17 files changed, 97 insertions, 58 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 776d76b8cb69..dc461637e778 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -442,6 +442,7 @@ config ARCH_MXS
         select ARCH_REQUIRE_GPIOLIB
         select CLKDEV_LOOKUP
         select CLKSRC_MMIO
+        select HAVE_CLK_PREPARE
         help
           Support for Freescale MXS-based family of processors
 
diff --git a/arch/arm/mach-mxs/clock-mx23.c b/arch/arm/mach-mxs/clock-mx23.c
index 0163b6d83773..e12e11231dc7 100644
--- a/arch/arm/mach-mxs/clock-mx23.c
+++ b/arch/arm/mach-mxs/clock-mx23.c
@@ -545,11 +545,11 @@ int __init mx23_clocks_init(void)
          */
         clk_set_parent(&ssp_clk, &ref_io_clk);
 
-        clk_enable(&cpu_clk);
-        clk_enable(&hbus_clk);
-        clk_enable(&xbus_clk);
-        clk_enable(&emi_clk);
-        clk_enable(&uart_clk);
+        clk_prepare_enable(&cpu_clk);
+        clk_prepare_enable(&hbus_clk);
+        clk_prepare_enable(&xbus_clk);
+        clk_prepare_enable(&emi_clk);
+        clk_prepare_enable(&uart_clk);
 
         clkdev_add_table(lookups, ARRAY_SIZE(lookups));
 
diff --git a/arch/arm/mach-mxs/clock-mx28.c b/arch/arm/mach-mxs/clock-mx28.c
index da6e4aad177c..f85f1f5b3e1f 100644
--- a/arch/arm/mach-mxs/clock-mx28.c
+++ b/arch/arm/mach-mxs/clock-mx28.c
@@ -775,11 +775,11 @@ int __init mx28_clocks_init(void)
         clk_set_parent(&ssp0_clk, &ref_io0_clk);
         clk_set_parent(&ssp1_clk, &ref_io0_clk);
 
-        clk_enable(&cpu_clk);
-        clk_enable(&hbus_clk);
-        clk_enable(&xbus_clk);
-        clk_enable(&emi_clk);
-        clk_enable(&uart_clk);
+        clk_prepare_enable(&cpu_clk);
+        clk_prepare_enable(&hbus_clk);
+        clk_prepare_enable(&xbus_clk);
+        clk_prepare_enable(&emi_clk);
+        clk_prepare_enable(&uart_clk);
 
         clk_set_parent(&lcdif_clk, &ref_pix_clk);
         clk_set_parent(&saif0_clk, &pll0_clk);
diff --git a/arch/arm/mach-mxs/clock.c b/arch/arm/mach-mxs/clock.c
index a7093c88e6a6..97a6f4acc6cc 100644
--- a/arch/arm/mach-mxs/clock.c
+++ b/arch/arm/mach-mxs/clock.c
@@ -74,10 +74,15 @@ static int __clk_enable(struct clk *clk)
         return 0;
 }
 
-/* This function increments the reference count on the clock and enables the
- * clock if not already enabled. The parent clock tree is recursively enabled
+/*
+ * The clk_enable/clk_disable could be called by drivers in atomic context,
+ * so they should not really hold mutex.  Instead, clk_prepare/clk_unprepare
+ * can hold a mutex, as the pair will only be called in non-atomic context.
+ * Before migrating to common clk framework, we can have __clk_enable and
+ * __clk_disable called in clk_prepare/clk_unprepare with mutex held and
+ * leave clk_enable/clk_disable as the dummy functions.
  */
-int clk_enable(struct clk *clk)
+int clk_prepare(struct clk *clk)
 {
         int ret = 0;
 
@@ -90,13 +95,9 @@ int clk_enable(struct clk *clk)
 
         return ret;
 }
-EXPORT_SYMBOL(clk_enable);
+EXPORT_SYMBOL(clk_prepare);
 
