[PATCH v3 04/10] drm/bridge: analogix_dp: some rockchip chips need to flip REF_CLK bit setting

[Yakir Yang <ykk@rock-chips.com>]

As vendor document indicate, when REF_CLK bit set 0, then DP
phy's REF_CLK should switch to 24M source clock.

But due to IC PHY layout mistaken, some chips need to flip this
bit(like RK3288), and unfortunately they didn't indicate in the
DP version register. That's why we have to make this little hack.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
---
Changes in v3:
- Make this hack code more clear (Tomasz, reviewed at Google Gerrit)
  reg = ~reg & REF_CLK_MASK;  --->  reg ^= REF_CLK_MASK;
    [https://chromium-review.googlesource.com/#/c/346852/7/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c@80]
- Add tested flag from Javier

Changes in v2:
- new patch in v2

 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 6 +++++-
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.h | 1 +
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c   | 3 +++
 include/drm/bridge/analogix_dp.h                  | 5 +++++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 931a76c..97ced6b 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -75,7 +75,11 @@ void analogix_dp_init_analog_param(struct analogix_dp_device *dp)
 	writel(reg, dp->reg_base + ANALOGIX_DP_ANALOG_CTL_2);
 
 	if (dp->plat_data && (dp->plat_data->dev_type == ROCKCHIP_DP)) {
-		writel(REF_CLK_24M, dp->reg_base + ANALOGIX_DP_PLL_REG_1);
+		reg = REF_CLK_24M;
+		if (dp->plat_data->subdev_type == RK3288_DP)
+			reg ^= REF_CLK_MASK;
+
+		writel(reg, dp->reg_base + ANALOGIX_DP_PLL_REG_1);
 		writel(0x95, dp->reg_base + ANALOGIX_DP_PLL_REG_2);
 		writel(0x40, dp->reg_base + ANALOGIX_DP_PLL_REG_3);
 		writel(0x58, dp->reg_base + ANALOGIX_DP_PLL_REG_4);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.h
index 88d56ad..cdcc6c5 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.h
@@ -165,6 +165,7 @@
 /* ANALOGIX_DP_PLL_REG_1 */
 #define REF_CLK_24M				(0x1 << 0)
 #define REF_CLK_27M				(0x0 << 0)
+#define REF_CLK_MASK				(0x1 << 0)
 
 /* ANALOGIX_DP_LANE_MAP */
 #define LANE3_MAP_LOGIC_LANE_0			(0x0 << 6)
diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 3855f46..315ebba 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -46,6 +46,7 @@ struct rockchip_dp_chip_data {
 	u32	lcdsel_grf_reg;
 	u32	lcdsel_big;
 	u32	lcdsel_lit;
+	u32	chip_type;
 };
 
 struct rockchip_dp_device {
@@ -286,6 +287,7 @@ static int rockchip_dp_bind(struct device *dev, struct device *master,
 	dp->plat_data.encoder = &dp->encoder;
 
 	dp->plat_data.dev_type = ROCKCHIP_DP;
+	dp->plat_data.subdev_type = dp_data->chip_type;
 	dp->plat_data.power_on = rockchip_dp_poweron;
 	dp->plat_data.power_off = rockchip_dp_powerdown;
 
@@ -384,6 +386,7 @@ static const struct rockchip_dp_chip_data rk3288_dp = {
 	.lcdsel_grf_reg = 0x025c,
 	.lcdsel_big = 0 | BIT(21),
 	.lcdsel_lit = BIT(5) | BIT(21),
+	.chip_type = RK3288_DP,
 };
 
 static const struct of_device_id rockchip_dp_dt_ids[] = {
diff --git a/include/drm/bridge/analogix_dp.h b/include/drm/bridge/analogix_dp.h
index 9e5d013..06c0250 100644
--- a/include/drm/bridge/analogix_dp.h
+++ b/include/drm/bridge/analogix_dp.h
@@ -18,8 +18,13 @@ enum analogix_dp_devtype {
 	ROCKCHIP_DP,
 };
 
+enum analogix_dp_sub_devtype {
+	RK3288_DP,
+};
+
 struct analogix_dp_plat_data {
 	enum analogix_dp_devtype dev_type;
+	enum analogix_dp_sub_devtype subdev_type;
 	struct drm_panel *panel;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;
-- 
1.9.1