Re: [PATCH v3 RESEND] media: i2c: Add OV05C10 camera sensor driver

["Nirujogi, Pratap" <pnirujog@amd.com>]

Hi Mehdi, Sakari, Laurent,

On 6/24/2025 7:27 AM, Mehdi Djait wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
> Hi Laurent, Hi Sakari,
> 
> On Tue, Jun 24, 2025 at 01:27:45PM +0300, Laurent Pinchart wrote:
>> On Tue, Jun 24, 2025 at 10:20:34AM +0000, Sakari Ailus wrote:
>>> On Tue, Jun 24, 2025 at 10:19:35AM +0000, Sakari Ailus wrote:
>>>> On Tue, Jun 24, 2025 at 10:35:18AM +0200, Mehdi Djait wrote:
>>>>> On Tue, Jun 24, 2025 at 01:05:03AM +0300, Laurent Pinchart wrote:
>>>>>> On Mon, Jun 23, 2025 at 05:51:48PM -0400, Nirujogi, Pratap wrote:
>>>>>>> On 6/16/2025 6:49 PM, Nirujogi, Pratap wrote:
>>>>>>>>>> +static int ov05c10_probe(struct i2c_client *client)
>>>>>>>>>> +{
>>>>>>>>>> +     struct ov05c10 *ov05c10;
>>>>>>>>>> +     u32 clkfreq;
>>>>>>>>>> +     int ret;
>>>>>>>>>> +
>>>>>>>>>> +     ov05c10 = devm_kzalloc(&client->dev, sizeof(*ov05c10),
>>>>>>>>>> GFP_KERNEL);
>>>>>>>>>> +     if (!ov05c10)
>>>>>>>>>> +             return -ENOMEM;
>>>>>>>>>> +
>>>>>>>>>> +     struct fwnode_handle *fwnode = dev_fwnode(&client->dev);
>>>>>>>>>> +
>>>>>>>>>> +     ret = fwnode_property_read_u32(fwnode, "clock-frequency",
>>>>>>>>>> &clkfreq);
>>>>>>>>>> +     if (ret)
>>>>>>>>>> +             return  dev_err_probe(&client->dev, -EINVAL,
>>>>>>>>>> +                                   "fail to get clock freq\n");
>>>>>>>>>
>>>>>>>>> Let's try to land
>>>>>>>>> https://lore.kernel.org/linux-media/20250521104115.176950-1-
>>>>>>>>> mehdi.djait@linux.intel.com/
>>>>>>>>> and replace the code above with devm_v4l2_sensor_clk_get().
>>>>>>>>>
>>>>>>>> Ok, we will verify on our side.
>>>>>>>
>>>>>>> We tried using devm_v4l2_sensor_clk_get() and found its required to add
>>>>>>> support for software_node to make it work with this driver.
>>>>>>
>>>>>> Why is that ?
>>>>>>
>>>>>>> Please refer
>>>>>>> the changes below and let us know if these should be submitted as a
>>>>>>> separate patch.
>>>>>
>>>>> The helper is still not merged, so no patch is required.
>>>>>
>>>>> I will see if a change is needed from the helper side or the OV05C10 side.
>>>>
>>>> I wonder if there's a better way to figure out if you're running on a DT or
>>>> ACPI based system than getting the device's parents and checking which one
>>>> you find first, DT or ACPI. I think that should work for now at least.
>>>
>>> Or, rather, checking for non-OF node here would probably work the best. I
>>> wouldn't expect these to be software node based on DT systems ever.
>>
>> Until it happens :-) And we'll handle it then.
> 
> So we have the following:
> 
> - The problem with this driver is due to lack of proper ACPI
>    description. HW is already shipping and AMD will work on better ACPI
>    description for future models. See [1]
> 
Thanks Mehdi for clarifying and providing the reference from the 
associated x86/platform driver patch.

yes, thats true we have to add software_nodes to mitigate the issue 
caused by incomplete description of camera device in ACPI tables.

For future models we are working on a plan to address this issue 
following the MIPI DisCo Imaging Spec suggested by Sakari to properly 
describe the camera device in ACPI. Please see [A]

Once again thanks everyone for the support!

[A] 
https://lore.kernel.org/lkml/2a9ba94e-7985-4ba9-88c6-45b8cf4d001f@amd.com/

> - software_node can also be used on DT systems
> 
> [1] https://lore.kernel.org/lkml/0d801367-da24-4596-83d9-08ccd89ca670@redhat.com/
> 
> Now going back to the helper. If we want to support this case:
> 
> Approach 1: software_node || acpi
> 
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -682,16 +682,17 @@ struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id)
>          const char *clk_id __free(kfree) = NULL;
>          struct clk_hw *clk_hw;
>          struct clk *clk;
> -       bool acpi_node;
> +       bool acpi_sw_node;
>          u32 rate;
>          int ret;
> 
>          clk = devm_clk_get_optional(dev, id);
>          ret = device_property_read_u32(dev, "clock-frequency", &rate);
> -       acpi_node = is_acpi_node(dev_fwnode(dev));
> +       acpi_sw_node = is_acpi_node(dev_fwnode(dev)) ||
> +                      is_software_node(dev_fwnode(dev));
> 
>          if (clk) {
> -               if (!ret && acpi_node) {
> +               if (!ret && acpi_sw_node) {
>                          ret = clk_set_rate(clk, rate);
>                          if (ret) {
>                                  dev_err(dev, "Failed to set clock rate: %u\n",
> @@ -705,7 +706,7 @@ struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id)
>          if (ret)
>                  return ERR_PTR(ret);
> 
> -       if (!IS_ENABLED(CONFIG_COMMON_CLK) || !acpi_node)
> +       if (!IS_ENABLED(CONFIG_COMMON_CLK) || !acpi_sw_node)
>                  return ERR_PTR(-ENOENT);
> 
>          if (!id) {
> 
> 
> Approach 2: of_node
> 
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -682,16 +682,16 @@ struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id)
>          const char *clk_id __free(kfree) = NULL;
>          struct clk_hw *clk_hw;
>          struct clk *clk;
> -       bool acpi_node;
> +       bool of_node;
>          u32 rate;
>          int ret;
> 
>          clk = devm_clk_get_optional(dev, id);
>          ret = device_property_read_u32(dev, "clock-frequency", &rate);
> -       acpi_node = is_acpi_node(dev_fwnode(dev));
> +       of_node = is_of_node(dev_fwnode(dev));
> 
>          if (clk) {
> -               if (!ret && acpi_node) {
> +               if (!ret && !of_node) {
>                          ret = clk_set_rate(clk, rate);
>                          if (ret) {
>                                  dev_err(dev, "Failed to set clock rate: %u\n",
> @@ -705,7 +705,7 @@ struct clk *devm_v4l2_sensor_clk_get(struct device *dev, const char *id)
>          if (ret)
>                  return ERR_PTR(ret);
> 
> -       if (!IS_ENABLED(CONFIG_COMMON_CLK) || !acpi_node)
> +       if (!IS_ENABLED(CONFIG_COMMON_CLK) || of_node)
>                  return ERR_PTR(-ENOENT);
> 
>          if (!id) {
> 
Thanks for proposing "approach 2 using !swnode", I verified and confirm 
it works at my end.

Thanks,
Pratap
> 
> --
> Kind Regards
> Mehdi Djait