在 2017-06-07 17:38，Maxime Ripard 写道：
On Mon, Jun 05, 2017 at 12:01:45AM +0800, Icenowy Zheng wrote:
Allwinner H3 features a TV encoder similar to the one in earlier SoCs,
but has a internal fixed clock divider that divides the TCON1 clock
(called TVE clock in datasheet) by 11.
Add support for it.
Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
---
Changes in v2:
- Quirk part rewritten.
drivers/gpu/drm/sun4i/sun4i_tv.c | 35
++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tv.c
b/drivers/gpu/drm/sun4i/sun4i_tv.c
index 338b9e5bb2a3..b9ff6d5ea67a 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tv.c
@@ -13,6 +13,7 @@
#include <linux/clk.h>
#include <linux/component.h>
#include <linux/of_address.h>
+#include <linux/of_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>
@@ -169,14 +170,21 @@ struct tv_mode {
const struct resync_parameters *resync_params;
};
+struct sun4i_tv_quirks {
+ int fixed_divider;
+};
+
struct sun4i_tv {
struct drm_connector connector;
struct drm_encoder encoder;
struct clk *clk;
+ struct clk *mod_clk;
struct regmap *regs;
struct reset_control *reset;
+ const struct sun4i_tv_quirks *quirks;
+
struct sun4i_drv *drv;
};
@@ -391,6 +399,12 @@ static void sun4i_tv_mode_set(struct drm_encoder
*encoder,
struct sun4i_tcon *tcon = crtc->tcon;
const struct tv_mode *tv_mode = sun4i_tv_find_tv_by_mode(mode);
+ if (tv->quirks->fixed_divider) {
+ DRM_DEBUG_DRIVER("Applying fixed divider %d on TVE clock\n",
+ tv->quirks->fixed_divider);
+ mode->crtc_clock *= tv->quirks->fixed_divider;
+ }
+
You're not allowed to change the mode in mode_set, and you shouldn't
even change it. The output pixel clock is still 27MHz.
You should implement that using the states, as we discussed already.
After reading the comments at include/drm/drm_modeset_helper_vtables.h,
I think the atomic_check function is allowed to directly change
the adjust_mode of crtc_state.
And according to other comments at include/drm/drm_modes.h, the
crtc_clock in adjust_mode should be the clock to be really feed
to the hardware.
So I think I can just change this in atomic_check.
However, the mode_set function of sun4i_tv seems to be not
regarding adjusted_mode and still use original mode.
So my current design is:
- Multiply adjusted_mode in atomic_check.
- Feed adjust_mode to TCON code in mode_set function.
Is this proper?
(From my own understanding to the comments I think so.)
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