-/* This function decrements the reference count on the clock and disables
- * the clock when reference count is 0. The parent clock tree is
- * recursively disabled
- */
-void clk_disable(struct clk *clk)
+void clk_unprepare(struct clk *clk)
 {
         if (clk == NULL || IS_ERR(clk))
                 return;
@@ -105,6 +106,18 @@ void clk_disable(struct clk *clk)
         __clk_disable(clk);
         mutex_unlock(&clocks_mutex);
 }
+EXPORT_SYMBOL(clk_unprepare);
+
+int clk_enable(struct clk *clk)
+{
+        return 0;
+}
+EXPORT_SYMBOL(clk_enable);
+
+void clk_disable(struct clk *clk)
+{
+        /* nothing to do */
+}
 EXPORT_SYMBOL(clk_disable);
 
 /* Retrieve the *current* clock rate. If the clock itself
@@ -166,7 +179,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
                 return ret;
 
         if (clk->usecount)
-                clk_enable(parent);
+                clk_prepare_enable(parent);
 
         mutex_lock(&clocks_mutex);
         ret = clk->set_parent(clk, parent);
diff --git a/arch/arm/mach-mxs/mach-mx28evk.c b/arch/arm/mach-mxs/mach-mx28evk.c
index 064ec5abaa55..6b9e83e6e893 100644
--- a/arch/arm/mach-mxs/mach-mx28evk.c
+++ b/arch/arm/mach-mxs/mach-mx28evk.c
@@ -228,7 +228,7 @@ static void __init mx28evk_fec_reset(void)
         /* Enable fec phy clock */
         clk = clk_get_sys("pll2", NULL);
         if (!IS_ERR(clk))
-                clk_enable(clk);
+                clk_prepare_enable(clk);
 
         /* Power up fec phy */
         ret = gpio_request(MX28EVK_FEC_PHY_POWER, "fec-phy-power");
diff --git a/arch/arm/mach-mxs/system.c b/arch/arm/mach-mxs/system.c
index 20ec3bddf7cd..9760a1285e0d 100644
--- a/arch/arm/mach-mxs/system.c
+++ b/arch/arm/mach-mxs/system.c
@@ -66,7 +66,7 @@ static int __init mxs_arch_reset_init(void)
 
         clk = clk_get_sys("rtc", NULL);
         if (!IS_ERR(clk))
-                clk_enable(clk);
+                clk_prepare_enable(clk);
 
         return 0;
 }
diff --git a/arch/arm/mach-mxs/timer.c b/arch/arm/mach-mxs/timer.c
index cace0d2e5a55..564a63279f18 100644
--- a/arch/arm/mach-mxs/timer.c
+++ b/arch/arm/mach-mxs/timer.c
@@ -245,7 +245,7 @@ static int __init mxs_clocksource_init(struct clk *timer_clk)
 
 void __init mxs_timer_init(struct clk *timer_clk, int irq)
 {
-        clk_enable(timer_clk);
+        clk_prepare_enable(timer_clk);
 
         /*
          * Initialize timers to a known state
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 35309274ad68..9b3cd08cd0ed 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -3,5 +3,8 @@ config CLKDEV_LOOKUP
         bool
         select HAVE_CLK
 
+config HAVE_CLK_PREPARE
+        bool
+
 config HAVE_MACH_CLKDEV
         bool
diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index b4588bdd98bb..fc903c0ed234 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -334,7 +334,7 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
                         goto err_irq;
         }
 
-        ret = clk_enable(mxs_dma->clk);
+        ret = clk_prepare_enable(mxs_dma->clk);
         if (ret)
                 goto err_clk;
 
@@ -372,7 +372,7 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
         dma_free_coherent(mxs_dma->dma_device.dev, PAGE_SIZE,
                         mxs_chan->ccw, mxs_chan->ccw_phys);
 
-        clk_disable(mxs_dma->clk);
+        clk_disable_unprepare(mxs_dma->clk);
 }
 
 static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
@@ -578,7 +578,7 @@ static int __init mxs_dma_init(struct mxs_dma_engine *mxs_dma)
 {
         int ret;
 
