[PATCH v4 29/38] mmc: exynos_dw_mmc: Read and use DDR timing when available

[Sam Protsenko]

DDR timing values should be defined in "samsung,dw-mshc-ddr-timing" dts
property, and used when DDR MMC mode is selected. Read that value from
dts and use it. If it's not available, use SDR timing values instead.
This change is following upstream Linux kernel implementation.

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
Changes in v4:
  - (none)

Changes in v3:
  - (none)

Changes in v2:
  - (none)

 drivers/mmc/exynos_dw_mmc.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/exynos_dw_mmc.c b/drivers/mmc/exynos_dw_mmc.c
index b9d655c0d5c8..32f3ea168b6c 100644
--- a/drivers/mmc/exynos_dw_mmc.c
+++ b/drivers/mmc/exynos_dw_mmc.c
@@ -52,6 +52,7 @@ struct dwmci_exynos_priv_data {
 #endif
 	struct clk clk;
 	u32 sdr_timing;
+	u32 ddr_timing;
 	const struct exynos_dwmmc_variant *chip;
 };
 
@@ -127,8 +128,14 @@ static int exynos_dwmmc_set_sclk(struct dwmci_host *host, unsigned long rate)
 static int exynos_dwmci_clksel(struct dwmci_host *host)
 {
 	struct dwmci_exynos_priv_data *priv = exynos_dwmmc_get_priv(host);
+	u32 timing;
 
-	dwmci_writel(host, priv->chip->clksel, priv->sdr_timing);
+	if (host->mmc->selected_mode == MMC_DDR_52)
+		timing = priv->ddr_timing;
+	else
+		timing = priv->sdr_timing;
+
+	dwmci_writel(host, priv->chip->clksel, timing);
 
 	return 0;
 }
@@ -305,6 +312,17 @@ static int exynos_dwmmc_of_to_plat(struct udevice *dev)
 			priv->sdr_timing = DWMMC_MMC2_SDR_TIMING_VAL;
 	}
 
+	err = dev_read_u32_array(dev, "samsung,dw-mshc-ddr-timing", timing, 2);
+	if (err) {
+		debug("DWMMC%d: Can't get ddr-timings, using sdr-timings\n",
+		      host->dev_index);
+		priv->ddr_timing = priv->sdr_timing;
+	} else {
+		priv->ddr_timing = DWMCI_SET_SAMPLE_CLK(timing[0]) |
+				   DWMCI_SET_DRV_CLK(timing[1]) |
+				   DWMCI_SET_DIV_RATIO(div);
+	}
+
 	host->fifo_depth = dev_read_u32_default(dev, "fifo-depth", 0);
 	host->bus_hz = dev_read_u32_default(dev, "clock-frequency", 0);
 
-- 
2.39.2