mmc: sdhci-sprd: Add optional gate clock support

For the Spreadtrum SC9860 platform, we should enable another gate clock
'2x_enable' to make the SD host controller work well.
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

@@ -60,6 +60,7 @@ struct sdhci_sprd_host {
 	u32 version;
 	struct clk *clk_sdio;
 	struct clk *clk_enable;
+	struct clk *clk_2x_enable;
 	u32 base_rate;
 	int flags; /* backup of host attribute */
 };
@@ -364,6 +365,10 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
 	}
 	sprd_host->clk_enable = clk;
 
+	clk = devm_clk_get(&pdev->dev, "2x_enable");
+	if (!IS_ERR(clk))
+		sprd_host->clk_2x_enable = clk;
+
 	ret = clk_prepare_enable(sprd_host->clk_sdio);
 	if (ret)
 		goto pltfm_free;
@@ -372,6 +377,10 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
 	if (ret)
 		goto clk_disable;
 
+	ret = clk_prepare_enable(sprd_host->clk_2x_enable);
+	if (ret)
+		goto clk_disable2;
+
 	sdhci_sprd_init_config(host);
 	host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
 	sprd_host->version = ((host->version & SDHCI_VENDOR_VER_MASK) >>
@@ -408,6 +417,9 @@ static int sdhci_sprd_probe(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
 
+	clk_disable_unprepare(sprd_host->clk_2x_enable);
+
+clk_disable2:
 	clk_disable_unprepare(sprd_host->clk_enable);
 
 clk_disable:
@@ -427,6 +439,7 @@ static int sdhci_sprd_remove(struct platform_device *pdev)
 	mmc_remove_host(mmc);
 	clk_disable_unprepare(sprd_host->clk_sdio);
 	clk_disable_unprepare(sprd_host->clk_enable);
+	clk_disable_unprepare(sprd_host->clk_2x_enable);
 
 	mmc_free_host(mmc);
 
@@ -449,6 +462,7 @@ static int sdhci_sprd_runtime_suspend(struct device *dev)
 
 	clk_disable_unprepare(sprd_host->clk_sdio);
 	clk_disable_unprepare(sprd_host->clk_enable);
+	clk_disable_unprepare(sprd_host->clk_2x_enable);
 
 	return 0;
 }
@@ -459,19 +473,28 @@ static int sdhci_sprd_runtime_resume(struct device *dev)
 	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
 	int ret;
 
-	ret = clk_prepare_enable(sprd_host->clk_enable);
+	ret = clk_prepare_enable(sprd_host->clk_2x_enable);
 	if (ret)
 		return ret;
 
+	ret = clk_prepare_enable(sprd_host->clk_enable);
+	if (ret)
+		goto clk_2x_disable;
+
 	ret = clk_prepare_enable(sprd_host->clk_sdio);
-	if (ret) {
-		clk_disable_unprepare(sprd_host->clk_enable);
-		return ret;
-	}
+	if (ret)
+		goto clk_disable;
 
 	sdhci_runtime_resume_host(host);
-
 	return 0;
+
+clk_disable:
+	clk_disable_unprepare(sprd_host->clk_enable);
+
+clk_2x_disable:
+	clk_disable_unprepare(sprd_host->clk_2x_enable);
+
+	return ret;
 }
 #endif