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>

1 files changed, 27 insertions, 26 deletions

diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c
index eccc65e97202..55c85c78ba44 100644
--- 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);