mmc: sdhci-sprd: Add PHY DLL delay configuration

Set the PHY DLL delay for each timing mode, which is used to sample the clock
accurately and make the clock more stable.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-sprd.c

@@ -29,6 +29,8 @@
 #define  SDHCI_SPRD_DLL_INIT_COUNT	0xc00
 #define  SDHCI_SPRD_DLL_PHASE_INTERNAL	0x3
 
+#define SDHCI_SPRD_REG_32_DLL_DLY	0x204
+
 #define SDHCI_SPRD_REG_32_DLL_DLY_OFFSET	0x208
 #define  SDHCIBSPRD_IT_WR_DLY_INV		BIT(5)
 #define  SDHCI_SPRD_BIT_CMD_DLY_INV		BIT(13)
@@ -72,6 +74,24 @@ struct sdhci_sprd_host {
 	struct clk *clk_2x_enable;
 	u32 base_rate;
 	int flags; /* backup of host attribute */
+	u32 phy_delay[MMC_TIMING_MMC_HS400 + 2];
+};
+
+struct sdhci_sprd_phy_cfg {
+	const char *property;
+	u8 timing;
+};
+
+static const struct sdhci_sprd_phy_cfg sdhci_sprd_phy_cfgs[] = {
+	{ "sprd,phy-delay-legacy", MMC_TIMING_LEGACY, },
+	{ "sprd,phy-delay-sd-highspeed", MMC_TIMING_SD_HS, },
+	{ "sprd,phy-delay-sd-uhs-sdr50", MMC_TIMING_UHS_SDR50, },
+	{ "sprd,phy-delay-sd-uhs-sdr104", MMC_TIMING_UHS_SDR104, },
+	{ "sprd,phy-delay-mmc-highspeed", MMC_TIMING_MMC_HS, },
+	{ "sprd,phy-delay-mmc-ddr52", MMC_TIMING_MMC_DDR52, },
+	{ "sprd,phy-delay-mmc-hs200", MMC_TIMING_MMC_HS200, },
+	{ "sprd,phy-delay-mmc-hs400", MMC_TIMING_MMC_HS400, },
+	{ "sprd,phy-delay-mmc-hs400es", MMC_TIMING_MMC_HS400 + 1, },
 };
 
 #define TO_SPRD_HOST(host) sdhci_pltfm_priv(sdhci_priv(host))
@@ -276,6 +296,9 @@ static unsigned int sdhci_sprd_get_min_clock(struct sdhci_host *host)
 static void sdhci_sprd_set_uhs_signaling(struct sdhci_host *host,
 					 unsigned int timing)
 {
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+	struct mmc_host *mmc = host->mmc;
+	u32 *p = sprd_host->phy_delay;
 	u16 ctrl_2;
 
 	if (timing == host->timing)
@@ -314,6 +337,9 @@ static void sdhci_sprd_set_uhs_signaling(struct sdhci_host *host,
 	}
 
 	sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
+
+	if (!mmc->ios.enhanced_strobe)
+		sdhci_writel(host, p[timing], SDHCI_SPRD_REG_32_DLL_DLY);
 }
 
 static void sdhci_sprd_hw_reset(struct sdhci_host *host)
@@ -381,6 +407,8 @@ static void sdhci_sprd_hs400_enhanced_strobe(struct mmc_host *mmc,
 					     struct mmc_ios *ios)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+	u32 *p = sprd_host->phy_delay;
 	u16 ctrl_2;
 
 	if (!ios->enhanced_strobe)
@@ -395,6 +423,28 @@ static void sdhci_sprd_hs400_enhanced_strobe(struct mmc_host *mmc,
 	sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
 
 	sdhci_sprd_sd_clk_on(host);
+
+	/* Set the PHY DLL delay value for HS400 enhanced strobe mode */
+	sdhci_writel(host, p[MMC_TIMING_MMC_HS400 + 1],
+		     SDHCI_SPRD_REG_32_DLL_DLY);
+}
+
+static void sdhci_sprd_phy_param_parse(struct sdhci_sprd_host *sprd_host,
+				       struct device_node *np)
+{
+	u32 *p = sprd_host->phy_delay;
+	int ret, i, index;
+	u32 val[4];
+
+	for (i = 0; i < ARRAY_SIZE(sdhci_sprd_phy_cfgs); i++) {
+		ret = of_property_read_u32_array(np,
+				sdhci_sprd_phy_cfgs[i].property, val, 4);
+		if (ret)
+			continue;
+
+		index = sdhci_sprd_phy_cfgs[i].timing;
+		p[index] = val[0] | (val[1] << 8) | (val[2] << 16) | (val[3] << 24);
+	}
 }
 
 static const struct sdhci_pltfm_data sdhci_sprd_pdata = {
@@ -428,6 +478,7 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
 		goto pltfm_free;
 
 	sprd_host = TO_SPRD_HOST(host);
+	sdhci_sprd_phy_param_parse(sprd_host, pdev->dev.of_node);
 
 	clk = devm_clk_get(&pdev->dev, "sdio");
 	if (IS_ERR(clk)) {