-        ret = clk_enable(mxs_dma->clk);
+        ret = clk_prepare_enable(mxs_dma->clk);
         if (ret)
                 goto err_out;
 
@@ -604,7 +604,7 @@ static int __init mxs_dma_init(struct mxs_dma_engine *mxs_dma)
         writel(MXS_DMA_CHANNELS_MASK << MXS_DMA_CHANNELS,
                 mxs_dma->base + HW_APBHX_CTRL1 + MXS_SET_ADDR);
 
-        clk_disable(mxs_dma->clk);
+        clk_disable_unprepare(mxs_dma->clk);
 
         return 0;
 
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index 99b449d26a4d..973011f9a298 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -713,7 +713,7 @@ static int mxs_mmc_probe(struct platform_device *pdev)
                 ret = PTR_ERR(host->clk);
                 goto out_iounmap;
         }
-        clk_enable(host->clk);
+        clk_prepare_enable(host->clk);
 
         mxs_mmc_reset(host);
 
@@ -772,7 +772,7 @@ out_free_dma:
         if (host->dmach)
                 dma_release_channel(host->dmach);
 out_clk_put:
-        clk_disable(host->clk);
+        clk_disable_unprepare(host->clk);
         clk_put(host->clk);
 out_iounmap:
         iounmap(host->base);
@@ -798,7 +798,7 @@ static int mxs_mmc_remove(struct platform_device *pdev)
         if (host->dmach)
                 dma_release_channel(host->dmach);
 
-        clk_disable(host->clk);
+        clk_disable_unprepare(host->clk);
         clk_put(host->clk);
 
         iounmap(host->base);
@@ -819,7 +819,7 @@ static int mxs_mmc_suspend(struct device *dev)
 
         ret = mmc_suspend_host(mmc);
 
-        clk_disable(host->clk);
+        clk_disable_unprepare(host->clk);
 
         return ret;
 }
@@ -830,7 +830,7 @@ static int mxs_mmc_resume(struct device *dev)
         struct mxs_mmc_host *host = mmc_priv(mmc);
         int ret = 0;
 
-        clk_enable(host->clk);
+        clk_prepare_enable(host->clk);
 
         ret = mmc_resume_host(mmc);
 
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
index de4db7604a3f..2a56fc6f399a 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -126,7 +126,7 @@ int gpmi_init(struct gpmi_nand_data *this)
         struct resources *r = &this->resources;
         int ret;
 
-        ret = clk_enable(r->clock);
+        ret = clk_prepare_enable(r->clock);
         if (ret)
                 goto err_out;
         ret = gpmi_reset_block(r->gpmi_regs, false);
@@ -146,7 +146,7 @@ int gpmi_init(struct gpmi_nand_data *this)
         /* Select BCH ECC. */
         writel(BM_GPMI_CTRL1_BCH_MODE, r->gpmi_regs + HW_GPMI_CTRL1_SET);
 
-        clk_disable(r->clock);
+        clk_disable_unprepare(r->clock);
         return 0;
 err_out:
         return ret;
@@ -202,7 +202,7 @@ int bch_set_geometry(struct gpmi_nand_data *this)
         ecc_strength  = bch_geo->ecc_strength >> 1;
         page_size     = bch_geo->page_size;
 
-        ret = clk_enable(r->clock);
+        ret = clk_prepare_enable(r->clock);
         if (ret)
                 goto err_out;
 
@@ -229,7 +229,7 @@ int bch_set_geometry(struct gpmi_nand_data *this)
         writel(BM_BCH_CTRL_COMPLETE_IRQ_EN,
                                 r->bch_regs + HW_BCH_CTRL_SET);
 
-        clk_disable(r->clock);
+        clk_disable_unprepare(r->clock);
         return 0;
 err_out:
         return ret;
@@ -704,7 +704,7 @@ void gpmi_begin(struct gpmi_nand_data *this)
         int ret;
 
