mmc: host: sdhci-tegra: Add set_clock op

Add a set_clock op to sdhci-tegra to allow the clock to be
disabled.  Also add suspend and resume ops to disable
the clock before suspend, and enable it during resume.

Change-Id: I239cb769b54c83a1bd4a80b73e1c4845ce2d165d
Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 61 insertions, 2 deletions

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index 58be962bcb26..bc5adbf65f59 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -18,6 +18,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
+#include <linux/slab.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
 
@@ -26,6 +27,12 @@
 
 #include "sdhci-pltfm.h"
 
+#define SDHCI_VENDOR_CLOCK_CNTRL       0x100
+
+struct tegra_sdhci_host {
+	bool	clk_enabled;
+};
+
 static u32 tegra_sdhci_readl(struct sdhci_host *host, int reg)
 {
 	u32 val;
@@ -145,12 +152,48 @@ static int tegra_sdhci_8bit(struct sdhci_host *host, int bus_width)
 	return 0;
 }
 
+static void tegra_sdhci_set_clock(struct sdhci_host *sdhci, unsigned int clock)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(sdhci);
+	struct tegra_sdhci_host *tegra_host = pltfm_host->priv;
+
+	pr_debug("%s %s %u enabled=%u\n", __func__,
+		mmc_hostname(sdhci->mmc), clock, tegra_host->clk_enabled);
+
+	if (clock && !tegra_host->clk_enabled) {
+		clk_enable(pltfm_host->clk);
+		sdhci_writeb(sdhci, 1, SDHCI_VENDOR_CLOCK_CNTRL);
+		tegra_host->clk_enabled = true;
+	} else if (!clock && tegra_host->clk_enabled) {
+		sdhci_writeb(sdhci, 0, SDHCI_VENDOR_CLOCK_CNTRL);
+		clk_disable(pltfm_host->clk);
+		tegra_host->clk_enabled = false;
+	}
+}
+
+static int tegra_sdhci_suspend(struct sdhci_host *sdhci, pm_message_t state)
+{
+	tegra_sdhci_set_clock(sdhci, 0);
+
+	return 0;
+}
+
+static int tegra_sdhci_resume(struct sdhci_host *sdhci)
+{
+	tegra_sdhci_set_clock(sdhci, 1);
+
+	return 0;
+}
+
 static struct sdhci_ops tegra_sdhci_ops = {
 	.get_ro     = tegra_sdhci_get_ro,
 	.read_l     = tegra_sdhci_readl,
 	.read_w     = tegra_sdhci_readw,
 	.write_l    = tegra_sdhci_writel,
 	.platform_8bit_width = tegra_sdhci_8bit,
+	.set_clock  = tegra_sdhci_set_clock,
+	.suspend    = tegra_sdhci_suspend,
+	.resume     = tegra_sdhci_resume,
 };
 
 static struct sdhci_pltfm_data sdhci_tegra_pdata = {
@@ -166,6 +209,7 @@ static int __devinit sdhci_tegra_probe(struct platform_device *pdev)
 	struct sdhci_pltfm_host *pltfm_host;
 	struct tegra_sdhci_platform_data *plat;
 	struct sdhci_host *host;
+	struct tegra_sdhci_host *tegra_host;
 	struct clk *clk;
 	int rc;
 
@@ -183,6 +227,12 @@ static int __devinit sdhci_tegra_probe(struct platform_device *pdev)
 		goto err_no_plat;
 	}
 
+	tegra_host = kzalloc(sizeof(struct tegra_sdhci_host), GFP_KERNEL);
+	if (tegra_host == NULL) {
+		dev_err(mmc_dev(host->mmc), "failed to allocate tegra host\n");
+		return -ENOMEM;
+	}
+
 #ifdef CONFIG_MMC_EMBEDDED_SDIO
 	if (plat->mmc_data.embedded_sdio)
 		mmc_set_embedded_sdio_data(host->mmc,
@@ -247,8 +297,12 @@ static int __devinit sdhci_tegra_probe(struct platform_device *pdev)
 		rc = PTR_ERR(clk);
 		goto err_clk_get;
 	}
-	clk_enable(clk);
+	rc = clk_enable(clk);
+	if (rc != 0)
+		goto err_clk_put;
 	pltfm_host->clk = clk;
+	pltfm_host->priv = tegra_host;
+	tegra_host->clk_enabled = true;
 
 	host->mmc->pm_caps = plat->pm_flags;
 
@@ -267,6 +321,7 @@ static int __devinit sdhci_tegra_probe(struct platform_device *pdev)
 
 err_add_host:
 	clk_disable(pltfm_host->clk);
+err_clk_put:
 	clk_put(pltfm_host->clk);
 err_clk_get:
 	if (gpio_is_valid(plat->wp_gpio)) {
@@ -289,6 +344,7 @@ err_cd_req:
 err_power_req:
 err_no_plat:
 	sdhci_pltfm_free(pdev);
+	kfree(tegra_host);
 	return rc;
 }
 
@@ -296,6 +352,7 @@ static int __devexit sdhci_tegra_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct tegra_sdhci_host *tegra_host = pltfm_host->priv;
 	struct tegra_sdhci_platform_data *plat;
 	int dead = (readl(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff);
 
@@ -319,10 +376,12 @@ static int __devexit sdhci_tegra_remove(struct platform_device *pdev)
 		gpio_free(plat->power_gpio);
 	}
 
-	clk_disable(pltfm_host->clk);
+	if (tegra_host->clk_enabled)
+		clk_disable(pltfm_host->clk);
 	clk_put(pltfm_host->clk);
 
 	sdhci_pltfm_free(pdev);
+	kfree(tegra_host);
 
 	return 0;
 }