[PATCH] drm/stm: ltdc: use crtc_mode_fixup to update adjusted_mode clock

[PATCH] drm/stm: ltdc: use crtc_mode_fixup to update adjusted_mode clock

[Philippe Cornu]

There is a difference between the panel/bridge requested pixel clock
value and the real one due to the hw platform clock preciseness (pll,
dividers...). This patch updates the adjusted_mode clock value with
the real hw clock value so then attached encoder & connector can use
it for precise timing computations.

Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
---
 drivers/gpu/drm/stm/ltdc.c | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index b48589343ae1..90b3de516c91 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -428,12 +428,35 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc,
 	reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
 }
 
+static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
+				 const struct drm_display_mode *mode,
+				 struct drm_display_mode *adjusted_mode)
+{
+	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
+	int rate = mode->clock * 1000;
+
+	/*
+	 * TODO clk_round_rate() does not work yet. When ready, it can
+	 * be used instead of clk_set_rate() then clk_get_rate().
+	 */
+
+	clk_disable(ldev->pixel_clk);
+	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
+		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
+		return false;
+	}
+	clk_enable(ldev->pixel_clk);
+
+	adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
+
+	return true;
+}
+
 static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
 {
 	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
 	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
 	struct videomode vm;
-	int rate = mode->clock * 1000;
 	u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
 	u32 total_width, total_height;
 	u32 val;
@@ -456,15 +479,6 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
 	total_width = accum_act_w + vm.hfront_porch;
 	total_height = accum_act_h + vm.vfront_porch;
 
-	clk_disable(ldev->pixel_clk);
-
-	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
-		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
-		return;
-	}
-
-	clk_enable(ldev->pixel_clk);
-
 	/* Configures the HS, VS, DE and PC polarities. Default Active Low */
 	val = 0;
 
@@ -528,6 +542,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
 }
 
 static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
+	.mode_fixup = ltdc_crtc_mode_fixup,
 	.mode_set_nofb = ltdc_crtc_mode_set_nofb,
 	.atomic_flush = ltdc_crtc_atomic_flush,
 	.atomic_enable = ltdc_crtc_atomic_enable,
-- 
2.15.1

Re: [PATCH] drm/stm: ltdc: use crtc_mode_fixup to update adjusted_mode clock

[Yannick FERTRE]

On 01/25/2018 05:01 PM, Philippe Cornu wrote:
> There is a difference between the panel/bridge requested pixel clock
> value and the real one due to the hw platform clock preciseness (pll,
> dividers...). This patch updates the adjusted_mode clock value with
> the real hw clock value so then attached encoder & connector can use
> it for precise timing computations.
Reviewed-by: Yannick Fertré <yannick.fertre@st.com>
> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
> ---
>   drivers/gpu/drm/stm/ltdc.c | 35 +++++++++++++++++++++++++----------
>   1 file changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index b48589343ae1..90b3de516c91 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -428,12 +428,35 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc,
>   	reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
>   }
>   
> +static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
> +				 const struct drm_display_mode *mode,
> +				 struct drm_display_mode *adjusted_mode)
> +{
> +	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> +	int rate = mode->clock * 1000;
> +
> +	/*
> +	 * TODO clk_round_rate() does not work yet. When ready, it can
> +	 * be used instead of clk_set_rate() then clk_get_rate().
> +	 */
> +
> +	clk_disable(ldev->pixel_clk);
> +	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
> +		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> +		return false;
> +	}
> +	clk_enable(ldev->pixel_clk);
> +
> +	adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
> +
> +	return true;
> +}
> +
>   static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
>   {
>   	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
>   	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>   	struct videomode vm;
> -	int rate = mode->clock * 1000;
>   	u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
>   	u32 total_width, total_height;
>   	u32 val;
> @@ -456,15 +479,6 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
>   	total_width = accum_act_w + vm.hfront_porch;
>   	total_height = accum_act_h + vm.vfront_porch;
>   
> -	clk_disable(ldev->pixel_clk);
> -
> -	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
> -		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> -		return;
> -	}
> -
> -	clk_enable(ldev->pixel_clk);
> -
>   	/* Configures the HS, VS, DE and PC polarities. Default Active Low */
>   	val = 0;
>   
> @@ -528,6 +542,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
>   }
>   
>   static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
> +	.mode_fixup = ltdc_crtc_mode_fixup,
>   	.mode_set_nofb = ltdc_crtc_mode_set_nofb,
>   	.atomic_flush = ltdc_crtc_atomic_flush,
>   	.atomic_enable = ltdc_crtc_atomic_enable,

