The early Integrator CLCD synthesized in the Integrator CP and
IM-PD1 FPGAs are broken: their clock dividers do not work
properly. Support disabling the clock divider and drive the
clock directly from the parent under these circumstances.
Reviewed-by: Eric Anholt <e...@anholt.net>
Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
---
ChangeLog ->v3:
- Collect Eric's Review tag.
---
drivers/gpu/drm/pl111/pl111_display.c | 8 ++++++++
drivers/gpu/drm/pl111/pl111_drm.h | 3 +++
drivers/gpu/drm/pl111/pl111_versatile.c | 1 +
3 files changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/pl111/pl111_display.c
b/drivers/gpu/drm/pl111/pl111_display.c
index 55ada00ec974..4d4e38b4c9d5 100644
--- a/drivers/gpu/drm/pl111/pl111_display.c
+++ b/drivers/gpu/drm/pl111/pl111_display.c
@@ -138,6 +138,9 @@ static void pl111_display_enable(struct
drm_simple_display_pipe *pipe,
tim2 = readl(priv->regs + CLCD_TIM2);
tim2 &= (TIM2_BCD | TIM2_PCD_LO_MASK | TIM2_PCD_HI_MASK);
+ if (priv->variant->broken_clockdivider)
+ tim2 |= TIM2_BCD;
+
if (mode->flags & DRM_MODE_FLAG_NHSYNC)
tim2 |= TIM2_IHS;
@@ -455,6 +458,11 @@ pl111_init_clock_divider(struct drm_device *drm)
dev_err(drm->dev, "CLCD: unable to get clcdclk.\n");
return PTR_ERR(parent);
}
+ /* If the clock divider is broken, use the parent directly */
+ if (priv->variant->broken_clockdivider) {
+ priv->clk = parent;
+ return 0;
+ }
parent_name = __clk_get_name(parent);
spin_lock_init(&priv->tim2_lock);
diff --git a/drivers/gpu/drm/pl111/pl111_drm.h
b/drivers/gpu/drm/pl111/pl111_drm.h
index c2f410f0b12e..f75c5d4645b2 100644
--- a/drivers/gpu/drm/pl111/pl111_drm.h
+++ b/drivers/gpu/drm/pl111/pl111_drm.h
@@ -38,6 +38,8 @@ struct drm_minor;
* @is_pl110: this is the early PL110 variant
* @external_bgr: this is the Versatile Pl110 variant with external
* BGR/RGB routing
+ * @broken_clockdivider: the clock divider is broken and we need to
+ * use the supplied clock directly
* @formats: array of supported pixel formats on this variant
* @nformats: the length of the array of supported pixel formats
*/
@@ -45,6 +47,7 @@ struct pl111_variant_data {
const char *name;
bool is_pl110;
bool external_bgr;
+ bool broken_clockdivider;
const u32 *formats;
unsigned int nformats;
};
diff --git a/drivers/gpu/drm/pl111/pl111_versatile.c
b/drivers/gpu/drm/pl111/pl111_versatile.c
index ec05c7e5319b..93cf2d82074b 100644
--- a/drivers/gpu/drm/pl111/pl111_versatile.c
+++ b/drivers/gpu/drm/pl111/pl111_versatile.c
@@ -237,6 +237,7 @@ static const u32 pl110_versatile_pixel_formats[] = {
static const struct pl111_variant_data pl110_integrator = {
.name = "PL110 Integrator",
.is_pl110 = true,
+ .broken_clockdivider = true,
.formats = pl110_integrator_pixel_formats,
.nformats = ARRAY_SIZE(pl110_integrator_pixel_formats),
};
--
2.14.3
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