s3cmci: cpufreq support

Support for cpu frequency changing.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

2 files changed, 96 insertions, 19 deletions

diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index 2af630639910..a73ffb9d7b21 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -13,6 +13,7 @@
 #include <linux/clk.h>
 #include <linux/mmc/host.h>
 #include <linux/platform_device.h>
+#include <linux/cpufreq.h>
 #include <linux/irq.h>
 #include <linux/io.h>
 
@@ -1033,10 +1034,33 @@ static void s3cmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
                 s3cmci_send_request(mmc);
 }
 
+static void s3cmci_set_clk(struct s3cmci_host *host, struct mmc_ios *ios)
+{
+        u32 mci_psc;
+
+        /* Set clock */
+        for (mci_psc = 0; mci_psc < 255; mci_psc++) {
+                host->real_rate = host->clk_rate / (host->clk_div*(mci_psc+1));
+
+                if (host->real_rate <= ios->clock)
+                        break;
+        }
+
+        if (mci_psc > 255)
+                mci_psc = 255;
+
+        host->prescaler = mci_psc;
+        writel(host->prescaler, host->base + S3C2410_SDIPRE);
+
+        /* If requested clock is 0, real_rate will be 0, too */
+        if (ios->clock == 0)
+                host->real_rate = 0;
+}
+
 static void s3cmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
         struct s3cmci_host *host = mmc_priv(mmc);
-        u32 mci_psc, mci_con;
+        u32 mci_con;
 
         /* Set the power state */
 
@@ -1074,23 +1098,7 @@ static void s3cmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                 break;
         }
 
-        /* Set clock */
-        for (mci_psc = 0; mci_psc < 255; mci_psc++) {
-                host->real_rate = host->clk_rate / (host->clk_div*(mci_psc+1));
-
-                if (host->real_rate <= ios->clock)
-                        break;
-        }
-
-        if (mci_psc > 255)
-                mci_psc = 255;
-
-        host->prescaler = mci_psc;
-        writel(host->prescaler, host->base + S3C2410_SDIPRE);
-
-        /* If requested clock is 0, real_rate will be 0, too */
-        if (ios->clock == 0)
-                host->real_rate = 0;
+        s3cmci_set_clk(host, ios);
 
         /* Set CLOCK_ENABLE */
         if (ios->clock)
@@ -1148,6 +1156,61 @@ static struct s3c24xx_mci_pdata s3cmci_def_pdata = {
          * checks. Any zero fields to ensure reaonable defaults are picked. */
 };
 
+#ifdef CONFIG_CPU_FREQ
+
+static int s3cmci_cpufreq_transition(struct notifier_block *nb,
+                                     unsigned long val, void *data)
+{
+        struct s3cmci_host *host;
+        struct mmc_host *mmc;
+        unsigned long newclk;
+        unsigned long flags;
+
+        host = container_of(nb, struct s3cmci_host, freq_transition);
+        newclk = clk_get_rate(host->clk);
+        mmc = host->mmc;
+
+        if ((val == CPUFREQ_PRECHANGE && newclk > host->clk_rate) ||
+            (val == CPUFREQ_POSTCHANGE && newclk < host->clk_rate)) {
+                spin_lock_irqsave(&mmc->lock, flags);
+
+                host->clk_rate = newclk;
+
+                if (mmc->ios.power_mode != MMC_POWER_OFF &&
+                    mmc->ios.clock != 0)
+                        s3cmci_set_clk(host, &mmc->ios);
+
+                spin_unlock_irqrestore(&mmc->lock, flags);
+        }
+
+        return 0;
+}
+
+static inline int s3cmci_cpufreq_register(struct s3cmci_host *host)
+{
+        host->freq_transition.notifier_call = s3cmci_cpufreq_transition;
+
+        return cpufreq_register_notifier(&host->freq_transition,
+                                         CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void s3cmci_cpufreq_deregister(struct s3cmci_host *host)
+{
+        cpufreq_unregister_notifier(&host->freq_transition,
+                                    CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+#else
+static inline int s3cmci_cpufreq_register(struct s3cmci_host *host)
+{
+        return 0;
+}
+
+static inline void s3cmci_cpufreq_deregister(struct s3cmci_host *host)
+{
+}
+#endif
+
 static int __devinit s3cmci_probe(struct platform_device *pdev, int is2440)
 {
         struct s3cmci_host *host;
@@ -1298,10 +1361,16 @@ static int __devinit s3cmci_probe(struct platform_device *pdev, int is2440)
             (host->is2440?"2440":""),
             host->base, host->irq, host->irq_cd, host->dma);
 
+        ret = s3cmci_cpufreq_register(host);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to register cpufreq\n");
+                goto free_dmabuf;
+        }
+
         ret = mmc_add_host(mmc);
         if (ret) {
                 dev_err(&pdev->dev, "failed to add mmc host.\n");
-                goto free_dmabuf;
+                goto free_cpufreq;
         }
 
         platform_set_drvdata(pdev, mmc);
@@ -1309,6 +1378,9 @@ static int __devinit s3cmci_probe(struct platform_device *pdev, int is2440)
 
         return 0;
 
+ free_cpufreq:
+        s3cmci_cpufreq_deregister(host);
+
  free_dmabuf:
         clk_disable(host->clk);
 
@@ -1342,6 +1414,7 @@ static void s3cmci_shutdown(struct platform_device *pdev)
         if (host->irq_cd >= 0)
                 free_irq(host->irq_cd, host);
 
+        s3cmci_cpufreq_deregister(host);
         mmc_remove_host(mmc);
         clk_disable(host->clk);
 }
diff --git a/drivers/mmc/host/s3cmci.h b/drivers/mmc/host/s3cmci.h
index 37d9c60010c9..7e39109587f9 100644
--- a/drivers/mmc/host/s3cmci.h
+++ b/drivers/mmc/host/s3cmci.h
@@ -67,4 +67,8 @@ struct s3cmci_host {
 
         unsigned int            ccnt, dcnt;
         struct tasklet_struct   pio_tasklet;
+
+#ifdef CONFIG_CPU_FREQ
+        struct notifier_block   freq_transition;
+#endif
 };