[PATCH v11 5/6] drm/mediatek: dpi sample mode support

Jitao Shi
2020-02-28T08:15:59Z

DPI can sample on falling, rising or both edge.
When DPI sample the data both rising and falling edge.
It can reduce half data io pins.

Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
drivers/gpu/drm/mediatek/mtk_dpi.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
index 087f5ce732e1..db3272f7a4c4 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -75,6 +75,7 @@ struct mtk_dpi {
enum mtk_dpi_out_bit_num bit_num;
enum mtk_dpi_out_channel_swap channel_swap;
int refcount;
+ u32 pclk_sample;
};

static inline struct mtk_dpi *mtk_dpi_from_encoder(struct drm_encoder *e)
@@ -348,6 +349,13 @@ static void mtk_dpi_config_disable_edge(struct mtk_dpi *dpi)
mtk_dpi_mask(dpi, dpi->conf->reg_h_fre_con, 0, EDGE_SEL_EN);
}

+static void mtk_dpi_enable_pclk_sample_dual_edge(struct mtk_dpi *dpi)
+{
+ mtk_dpi_mask(dpi, DPI_DDR_SETTING, DDR_EN | DDR_4PHASE,
+ DDR_EN | DDR_4PHASE);
+ mtk_dpi_mask(dpi, DPI_OUTPUT_SETTING, EDGE_SEL, EDGE_SEL);
+}
+
static void mtk_dpi_config_color_format(struct mtk_dpi *dpi,
enum mtk_dpi_out_color_format format)
{
@@ -439,7 +447,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
pll_rate = clk_get_rate(dpi->tvd_clk);

vm.pixelclock = pll_rate / factor;
- clk_set_rate(dpi->pixel_clk, vm.pixelclock);
+ clk_set_rate(dpi->pixel_clk,
+ vm.pixelclock * (dpi->pclk_sample > 1 ? 2 : 1));
vm.pixelclock = clk_get_rate(dpi->pixel_clk);

dev_dbg(dpi->dev, "Got PLL %lu Hz, pixel clock %lu Hz\n",
@@ -450,7 +459,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
limit.y_bottom = 0x0010;
limit.y_top = 0x0FE0;

- dpi_pol.ck_pol = MTK_DPI_POLARITY_FALLING;
+ dpi_pol.ck_pol = dpi->pclk_sample == 1 ?
+ MTK_DPI_POLARITY_RISING : MTK_DPI_POLARITY_FALLING;
dpi_pol.de_pol = MTK_DPI_POLARITY_RISING;
dpi_pol.hsync_pol = vm.flags & DISPLAY_FLAGS_HSYNC_HIGH ?
MTK_DPI_POLARITY_FALLING : MTK_DPI_POLARITY_RISING;
@@ -504,6 +514,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
mtk_dpi_config_color_format(dpi, dpi->color_format);
mtk_dpi_config_2n_h_fre(dpi);
mtk_dpi_config_disable_edge(dpi);
+ if (dpi->pclk_sample > 1)
+ mtk_dpi_enable_pclk_sample_dual_edge(dpi);
mtk_dpi_sw_reset(dpi, false);

return 0;
@@ -704,6 +716,8 @@ static int mtk_dpi_probe(struct platform_device *pdev)

dpi->dev = dev;
dpi->conf = (struct mtk_dpi_conf *)of_device_get_match_data(dev);
+ of_property_read_u32_index(dev->of_node, "pclk-sample", 1,
+ &dpi->pclk_sample);

mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dpi->regs = devm_ioremap_resource(dev, mem);
--
2.21.0