Re: [PATCH 2/3] dm: button: add support for linux_code in button-gpio.c driver

[Quentin Schulz]

Hi Dzmitry,

On 1/11/23 11:19, Dzmitry Sankouski wrote:
Linux event code may be used in input devices, using buttons.
Signed-off-by: Dzmitry Sankouski <dsankou...@gmail.com>
---
  drivers/button/button-gpio.c   | 20 ++++++++++++++++++++
  drivers/button/button-uclass.c | 10 ++++++++++
  include/button.h               | 16 ++++++++++++++++
  3 files changed, 46 insertions(+)

diff --git a/drivers/button/button-gpio.c b/drivers/button/button-gpio.c
index dbb000622c..e6eff5c1da 100644
--- a/drivers/button/button-gpio.c
+++ b/drivers/button/button-gpio.c
@@ -13,6 +13,7 @@
  
  struct button_gpio_priv {
        struct gpio_desc gpio;
+       u32 linux_code;
  };
  
  static enum button_state_t button_gpio_get_state(struct udevice *dev)
@@ -29,10 +30,22 @@ static enum button_state_t button_gpio_get_state(struct 
udevice *dev)
        return ret ? BUTTON_ON : BUTTON_OFF;
  }
  
+static u32 button_gpio_get_code(struct udevice *dev)
+{
+       struct button_gpio_priv *priv = dev_get_priv(dev);
+       u32 code = priv->linux_code;
+
+       if (!code)
+               return 0;
+
+       return code;
+}
+
  static int button_gpio_probe(struct udevice *dev)
  {
        struct button_uc_plat *uc_plat = dev_get_uclass_plat(dev);
        struct button_gpio_priv *priv = dev_get_priv(dev);
+       u32 linux_code;
        int ret;
  
  	/* Ignore the top-level button node */
@@ -43,6 +56,12 @@ static int button_gpio_probe(struct udevice *dev)
        if (ret)
                return ret;
  
+	linux_code = dev_read_u32_default(dev, "linux,code", -ENODATA);
+       debug("linux code value: %d, ret: %d", linux_code, ret);
+       if (ret)
+               return ret;

ret is not modified here so it'll always pass even if it fails to parse 
dev_read_u32_default.

I believe dev_read_u32_default incorrectly requests an int as last 
argument while it's going to fill it with u32 data on success. 
dev_read_u8/u16 get this correctly so that might just be an oversight.

Please use dev_read_u32 instead:

ret = dev_read_u32(dev, "linux,code", &priv->linux_code);
debug("linux code value: %d, ret: %d", linux_code, ret);
return ret;

(no need to check the value of ret since it's the same as
if (ret)
    return ret;

return 0;
)

Cheers,
Quentin