[PATCH v3] drm/amdgpu: add return result for amdgpu_i2c_{get/put}_byte

[Christian König]

Am 24.04.24 um 11:36 schrieb Bob Zhou:
> After amdgpu_i2c_get_byte fail, amdgpu_i2c_put_byte shouldn't be
> conducted to put wrong value.
> So return and check the i2c transfer result.
>
> Signed-off-by: Bob Zhou <bob.zhou at amd.com>
> Suggested-by: Christian König <christian.koenig at amd.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c | 47 +++++++++++++++----------
>   1 file changed, 28 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> index 82608df43396..e0f3bff335c4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c
> @@ -280,7 +280,7 @@ amdgpu_i2c_lookup(struct amdgpu_device *adev,
>   	return NULL;
>   }
>   
> -static void amdgpu_i2c_get_byte(struct amdgpu_i2c_chan *i2c_bus,
> +static int amdgpu_i2c_get_byte(struct amdgpu_i2c_chan *i2c_bus,
>   				 u8 slave_addr,
>   				 u8 addr,
>   				 u8 *val)
> @@ -305,16 +305,18 @@ static void amdgpu_i2c_get_byte(struct amdgpu_i2c_chan *i2c_bus,
>   	out_buf[0] = addr;
>   	out_buf[1] = 0;
>   
> -	if (i2c_transfer(&i2c_bus->adapter, msgs, 2) == 2) {
> -		*val = in_buf[0];
> -		DRM_DEBUG("val = 0x%02x\n", *val);
> -	} else {
> -		DRM_DEBUG("i2c 0x%02x 0x%02x read failed\n",
> -			  addr, *val);
> +	if (i2c_transfer(&i2c_bus->adapter, msgs, 2) != 2) {
> +		DRM_DEBUG("i2c 0x%02x read failed\n", addr);
> +		return -EIO;
>   	}
> +
> +	*val = in_buf[0];
> +	DRM_DEBUG("val = 0x%02x\n", *val);
> +
> +	return 0;
>   }
>   
> -static void amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus,
> +static int amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus,
>   				 u8 slave_addr,
>   				 u8 addr,
>   				 u8 val)
> @@ -330,9 +332,12 @@ static void amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus,
>   	out_buf[0] = addr;
>   	out_buf[1] = val;
>   
> -	if (i2c_transfer(&i2c_bus->adapter, &msg, 1) != 1)
> -		DRM_DEBUG("i2c 0x%02x 0x%02x write failed\n",
> -			  addr, val);
> +	if (i2c_transfer(&i2c_bus->adapter, &msg, 1) != 1) {
> +		DRM_DEBUG("i2c 0x%02x 0x%02x write failed\n", addr, val);
> +		return -EIO;
> +	}
> +
> +	return 0;
>   }
>   
>   /* ddc router switching */
> @@ -347,16 +352,18 @@ amdgpu_i2c_router_select_ddc_port(const struct amdgpu_connector *amdgpu_connecto
>   	if (!amdgpu_connector->router_bus)
>   		return;
>   
> -	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
> +	if (amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
>   			    amdgpu_connector->router.i2c_addr,
> -			    0x3, &val);
> +			    0x3, &val))
> +		return;
>   	val &= ~amdgpu_connector->router.ddc_mux_control_pin;
>   	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
>   			    amdgpu_connector->router.i2c_addr,
>   			    0x3, val);
> -	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
> +	if (amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
>   			    amdgpu_connector->router.i2c_addr,
> -			    0x1, &val);
> +			    0x1, &val))
> +		return;
>   	val &= ~amdgpu_connector->router.ddc_mux_control_pin;
>   	val |= amdgpu_connector->router.ddc_mux_state;
>   	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
> @@ -376,16 +383,18 @@ amdgpu_i2c_router_select_cd_port(const struct amdgpu_connector *amdgpu_connector
>   	if (!amdgpu_connector->router_bus)
>   		return;
>   
> -	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
> +	if (amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
>   			    amdgpu_connector->router.i2c_addr,
> -			    0x3, &val);
> +			    0x3, &val))
> +		return;
>   	val &= ~amdgpu_connector->router.cd_mux_control_pin;
>   	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
>   			    amdgpu_connector->router.i2c_addr,
>   			    0x3, val);
> -	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
> +	if (amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
>   			    amdgpu_connector->router.i2c_addr,
> -			    0x1, &val);
> +			    0x1, &val))
> +		return;
>   	val &= ~amdgpu_connector->router.cd_mux_control_pin;
>   	val |= amdgpu_connector->router.cd_mux_state;
>   	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,