On 04/02/15 16:48, Sifan Naeem wrote:
> 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.na...@imgtec.com>

Thanks Sifan, looks good to me, doesn't break tz1090, and seems to still
cope with no clocks provided in DT.

Acked-by: James Hogan <james.ho...@imgtec.com>

Cheers
James

> ---
> Changes from v1:
> System clock enabled in probe function before any hardware is accessed.
> Error handling in probe function ensures ISR doesn't get called with 
> system clock disabled.
> 
>  drivers/media/rc/img-ir/img-ir-core.c |   29 +++++++++++++++++++++++++----
>  drivers/media/rc/img-ir/img-ir.h      |    2 ++
>  2 files changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/rc/img-ir/img-ir-core.c 
> b/drivers/media/rc/img-ir/img-ir-core.c
> index 77c78de..a10d666 100644
> --- 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 2ddf560..f1387c0 100644
> --- 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;
>  
> 

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