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.naeem@xxxxxxxxxx>
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.hogan@xxxxxxxxxx>
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;
>
>
Attachment:
signature.asc
Description: OpenPGP digital signature