         /* Enable the clock. */
-        ret = clk_enable(r->clock);
+        ret = clk_prepare_enable(r->clock);
         if (ret) {
                 pr_err("We failed in enable the clk\n");
                 goto err_out;
@@ -773,7 +773,7 @@ err_out:
 void gpmi_end(struct gpmi_nand_data *this)
 {
         struct resources *r = &this->resources;
-        clk_disable(r->clock);
+        clk_disable_unprepare(r->clock);
 }
 
 /* Clears a BCH interrupt. */
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index e02337953f41..fdd0f3fbeabb 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -802,7 +802,7 @@ static int flexcan_open(struct net_device *dev)
         struct flexcan_priv *priv = netdev_priv(dev);
         int err;
 
-        clk_enable(priv->clk);
+        clk_prepare_enable(priv->clk);
 
         err = open_candev(dev);
         if (err)
@@ -824,7 +824,7 @@ static int flexcan_open(struct net_device *dev)
  out_close:
         close_candev(dev);
  out:
-        clk_disable(priv->clk);
+        clk_disable_unprepare(priv->clk);
 
         return err;
 }
@@ -838,7 +838,7 @@ static int flexcan_close(struct net_device *dev)
         flexcan_chip_stop(dev);
 
         free_irq(dev->irq, dev);
-        clk_disable(priv->clk);
+        clk_disable_unprepare(priv->clk);
 
         close_candev(dev);
 
@@ -877,7 +877,7 @@ static int __devinit register_flexcandev(struct net_device *dev)
         struct flexcan_regs __iomem *regs = priv->base;
         u32 reg, err;
 
-        clk_enable(priv->clk);
+        clk_prepare_enable(priv->clk);
 
         /* select "bus clock", chip must be disabled */
         flexcan_chip_disable(priv);
@@ -911,7 +911,7 @@ static int __devinit register_flexcandev(struct net_device *dev)
  out:
         /* disable core and turn off clocks */
         flexcan_chip_disable(priv);
-        clk_disable(priv->clk);
+        clk_disable_unprepare(priv->clk);
 
         return err;
 }
diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
index c136230d50bb..112af9b056dc 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -1591,7 +1591,7 @@ fec_probe(struct platform_device *pdev)
                 ret = PTR_ERR(fep->clk);
                 goto failed_clk;
         }
-        clk_enable(fep->clk);
+        clk_prepare_enable(fep->clk);
 
         ret = fec_enet_init(ndev);
         if (ret)
@@ -1614,7 +1614,7 @@ failed_register:
         fec_enet_mii_remove(fep);
 failed_mii_init:
 failed_init:
-        clk_disable(fep->clk);
+        clk_disable_unprepare(fep->clk);
         clk_put(fep->clk);
 failed_clk:
         for (i = 0; i < FEC_IRQ_NUM; i++) {
@@ -1641,7 +1641,7 @@ fec_drv_remove(struct platform_device *pdev)
 
         fec_stop(ndev);
         fec_enet_mii_remove(fep);
-        clk_disable(fep->clk);
+        clk_disable_unprepare(fep->clk);
         clk_put(fep->clk);
         iounmap(fep->hwp);
         unregister_netdev(ndev);
@@ -1667,7 +1667,7 @@ fec_suspend(struct device *dev)
                 fec_stop(ndev);
                 netif_device_detach(ndev);
         }
-        clk_disable(fep->clk);
+        clk_disable_unprepare(fep->clk);
 
         return 0;
 }
@@ -1678,7 +1678,7 @@ fec_resume(struct device *dev)
         struct net_device *ndev = dev_get_drvdata(dev);
         struct fec_enet_private *fep = netdev_priv(ndev);
 
-        clk_enable(fep->clk);
+        clk_prepare_enable(fep->clk);
         if (netif_running(ndev)) {
                 fec_restart(ndev, fep->full_duplex);
                 netif_device_attach(ndev);
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 7e02c9c344fe..c33500a5e032 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -424,7 +424,7 @@ static int mxs_auart_startup(struct uart_port *u)
 {
         struct mxs_auart_port *s = to_auart_port(u);
 
-        clk_enable(s->clk);
+        clk_prepare_enable(s->clk);
 
         writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);
 
