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drm/bridge: analogix_dp: Add support for SSC (Spread-Spectrum Clock)

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DPTX implements the programmable SSC down-spreading with up to
0.5% modulation amplitude and 30k/33k modulation frequency.

Change-Id: I2c3eae8f27c84eb1b22eac8973691e0276c1588e
Signed-off-by: Wyon Bi <bivvy.bi@rock-chips.com>
This commit is contained in:
Wyon Bi
2019-01-09 10:05:25 +08:00
committed by Tao Huang
parent d307d5d0d3
commit 10aad71a4d
3 changed files with 35 additions and 0 deletions
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31
drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
View File

@@ -618,6 +618,32 @@ int analogix_dp_write_byte_to_dpcd(struct analogix_dp_device *dp,
return retval;
}
static void analogix_dp_ssc_enable(struct analogix_dp_device *dp)
{
u32 reg;
/* 4500ppm */
writel(0x19, dp->reg_base + ANALOIGX_DP_SSC_REG);
/*
* To apply updated SSC parameters into SSC operation,
* firmware must disable and enable this bit.
*/
reg = readl(dp->reg_base + ANALOGIX_DP_FUNC_EN_2);
reg |= SSC_FUNC_EN_N;
writel(reg, dp->reg_base + ANALOGIX_DP_FUNC_EN_2);
reg &= ~SSC_FUNC_EN_N;
writel(reg, dp->reg_base + ANALOGIX_DP_FUNC_EN_2);
}
static void analogix_dp_ssc_disable(struct analogix_dp_device *dp)
{
u32 reg;
reg = readl(dp->reg_base + ANALOGIX_DP_FUNC_EN_2);
reg |= SSC_FUNC_EN_N;
writel(reg, dp->reg_base + ANALOGIX_DP_FUNC_EN_2);
}
bool analogix_dp_ssc_supported(struct analogix_dp_device *dp)
{
/* Check if SSC is supported by both sides */
@@ -648,6 +674,11 @@ void analogix_dp_set_link_bandwidth(struct analogix_dp_device *dp, u32 bwtype)
__func__, ret);
return;
}
} else {
if (analogix_dp_ssc_supported(dp))
analogix_dp_ssc_enable(dp);
else
analogix_dp_ssc_disable(dp);
}
ret = readx_poll_timeout(analogix_dp_get_pll_lock_status, dp, status,

1
drivers/gpu/drm/bridge/analogix/analogix_dp_reg.h
View File

@@ -48,6 +48,7 @@
#define ANALOGIX_DP_PLL_REG_4 0x9ec
#define ANALOGIX_DP_PLL_REG_5 0xa00
#define ANALOIGX_DP_SSC_REG 0x104
#define ANALOGIX_DP_PD 0x12c
#define ANALOGIX_DP_IF_TYPE 0x244

3
drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
View File

@@ -678,10 +678,12 @@ static const struct rockchip_dp_chip_data rk3399_edp = {
.lcdsel_big = HIWORD_UPDATE(0, RK3399_EDP_LCDC_SEL),
.lcdsel_lit = HIWORD_UPDATE(RK3399_EDP_LCDC_SEL, RK3399_EDP_LCDC_SEL),
.chip_type = RK3399_EDP,
.ssc = true,
};
static const struct rockchip_dp_chip_data rk3368_edp = {
.chip_type = RK3368_EDP,
.ssc = true,
};
static const struct rockchip_dp_chip_data rk3288_dp = {
@@ -689,6 +691,7 @@ static const struct rockchip_dp_chip_data rk3288_dp = {
.lcdsel_big = HIWORD_UPDATE(0, RK3288_EDP_LCDC_SEL),
.lcdsel_lit = HIWORD_UPDATE(RK3288_EDP_LCDC_SEL, RK3288_EDP_LCDC_SEL),
.chip_type = RK3288_DP,
.ssc = true,
};
static const struct rockchip_dp_chip_data rk3568_edp = {