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

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