Re: [PATCH] drm/stm: ltdc: use crtc_mode_fixup to update adjusted_mode clock

[Benjamin Gaignard]

2018-01-29 10:46 GMT+01:00 Yannick FERTRE <yannick.fertre@st.com>:
> On 01/25/2018 05:01 PM, Philippe Cornu wrote:
>> There is a difference between the panel/bridge requested pixel clock
>> value and the real one due to the hw platform clock preciseness (pll,
>> dividers...). This patch updates the adjusted_mode clock value with
>> the real hw clock value so then attached encoder & connector can use
>> it for precise timing computations.
> Reviewed-by: Yannick Fertré <yannick.fertre@st.com>
>> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>

Applied on drm-misc-next.

Regards,
Benjamin

>> ---
>>   drivers/gpu/drm/stm/ltdc.c | 35 +++++++++++++++++++++++++----------
>>   1 file changed, 25 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
>> index b48589343ae1..90b3de516c91 100644
>> --- a/drivers/gpu/drm/stm/ltdc.c
>> +++ b/drivers/gpu/drm/stm/ltdc.c
>> @@ -428,12 +428,35 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc,
>>       reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
>>   }
>>
>> +static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
>> +                              const struct drm_display_mode *mode,
>> +                              struct drm_display_mode *adjusted_mode)
>> +{
>> +     struct ltdc_device *ldev = crtc_to_ltdc(crtc);
>> +     int rate = mode->clock * 1000;
>> +
>> +     /*
>> +      * TODO clk_round_rate() does not work yet. When ready, it can
>> +      * be used instead of clk_set_rate() then clk_get_rate().
>> +      */
>> +
>> +     clk_disable(ldev->pixel_clk);
>> +     if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
>> +             DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
>> +             return false;
>> +     }
>> +     clk_enable(ldev->pixel_clk);
>> +
>> +     adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
>> +
>> +     return true;
>> +}
>> +
>>   static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
>>   {
>>       struct ltdc_device *ldev = crtc_to_ltdc(crtc);
>>       struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>>       struct videomode vm;
>> -     int rate = mode->clock * 1000;
>>       u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
>>       u32 total_width, total_height;
>>       u32 val;
>> @@ -456,15 +479,6 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
>>       total_width = accum_act_w + vm.hfront_porch;
>>       total_height = accum_act_h + vm.vfront_porch;
>>
>> -     clk_disable(ldev->pixel_clk);
>> -
>> -     if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
>> -             DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
>> -             return;
>> -     }
>> -
>> -     clk_enable(ldev->pixel_clk);
>> -
>>       /* Configures the HS, VS, DE and PC polarities. Default Active Low */
>>       val = 0;
>>
>> @@ -528,6 +542,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc,
>>   }
>>
>>   static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
>> +     .mode_fixup = ltdc_crtc_mode_fixup,
>>       .mode_set_nofb = ltdc_crtc_mode_set_nofb,
>>       .atomic_flush = ltdc_crtc_atomic_flush,
>>       .atomic_enable = ltdc_crtc_atomic_enable,

Re: [PATCH] drm/stm: ltdc: use crtc_mode_fixup to update adjusted_mode clock

[Laurent Pinchart]

Hi Philippe,

On Thursday, 25 January 2018 18:01:01 EET Philippe Cornu wrote:
> There is a difference between the panel/bridge requested pixel clock
> value and the real one due to the hw platform clock preciseness (pll,
> dividers...). This patch updates the adjusted_mode clock value with
> the real hw clock value so then attached encoder & connector can use
> it for precise timing computations.
> 
> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
> ---
>  drivers/gpu/drm/stm/ltdc.c | 35 +++++++++++++++++++++++++----------
>  1 file changed, 25 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index b48589343ae1..90b3de516c91 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -428,12 +428,35 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc
> *crtc, reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
>  }
> 
> +static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
> +				 const struct drm_display_mode *mode,
> +				 struct drm_display_mode *adjusted_mode)
> +{
> +	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
> +	int rate = mode->clock * 1000;
> +
> +	/*
> +	 * TODO clk_round_rate() does not work yet. When ready, it can
> +	 * be used instead of clk_set_rate() then clk_get_rate().
> +	 */

Why does it fail ? Is it due to the STM clock source implementation ? This 
looks like a big hack, I'd rather see clk_round_rate() being fixed.

