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drm/stm: ltdc: filter mode pixel clock vs pad constraint 

Filter the requested mode pixel clock frequency according
to the pad maximum supported frequency.

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Tested-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1530271342-5532-1-git-send-email-yannick.fertre@st.com
This commit is contained in:
Yannick Fertre 2018-06-29 13:22:22 +02:00 committed by Benjamin Gaignard
parent f8878bb2f8
commit 7868e50792
2 changed files with 13 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/gpu/drm/stm/ltdc.c
View File

@ -457,6 +457,14 @@ ltdc_crtc_mode_valid(struct drm_crtc *crtc,
int target_max = target + CLK_TOLERANCE_HZ;
int result;
result = clk_round_rate(ldev->pixel_clk, target);
DRM_DEBUG_DRIVER("clk rate target %d, available %d\n", target, result);
/* Filter modes according to the max frequency supported by the pads */
if (result > ldev->caps.pad_max_freq_hz)
return MODE_CLOCK_HIGH;
/*
* Accept all "preferred" modes:
* - this is important for panels because panel clock tolerances are
@ -468,10 +476,6 @@ ltdc_crtc_mode_valid(struct drm_crtc *crtc,
if (mode->type & DRM_MODE_TYPE_PREFERRED)
return MODE_OK;
result = clk_round_rate(ldev->pixel_clk, target);
DRM_DEBUG_DRIVER("clk rate target %d, available %d\n", target, result);
/*
* Filter modes according to the clock value, particularly useful for
* hdmi modes that require precise pixel clocks.
@ -991,11 +995,15 @@ static int ltdc_get_caps(struct drm_device *ddev)
* does not work on 2nd layer.
*/
ldev->caps.non_alpha_only_l1 = true;
ldev->caps.pad_max_freq_hz = 90000000;
if (ldev->caps.hw_version == HWVER_10200)
ldev->caps.pad_max_freq_hz = 65000000;
break;
case HWVER_20101:
ldev->caps.reg_ofs = REG_OFS_4;
ldev->caps.pix_fmt_hw = ltdc_pix_fmt_a1;
ldev->caps.non_alpha_only_l1 = false;
ldev->caps.pad_max_freq_hz = 150000000;
break;
default:
return -ENODEV;

1
drivers/gpu/drm/stm/ltdc.h
View File

@ -18,6 +18,7 @@ struct ltdc_caps {
u32 bus_width; /* bus width (32 or 64 bits) */
const u32 *pix_fmt_hw; /* supported pixel formats */
bool non_alpha_only_l1; /* non-native no-alpha formats on layer 1 */
int pad_max_freq_hz; /* max frequency supported by pad */
};
#define LTDC_MAX_LAYER 4