[PATCH v2 4/4] drm/mediatek: config mipitx impedance with calibration data

[Jitao Shi <jitao.shi@xxxxxxxxxxxx>]

Read calibration data from nvmem, and config mipitx impedance with
calibration data to make sure their impedance are 100ohm.

Signed-off-by: Jitao Shi <jitao.shi@xxxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c b/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c
index 124fdf95f1e5..878feeb7ac6c 100644
--- a/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c
+++ b/drivers/gpu/drm/mediatek/mtk_mt8183_mipi_tx.c
@@ -5,6 +5,8 @@
  */
 
 #include "mtk_mipi_tx.h"
+#include <linux/nvmem-consumer.h>
+#include <linux/slab.h>
 
 #define MIPITX_LANE_CON		0x000c
 #define RG_DSI_CPHY_T1DRV_EN		BIT(0)
@@ -28,6 +30,7 @@
 #define MIPITX_PLL_CON4		0x003c
 #define RG_DSI_PLL_IBIAS		(3 << 10)
 
+#define MIPITX_D2P_RTCODE	0x0100
 #define MIPITX_D2_SW_CTL_EN	0x0144
 #define MIPITX_D0_SW_CTL_EN	0x0244
 #define MIPITX_CK_CKMODE_EN	0x0328
@@ -108,6 +111,58 @@ static const struct clk_ops mtk_mipi_tx_pll_ops = {
 	.recalc_rate = mtk_mipi_tx_pll_recalc_rate,
 };
 
+static void mtk_mipi_tx_config_calibration_data(struct mtk_mipi_tx *mipi_tx)
+{
+	u32 *buf;
+	u32 rt_code[5];
+	int i, j;
+	struct nvmem_cell *cell;
+	struct device *dev = mipi_tx->dev;
+	size_t len;
+
+	cell = nvmem_cell_get(dev, "calibration-data");
+	if (IS_ERR(cell)) {
+		dev_info(dev, "nvmem_cell_get fail\n");
+		return;
+	}
+
+	buf = (u32 *)nvmem_cell_read(cell, &len);
+
+	nvmem_cell_put(cell);
+
+	if (IS_ERR(buf)) {
+		dev_info(dev, "can't get data\n");
+		return;
+	}
+
+	if (len < 3 * sizeof(u32)) {
+		dev_info(dev, "invalid calibration data\n");
+		kfree(buf);
+		return;
+	}
+
+	rt_code[0] = ((buf[0] >> 6 & 0x1f) << 5) | (buf[0] >> 11 & 0x1f);
+	rt_code[1] = ((buf[1] >> 27 & 0x1f) << 5) | (buf[0] >> 1 & 0x1f);
+	rt_code[2] = ((buf[1] >> 17 & 0x1f) << 5) | (buf[1] >> 22 & 0x1f);
+	rt_code[3] = ((buf[1] >> 7 & 0x1f) << 5) | (buf[1] >> 12 & 0x1f);
+	rt_code[4] = ((buf[2] >> 27 & 0x1f) << 5) | (buf[1] >> 2 & 0x1f);
+
+	for (i = 0; i < 5; i++) {
+		if ((rt_code[i] & 0x1f) == 0)
+			rt_code[i] |= 0x10;
+
+		if ((rt_code[i] >> 5 & 0x1f) == 0)
+			rt_code[i] |= 0x10 << 5;
+
+		for (j = 0; j < 10; j++)
+			mtk_mipi_tx_update_bits(mipi_tx,
+				MIPITX_D2P_RTCODE * (i + 1) + j * 4,
+				1, rt_code[i] >> j & 1);
+	}
+
+	kfree(buf);
+}
+
 static void mtk_mipi_tx_power_on_signal(struct phy *phy)
 {
 	struct mtk_mipi_tx *mipi_tx = phy_get_drvdata(phy);
@@ -130,6 +185,8 @@ static void mtk_mipi_tx_power_on_signal(struct phy *phy)
 				RG_DSI_HSTX_LDO_REF_SEL,
 				mipi_tx->mipitx_drive << 6);
 
+	mtk_mipi_tx_config_calibration_data(mipi_tx);
+
 	mtk_mipi_tx_set_bits(mipi_tx, MIPITX_CK_CKMODE_EN, DSI_CK_CKMODE_EN);
 }
 
-- 
2.21.0