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[PATCH RESEND v1 4/8] drm/stm: ltdc: implement bus clock

Posted by Raphael Gallais-Pou 2 years ago

From: Yannick Fertre <yannick.fertre@foss.st.com>

The latest hardware version of the LTDC presents the addition of a bus
clock, which contains the global configuration registers and the interrupt
register.

Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
---
 drivers/gpu/drm/stm/ltdc.c | 8 ++++++++
 drivers/gpu/drm/stm/ltdc.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 5576fdae4962..67064f47a4cb 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -1896,6 +1896,8 @@ void ltdc_suspend(struct drm_device *ddev)
 
 	DRM_DEBUG_DRIVER("\n");
 	clk_disable_unprepare(ldev->pixel_clk);
+	if (ldev->bus_clk)
+		clk_disable_unprepare(ldev->bus_clk);
 }
 
 int ltdc_resume(struct drm_device *ddev)
@@ -1910,6 +1912,12 @@ int ltdc_resume(struct drm_device *ddev)
 		DRM_ERROR("failed to enable pixel clock (%d)\n", ret);
 		return ret;
 	}
+	if (ldev->bus_clk) {
+		if (clk_prepare_enable(ldev->bus_clk)) {
+			DRM_ERROR("Unable to prepare bus clock\n");
+			return -ENODEV;
+		}
+	}
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index 9d488043ffdb..155d8e4a7c6b 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -44,6 +44,7 @@ struct ltdc_device {
 	void __iomem *regs;
 	struct regmap *regmap;
 	struct clk *pixel_clk;	/* lcd pixel clock */
+	struct clk *bus_clk;	/* bus clock */
 	struct mutex err_lock;	/* protecting error_status */
 	struct ltdc_caps caps;
 	u32 irq_status;
-- 
2.25.1

Re: [PATCH RESEND v1 4/8] drm/stm: ltdc: implement bus clock

Posted by Dmitry Baryshkov 2 years ago

On Thu, 21 Dec 2023 at 14:45, Raphael Gallais-Pou
<raphael.gallais-pou@foss.st.com> wrote:
>
> From: Yannick Fertre <yannick.fertre@foss.st.com>
>
> The latest hardware version of the LTDC presents the addition of a bus
> clock, which contains the global configuration registers and the interrupt
> register.
>
> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> ---
>  drivers/gpu/drm/stm/ltdc.c | 8 ++++++++
>  drivers/gpu/drm/stm/ltdc.h | 1 +
>  2 files changed, 9 insertions(+)

I might be missing something, but I don't see this clock being set
(compare this patch to the patch 5/8)

>
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 5576fdae4962..67064f47a4cb 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -1896,6 +1896,8 @@ void ltdc_suspend(struct drm_device *ddev)
>
>         DRM_DEBUG_DRIVER("\n");
>         clk_disable_unprepare(ldev->pixel_clk);
> +       if (ldev->bus_clk)
> +               clk_disable_unprepare(ldev->bus_clk);
>  }
>
>  int ltdc_resume(struct drm_device *ddev)
> @@ -1910,6 +1912,12 @@ int ltdc_resume(struct drm_device *ddev)
>                 DRM_ERROR("failed to enable pixel clock (%d)\n", ret);
>                 return ret;
>         }
> +       if (ldev->bus_clk) {
> +               if (clk_prepare_enable(ldev->bus_clk)) {
> +                       DRM_ERROR("Unable to prepare bus clock\n");
> +                       return -ENODEV;
> +               }
> +       }
>
>         return 0;
>  }
> diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
> index 9d488043ffdb..155d8e4a7c6b 100644
> --- a/drivers/gpu/drm/stm/ltdc.h
> +++ b/drivers/gpu/drm/stm/ltdc.h
> @@ -44,6 +44,7 @@ struct ltdc_device {
>         void __iomem *regs;
>         struct regmap *regmap;
>         struct clk *pixel_clk;  /* lcd pixel clock */
> +       struct clk *bus_clk;    /* bus clock */
>         struct mutex err_lock;  /* protecting error_status */
>         struct ltdc_caps caps;
>         u32 irq_status;
> --
> 2.25.1
>


-- 
With best wishes
Dmitry

Re: [PATCH RESEND v1 4/8] drm/stm: ltdc: implement bus clock

Posted by Raphael Gallais-Pou 1 year, 11 months ago

On 12/21/23 14:17, Dmitry Baryshkov wrote:
> On Thu, 21 Dec 2023 at 14:45, Raphael Gallais-Pou
> <raphael.gallais-pou@foss.st.com> wrote:
>> From: Yannick Fertre <yannick.fertre@foss.st.com>
>>
>> The latest hardware version of the LTDC presents the addition of a bus
>> clock, which contains the global configuration registers and the interrupt
>> register.
>>
>> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
>> ---
>>  drivers/gpu/drm/stm/ltdc.c | 8 ++++++++
>>  drivers/gpu/drm/stm/ltdc.h | 1 +
>>  2 files changed, 9 insertions(+)
> I might be missing something, but I don't see this clock being set
> (compare this patch to the patch 5/8)


Hi Dmitry,

This patch needs rework. I'll drop it for now and send it back later when it is
more mature.

Regards,

Raphaël

>
>> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
>> index 5576fdae4962..67064f47a4cb 100644
>> --- a/drivers/gpu/drm/stm/ltdc.c
>> +++ b/drivers/gpu/drm/stm/ltdc.c
>> @@ -1896,6 +1896,8 @@ void ltdc_suspend(struct drm_device *ddev)
>>
>>         DRM_DEBUG_DRIVER("\n");
>>         clk_disable_unprepare(ldev->pixel_clk);
>> +       if (ldev->bus_clk)
>> +               clk_disable_unprepare(ldev->bus_clk);
>>  }
>>
>>  int ltdc_resume(struct drm_device *ddev)
>> @@ -1910,6 +1912,12 @@ int ltdc_resume(struct drm_device *ddev)
>>                 DRM_ERROR("failed to enable pixel clock (%d)\n", ret);
>>                 return ret;
>>         }
>> +       if (ldev->bus_clk) {
>> +               if (clk_prepare_enable(ldev->bus_clk)) {
>> +                       DRM_ERROR("Unable to prepare bus clock\n");
>> +                       return -ENODEV;
>> +               }
>> +       }
>>
>>         return 0;
>>  }
>> diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
>> index 9d488043ffdb..155d8e4a7c6b 100644
>> --- a/drivers/gpu/drm/stm/ltdc.h
>> +++ b/drivers/gpu/drm/stm/ltdc.h
>> @@ -44,6 +44,7 @@ struct ltdc_device {
>>         void __iomem *regs;
>>         struct regmap *regmap;
>>         struct clk *pixel_clk;  /* lcd pixel clock */
>> +       struct clk *bus_clk;    /* bus clock */
>>         struct mutex err_lock;  /* protecting error_status */
>>         struct ltdc_caps caps;
>>         u32 irq_status;
>> --
>> 2.25.1
>>
>