, "capture-clear", NULL))
> +                       data->capture_clear = true;

Those two should use the of_property_read_bool wrapper.

> +       }
> +       return 0;
> +}
> +
>  static unsigned long
>  get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
>  {
> @@ -90,53 +121,23 @@ get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
>  static int pps_gpio_probe(struct platform_device *pdev)
>  {
>         struct pps_gpio_device_data *data;
> -       const char *gpio_label;
>         int ret;
>         int pps_default_params;
> -       const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
> -       struct device_node *np = pdev->dev.of_node;
>
>         /* allocate space for device info */
>         data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),

Could use sizeof(*data) here. Otherwise,

Reviewed-by: Philipp Zabel <philipp.zabel@...il.com>

regards
Philipp