mfd: omap-usb-tll: serialize access to TLL device

Get rid of the unnecessary spin_lock_irqsave/restore() as there is
no interrupt handler for this driver. Instead we serialize access
to tll_dev using a global spinlock.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c
index eccc65e..55c85c7 100644 (file)
--- a/drivers/mfd/omap-usb-tll.c
+++ b/drivers/mfd/omap-usb-tll.c
@@ -103,14 +103,13 @@ struct usbtll_omap {
        int                                     nch;    /* num. of channels */
        struct usbhs_omap_platform_data         *pdata;
        struct clk                              **ch_clk;
-       /* secure the register updates */
-       spinlock_t                              lock;
 };
 
 /*-------------------------------------------------------------------------*/
 
 static const char usbtll_driver_name[] = USBTLL_DRIVER_NAME;
 static struct device   *tll_dev;
+static DEFINE_SPINLOCK(tll_lock);      /* serialize access to tll_dev */
 
 /*-------------------------------------------------------------------------*/
 
@@ -212,7 +211,6 @@ static int usbtll_omap_probe(struct platform_device *pdev)
        struct resource                         *res;
        struct usbtll_omap                      *tll;
        unsigned                                reg;
-       unsigned long                           flags;
        int                                     ret = 0;
        int                                     i, ver;
        bool needs_tll;
@@ -230,8 +228,6 @@ static int usbtll_omap_probe(struct platform_device *pdev)
                return -ENODEV;
        }
 
-       spin_lock_init(&tll->lock);
-
        tll->pdata = pdata;
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -246,8 +242,6 @@ static int usbtll_omap_probe(struct platform_device *pdev)
        pm_runtime_enable(dev);
        pm_runtime_get_sync(dev);
 
-       spin_lock_irqsave(&tll->lock, flags);
-
        ver =  usbtll_read(base, OMAP_USBTLL_REVISION);
        switch (ver) {
        case OMAP_USBTLL_REV1:
@@ -265,8 +259,6 @@ static int usbtll_omap_probe(struct platform_device *pdev)
                break;
        }
 
-       spin_unlock_irqrestore(&tll->lock, flags);
-
        tll->ch_clk = devm_kzalloc(dev, sizeof(struct clk * [tll->nch]),
                                                GFP_KERNEL);
        if (!tll->ch_clk) {
@@ -286,8 +278,6 @@ static int usbtll_omap_probe(struct platform_device *pdev)
                        dev_dbg(dev, "can't get clock : %s\n", clkname);
        }
 
-       spin_lock_irqsave(&tll->lock, flags);
-
        needs_tll = false;
        for (i = 0; i < tll->nch; i++)
                needs_tll |= omap_usb_mode_needs_tll(pdata->port_mode[i]);
@@ -332,10 +322,11 @@ static int usbtll_omap_probe(struct platform_device *pdev)
                }
        }
 
-       spin_unlock_irqrestore(&tll->lock, flags);
        pm_runtime_put_sync(dev);
        /* only after this can omap_tll_enable/disable work */
+       spin_lock(&tll_lock);
        tll_dev = dev;
+       spin_unlock(&tll_lock);
 
        return 0;
 
@@ -357,7 +348,9 @@ static int usbtll_omap_remove(struct platform_device *pdev)
        struct usbtll_omap *tll = platform_get_drvdata(pdev);
        int i;
 
+       spin_lock(&tll_lock);
        tll_dev = NULL;
+       spin_unlock(&tll_lock);
 
        for (i = 0; i < tll->nch; i++)
                if (!IS_ERR(tll->ch_clk[i]))
@@ -371,13 +364,10 @@ static int usbtll_runtime_resume(struct device *dev)
 {
        struct usbtll_omap                      *tll = dev_get_drvdata(dev);
        struct usbhs_omap_platform_data         *pdata = tll->pdata;
-       unsigned long                           flags;
        int i;
 
        dev_dbg(dev, "usbtll_runtime_resume\n");
 
-       spin_lock_irqsave(&tll->lock, flags);
-
        for (i = 0; i < tll->nch; i++) {
                if (omap_usb_mode_needs_tll(pdata->port_mode[i])) {
                        int r;
@@ -393,8 +383,6 @@ static int usbtll_runtime_resume(struct device *dev)
                }
        }
 
-       spin_unlock_irqrestore(&tll->lock, flags);
-
        return 0;
 }
 
@@ -402,13 +390,10 @@ static int usbtll_runtime_suspend(struct device *dev)
 {
        struct usbtll_omap                      *tll = dev_get_drvdata(dev);
        struct usbhs_omap_platform_data         *pdata = tll->pdata;
-       unsigned long                           flags;
        int i;
 
        dev_dbg(dev, "usbtll_runtime_suspend\n");
 
-       spin_lock_irqsave(&tll->lock, flags);
-
        for (i = 0; i < tll->nch; i++) {
                if (omap_usb_mode_needs_tll(pdata->port_mode[i])) {
                        if (!IS_ERR(tll->ch_clk[i]))
@@ -416,8 +401,6 @@ static int usbtll_runtime_suspend(struct device *dev)
                }
        }
 
-       spin_unlock_irqrestore(&tll->lock, flags);
-
        return 0;
 }
 
@@ -439,21 +422,39 @@ static struct platform_driver usbtll_omap_driver = {
 
 int omap_tll_enable(void)
 {
+       int ret;
+
+       spin_lock(&tll_lock);
+
        if (!tll_dev) {
                pr_err("%s: OMAP USB TLL not initialized\n", __func__);
-               return  -ENODEV;
+               ret = -ENODEV;
+       } else {
+               ret = pm_runtime_get_sync(tll_dev);
        }
-       return pm_runtime_get_sync(tll_dev);
+
+       spin_unlock(&tll_lock);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(omap_tll_enable);
 
 int omap_tll_disable(void)
 {
+       int ret;
+
+       spin_lock(&tll_lock);
+
        if (!tll_dev) {
                pr_err("%s: OMAP USB TLL not initialized\n", __func__);
-               return  -ENODEV;
+               ret = -ENODEV;
+       } else {
+               ret = pm_runtime_put_sync(tll_dev);
        }
-       return pm_runtime_put_sync(tll_dev);
+
+       spin_unlock(&tll_lock);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(omap_tll_disable);