@@ -453,7 +453,7 @@ static void mxs_auart_shutdown(struct uart_port *u)
         writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
                         u->membase + AUART_INTR_CLR);
 
-        clk_disable(s->clk);
+        clk_disable_unprepare(s->clk);
 }
 
 static unsigned int mxs_auart_tx_empty(struct uart_port *u)
@@ -634,7 +634,7 @@ auart_console_setup(struct console *co, char *options)
         if (!s)
                 return -ENODEV;
 
-        clk_enable(s->clk);
+        clk_prepare_enable(s->clk);
 
         if (options)
                 uart_parse_options(options, &baud, &parity, &bits, &flow);
@@ -643,7 +643,7 @@ auart_console_setup(struct console *co, char *options)
 
         ret = uart_set_options(&s->port, co, baud, parity, bits, flow);
 
-        clk_disable(s->clk);
+        clk_disable_unprepare(s->clk);
 
         return ret;
 }
diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index d837d63c456f..eb3c5eea1a0f 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -328,7 +328,7 @@ static void mxsfb_enable_controller(struct fb_info *fb_info)
 
         dev_dbg(&host->pdev->dev, "%s\n", __func__);
 
-        clk_enable(host->clk);
+        clk_prepare_enable(host->clk);
         clk_set_rate(host->clk, PICOS2KHZ(fb_info->var.pixclock) * 1000U);
 
         /* if it was disabled, re-enable the mode again */
@@ -368,7 +368,7 @@ static void mxsfb_disable_controller(struct fb_info *fb_info)
 
         writel(VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4 + REG_CLR);
 
-        clk_disable(host->clk);
+        clk_disable_unprepare(host->clk);
 
         host->enabled = 0;
 }
@@ -668,7 +668,7 @@ static int __devinit mxsfb_restore_mode(struct mxsfb_info *host)
         line_count = fb_info->fix.smem_len / fb_info->fix.line_length;
         fb_info->fix.ypanstep = 1;
 
-        clk_enable(host->clk);
+        clk_prepare_enable(host->clk);
         host->enabled = 1;
 
         return 0;
@@ -841,7 +841,7 @@ static int __devinit mxsfb_probe(struct platform_device *pdev)
 
 error_register:
         if (host->enabled)
-                clk_disable(host->clk);
+                clk_disable_unprepare(host->clk);
         fb_destroy_modelist(&fb_info->modelist);
 error_init_fb:
         kfree(fb_info->pseudo_palette);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 7213b52b2c0e..b9d46fa154b4 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -107,6 +107,28 @@ static inline void clk_unprepare(struct clk *clk)
 }
 #endif
 
+/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
+static inline int clk_prepare_enable(struct clk *clk)
+{
+        int ret;
+
+        ret = clk_prepare(clk);
+        if (ret)
+                return ret;
+        ret = clk_enable(clk);
+        if (ret)
+                clk_unprepare(clk);
+
+        return ret;
+}
+
+/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
+static inline void clk_disable_unprepare(struct clk *clk)
+{
+        clk_disable(clk);
+        clk_unprepare(clk);
+}
+
 /**
  * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
  *                This is only valid once the clock source has been enabled.
diff --git a/sound/soc/mxs/mxs-saif.c b/sound/soc/mxs/mxs-saif.c
index 76dc74d24fc2..ef1abb53af95 100644
--- a/sound/soc/mxs/mxs-saif.c
+++ b/sound/soc/mxs/mxs-saif.c
@@ -210,7 +210,7 @@ int mxs_saif_put_mclk(unsigned int saif_id)
                 return -EBUSY;
         }
 
-        clk_disable(saif->clk);
+        clk_disable_unprepare(saif->clk);
 
         /* disable MCLK output */
         __raw_writel(BM_SAIF_CTRL_CLKGATE,
@@ -264,7 +264,7 @@ int mxs_saif_get_mclk(unsigned int saif_id, unsigned int mclk,
         if (ret)
                 return ret;
 
-        ret = clk_enable(saif->clk);
+        ret = clk_prepare_enable(saif->clk);
         if (ret)
                 return ret;