> +	clk_disable(ldev->pixel_clk);
> +	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
> +		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> +		return false;
> +	}
> +	clk_enable(ldev->pixel_clk);
> +
> +	adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
> +
> +	return true;
> +}
> +
>  static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
>  {
>  	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
>  	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>  	struct videomode vm;
> -	int rate = mode->clock * 1000;
>  	u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
>  	u32 total_width, total_height;
>  	u32 val;
> @@ -456,15 +479,6 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc
> *crtc) total_width = accum_act_w + vm.hfront_porch;
>  	total_height = accum_act_h + vm.vfront_porch;
> 
> -	clk_disable(ldev->pixel_clk);
> -
> -	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
> -		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
> -		return;
> -	}
> -
> -	clk_enable(ldev->pixel_clk);
> -
>  	/* Configures the HS, VS, DE and PC polarities. Default Active Low */
>  	val = 0;
> 
> @@ -528,6 +542,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc
> *crtc, }
> 
>  static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
> +	.mode_fixup = ltdc_crtc_mode_fixup,
>  	.mode_set_nofb = ltdc_crtc_mode_set_nofb,
>  	.atomic_flush = ltdc_crtc_atomic_flush,
>  	.atomic_enable = ltdc_crtc_atomic_enable,

-- 
Regards,

Laurent Pinchart

Re: [PATCH] drm/stm: ltdc: use crtc_mode_fixup to update adjusted_mode clock

[Benjamin Gaignard]

2018-01-29 11:43 GMT+01:00 Laurent Pinchart <laurent.pinchart@ideasonboard.com>:
> Hi Philippe,
>
> On Thursday, 25 January 2018 18:01:01 EET Philippe Cornu wrote:
>> There is a difference between the panel/bridge requested pixel clock
>> value and the real one due to the hw platform clock preciseness (pll,
>> dividers...). This patch updates the adjusted_mode clock value with
>> the real hw clock value so then attached encoder & connector can use
>> it for precise timing computations.
>>
>> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
>> ---
>>  drivers/gpu/drm/stm/ltdc.c | 35 +++++++++++++++++++++++++----------
>>  1 file changed, 25 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
>> index b48589343ae1..90b3de516c91 100644
>> --- a/drivers/gpu/drm/stm/ltdc.c
>> +++ b/drivers/gpu/drm/stm/ltdc.c
>> @@ -428,12 +428,35 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc
>> *crtc, reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);
>>  }
>>
>> +static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc,
>> +                              const struct drm_display_mode *mode,
>> +                              struct drm_display_mode *adjusted_mode)
>> +{
>> +     struct ltdc_device *ldev = crtc_to_ltdc(crtc);
>> +     int rate = mode->clock * 1000;
>> +
>> +     /*
>> +      * TODO clk_round_rate() does not work yet. When ready, it can
>> +      * be used instead of clk_set_rate() then clk_get_rate().
>> +      */
>
> Why does it fail ? Is it due to the STM clock source implementation ? This
> looks like a big hack, I'd rather see clk_round_rate() being fixed.

We have log the point and we will investigate it asap.

Regards,
Benjamin

>
>> +     clk_disable(ldev->pixel_clk);
>> +     if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
>> +             DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
>> +             return false;
>> +     }
>> +     clk_enable(ldev->pixel_clk);
>> +
>> +     adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;
>> +
>> +     return true;
>> +}
>> +
>>  static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
>>  {
>>       struct ltdc_device *ldev = crtc_to_ltdc(crtc);
>>       struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>>       struct videomode vm;
>> -     int rate = mode->clock * 1000;
>>       u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;
>>       u32 total_width, total_height;
>>       u32 val;
>> @@ -456,15 +479,6 @@ static void ltdc_crtc_mode_set_nofb(struct drm_crtc
>> *crtc) total_width = accum_act_w + vm.hfront_porch;
>>       total_height = accum_act_h + vm.vfront_porch;
>>
>> -     clk_disable(ldev->pixel_clk);
>> -
>> -     if (clk_set_rate(ldev->pixel_clk, rate) < 0) {
>> -             DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);
>> -             return;
>> -     }
>> -
>> -     clk_enable(ldev->pixel_clk);
>> -
>>       /* Configures the HS, VS, DE and PC polarities. Default Active Low */
>>       val = 0;
>>
>> @@ -528,6 +542,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc
>> *crtc, }
>>
>>  static const struct drm_crtc_helper_funcs ltdc_crtc_helper_funcs = {
>> +     .mode_fixup = ltdc_crtc_mode_fixup,
>>       .mode_set_nofb = ltdc_crtc_mode_set_nofb,
>>       .atomic_flush = ltdc_crtc_atomic_flush,
>>       .atomic_enable = ltdc_crtc_atomic_enable,
>
> --
> Regards,
>
> Laurent Pinchart
>