[media] rc: img-ir: Add and enable sys clock for img-ir

Gets a handle to the system clock, already described in the binding
document, and calls the appropriate common clock framework functions
to mark it prepared/enabled, the common clock framework initially
enables the clock and doesn't disable it at least until the
device/driver is removed.
It's important the systen clock is enabled before register interface is
accessed by the driver.
The system clock to IR is needed for the driver to communicate with the
IR hardware via MMIO accesses on the system bus, so it must not be
disabled during use or the driver will malfunction.

Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/rc/img-ir/img-ir-core.c b/drivers/media/rc/img-ir/img-ir-core.c
index 77c78de4f5bf57ab4bb899357815d9d064c69272..a10d66600ce4773afd0f2cbdb1b18fa51b8b0efb 100644 (file)
--- a/drivers/media/rc/img-ir/img-ir-core.c
+++ b/drivers/media/rc/img-ir/img-ir-core.c
@@ -110,16 +110,32 @@ static int img_ir_probe(struct platform_device *pdev)
        priv->clk = devm_clk_get(&pdev->dev, "core");
        if (IS_ERR(priv->clk))
                dev_warn(&pdev->dev, "cannot get core clock resource\n");
+
+       /* Get sys clock */
+       priv->sys_clk = devm_clk_get(&pdev->dev, "sys");
+       if (IS_ERR(priv->sys_clk))
+               dev_warn(&pdev->dev, "cannot get sys clock resource\n");
        /*
-        * The driver doesn't need to know about the system ("sys") or power
-        * modulation ("mod") clocks yet
+        * Enabling the system clock before the register interface is
+        * accessed. ISR shouldn't get called with Sys Clock disabled,
+        * hence exiting probe with an error.
         */
+       if (!IS_ERR(priv->sys_clk)) {
+               error = clk_prepare_enable(priv->sys_clk);
+               if (error) {
+                       dev_err(&pdev->dev, "cannot enable sys clock\n");
+                       return error;
+               }
+       }
 
        /* Set up raw & hw decoder */
        error = img_ir_probe_raw(priv);
        error2 = img_ir_probe_hw(priv);
-       if (error && error2)
-               return (error == -ENODEV) ? error2 : error;
+       if (error && error2) {
+               if (error == -ENODEV)
+                       error = error2;
+               goto err_probe;
+       }
 
        /* Get the IRQ */
        priv->irq = irq;
@@ -139,6 +155,9 @@ static int img_ir_probe(struct platform_device *pdev)
 err_irq:
        img_ir_remove_hw(priv);
        img_ir_remove_raw(priv);
+err_probe:
+       if (!IS_ERR(priv->sys_clk))
+               clk_disable_unprepare(priv->sys_clk);
        return error;
 }
 
@@ -152,6 +171,8 @@ static int img_ir_remove(struct platform_device *pdev)
 
        if (!IS_ERR(priv->clk))
                clk_disable_unprepare(priv->clk);
+       if (!IS_ERR(priv->sys_clk))
+               clk_disable_unprepare(priv->sys_clk);
        return 0;
 }
 

diff --git a/drivers/media/rc/img-ir/img-ir.h b/drivers/media/rc/img-ir/img-ir.h
index 2ddf560831825c98e4548d146ee15d36ad52f0b7..f1387c016d3d27c7969d3bcb345b0f661612bdaf 100644 (file)
--- a/drivers/media/rc/img-ir/img-ir.h
+++ b/drivers/media/rc/img-ir/img-ir.h
@@ -138,6 +138,7 @@ struct clk;
  * @dev:               Platform device.
  * @irq:               IRQ number.
  * @clk:               Input clock.
+ * @sys_clk:           System clock.
  * @reg_base:          Iomem base address of IR register block.
  * @lock:              Protects IR registers and variables in this struct.
  * @raw:               Driver data for raw decoder.
@@ -147,6 +148,7 @@ struct img_ir_priv {
        struct device           *dev;
        int                     irq;
        struct clk              *clk;
+       struct clk              *sys_clk;
        void __iomem            *reg_base;
        spinlock_t              lock;