davinci: mmc: add cpufreq support

Add cpufreq support to MMC driver. The clock divider value has to be
modified according to the controller input frequency.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Cc: Linus Walleij <linus.ml.walleij@gmail.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/mmc/host/davinci_mmc.c

@@ -25,6 +25,7 @@
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/err.h>
+#include <linux/cpufreq.h>
 #include <linux/mmc/host.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -200,6 +201,9 @@ struct mmc_davinci_host {
 	u8 version;
 	/* for ns in one cycle calculation */
 	unsigned ns_in_one_cycle;
+#ifdef CONFIG_CPU_FREQ
+	struct notifier_block	freq_transition;
+#endif
 };
 
 
@@ -739,27 +743,12 @@ static unsigned int calculate_freq_for_card(struct mmc_davinci_host *host,
 	return mmc_push_pull_divisor;
 }
 
-static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+static void calculate_clk_divider(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	unsigned int open_drain_freq = 0, mmc_pclk = 0;
 	unsigned int mmc_push_pull_freq = 0;
 	struct mmc_davinci_host *host = mmc_priv(mmc);
 
-	mmc_pclk = host->mmc_input_clk;
-	dev_dbg(mmc_dev(host->mmc),
-		"clock %dHz busmode %d powermode %d Vdd %04x\n",
-		ios->clock, ios->bus_mode, ios->power_mode,
-		ios->vdd);
-	if (ios->bus_width == MMC_BUS_WIDTH_4) {
-		dev_dbg(mmc_dev(host->mmc), "Enabling 4 bit mode\n");
-		writel(readl(host->base + DAVINCI_MMCCTL) | MMCCTL_WIDTH_4_BIT,
-			host->base + DAVINCI_MMCCTL);
-	} else {
-		dev_dbg(mmc_dev(host->mmc), "Disabling 4 bit mode\n");
-		writel(readl(host->base + DAVINCI_MMCCTL) & ~MMCCTL_WIDTH_4_BIT,
-			host->base + DAVINCI_MMCCTL);
-	}
-
 	if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN) {
 		u32 temp;
 
@@ -798,6 +787,29 @@ static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 		udelay(10);
 	}
+}
+
+static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	unsigned int mmc_pclk = 0;
+	struct mmc_davinci_host *host = mmc_priv(mmc);
+
+	mmc_pclk = host->mmc_input_clk;
+	dev_dbg(mmc_dev(host->mmc),
+		"clock %dHz busmode %d powermode %d Vdd %04x\n",
+		ios->clock, ios->bus_mode, ios->power_mode,
+		ios->vdd);
+	if (ios->bus_width == MMC_BUS_WIDTH_4) {
+		dev_dbg(mmc_dev(host->mmc), "Enabling 4 bit mode\n");
+		writel(readl(host->base + DAVINCI_MMCCTL) | MMCCTL_WIDTH_4_BIT,
+			host->base + DAVINCI_MMCCTL);
+	} else {
+		dev_dbg(mmc_dev(host->mmc), "Disabling 4 bit mode\n");
+		writel(readl(host->base + DAVINCI_MMCCTL) & ~MMCCTL_WIDTH_4_BIT,
+			host->base + DAVINCI_MMCCTL);
+	}
+
+	calculate_clk_divider(mmc, ios);
 
 	host->bus_mode = ios->bus_mode;
 	if (ios->power_mode == MMC_POWER_UP) {
@@ -1040,6 +1052,52 @@ static struct mmc_host_ops mmc_davinci_ops = {
 
 /*----------------------------------------------------------------------*/
 
+#ifdef CONFIG_CPU_FREQ
+static int mmc_davinci_cpufreq_transition(struct notifier_block *nb,
+				     unsigned long val, void *data)
+{
+	struct mmc_davinci_host *host;
+	unsigned int mmc_pclk;
+	struct mmc_host *mmc;
+	unsigned long flags;
+
+	host = container_of(nb, struct mmc_davinci_host, freq_transition);
+	mmc = host->mmc;
+	mmc_pclk = clk_get_rate(host->clk);
+
+	if (val == CPUFREQ_POSTCHANGE) {
+		spin_lock_irqsave(&mmc->lock, flags);
+		host->mmc_input_clk = mmc_pclk;
+		calculate_clk_divider(mmc, &mmc->ios);
+		spin_unlock_irqrestore(&mmc->lock, flags);
+	}
+
+	return 0;
+}
+
+static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
+{
+	host->freq_transition.notifier_call = mmc_davinci_cpufreq_transition;
+
+	return cpufreq_register_notifier(&host->freq_transition,
+					 CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
+{
+	cpufreq_unregister_notifier(&host->freq_transition,
+				    CPUFREQ_TRANSITION_NOTIFIER);
+}
+#else
+static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
+{
+	return 0;
+}
+
+static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
+{
+}
+#endif
 static void __init init_mmcsd_host(struct mmc_davinci_host *host)
 {
 	/* DAT line portion is diabled and in reset state */
@@ -1169,6 +1227,12 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, host);
 
+	ret = mmc_davinci_cpufreq_register(host);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register cpufreq\n");
+		goto cpu_freq_fail;
+	}
+
 	ret = mmc_add_host(mmc);
 	if (ret < 0)
 		goto out;
@@ -1186,6 +1250,8 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
 	return 0;
 
 out:
+	mmc_davinci_cpufreq_deregister(host);
+cpu_freq_fail:
 	if (host) {
 		davinci_release_dma_channels(host);
 
@@ -1215,6 +1281,8 @@ static int __exit davinci_mmcsd_remove(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, NULL);
 	if (host) {
+		mmc_davinci_cpufreq_deregister(host);
+
 		mmc_remove_host(host->mmc);
 		free_irq(host->irq, host);