[linux-sunxi] [PATCH v2 04/13] rc: sunxi-cir: Add support for an optional reset controller

[Chen-Yu Tsai]

Hi,

On Thu, Dec 18, 2014 at 1:18 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> On sun6i the cir block is attached to the reset controller, add support
> for de-asserting the reset if a reset controller is specified in dt.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> Acked-by: Mauro Carvalho Chehab <mchehab at osg.samsung.com>
> Acked-by: Maxime Ripard <maxime.ripard at free-electrons.com>
> ---
>  .../devicetree/bindings/media/sunxi-ir.txt         |  2 ++
>  drivers/media/rc/sunxi-cir.c                       | 25 ++++++++++++++++++++--
>  2 files changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/media/sunxi-ir.txt b/Documentation/devicetree/bindings/media/sunxi-ir.txt
> index 23dd5ad..6b70b9b 100644
> --- a/Documentation/devicetree/bindings/media/sunxi-ir.txt
> +++ b/Documentation/devicetree/bindings/media/sunxi-ir.txt
> @@ -10,6 +10,7 @@ Required properties:
>
>  Optional properties:
>  - linux,rc-map-name : Remote control map name.
> +- resets : phandle + reset specifier pair

Should it be optional? Or should we use a sun6i compatible with
a mandatory reset phandle? I mean, the driver/hardware is not
going to work with the reset missing on sun6i.

Seems we are doing it one way for some of our drivers, and
the other (optional) way for more generic ones, like USB.

ChenYu

>  Example:
>
> @@ -17,6 +18,7 @@ ir0: ir at 01c21800 {
>         compatible = "allwinner,sun4i-a10-ir";
>         clocks = <&apb0_gates 6>, <&ir0_clk>;
>         clock-names = "apb", "ir";
> +       resets = <&apb0_rst 1>;
>         interrupts = <0 5 1>;
>         reg = <0x01C21800 0x40>;
>         linux,rc-map-name = "rc-rc6-mce";
> diff --git a/drivers/media/rc/sunxi-cir.c b/drivers/media/rc/sunxi-cir.c
> index 340f7f5..06170e0 100644
> --- a/drivers/media/rc/sunxi-cir.c
> +++ b/drivers/media/rc/sunxi-cir.c
> @@ -23,6 +23,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/module.h>
>  #include <linux/of_platform.h>
> +#include <linux/reset.h>
>  #include <media/rc-core.h>
>
>  #define SUNXI_IR_DEV "sunxi-ir"
> @@ -95,6 +96,7 @@ struct sunxi_ir {
>         int             irq;
>         struct clk      *clk;
>         struct clk      *apb_clk;
> +       struct reset_control *rst;
>         const char      *map_name;
>  };
>
> @@ -166,15 +168,29 @@ static int sunxi_ir_probe(struct platform_device *pdev)
>                 return PTR_ERR(ir->clk);
>         }
>
> +       /* Reset (optional) */
> +       ir->rst = devm_reset_control_get_optional(dev, NULL);
> +       if (IS_ERR(ir->rst)) {
> +               ret = PTR_ERR(ir->rst);
> +               if (ret == -EPROBE_DEFER)
> +                       return ret;
> +               ir->rst = NULL;
> +       } else {
> +               ret = reset_control_deassert(ir->rst);
> +               if (ret)
> +                       return ret;
> +       }
> +
>         ret = clk_set_rate(ir->clk, SUNXI_IR_BASE_CLK);
>         if (ret) {
>                 dev_err(dev, "set ir base clock failed!\n");
> -               return ret;
> +               goto exit_reset_assert;
>         }
>
>         if (clk_prepare_enable(ir->apb_clk)) {
>                 dev_err(dev, "try to enable apb_ir_clk failed\n");
> -               return -EINVAL;
> +               ret = -EINVAL;
> +               goto exit_reset_assert;
>         }
>
>         if (clk_prepare_enable(ir->clk)) {
> @@ -271,6 +287,9 @@ exit_clkdisable_clk:
>         clk_disable_unprepare(ir->clk);
>  exit_clkdisable_apb_clk:
>         clk_disable_unprepare(ir->apb_clk);
> +exit_reset_assert:
> +       if (ir->rst)
> +               reset_control_assert(ir->rst);
>
>         return ret;
>  }
> @@ -282,6 +301,8 @@ static int sunxi_ir_remove(struct platform_device *pdev)
>
>         clk_disable_unprepare(ir->clk);
>         clk_disable_unprepare(ir->apb_clk);
> +       if (ir->rst)
> +               reset_control_assert(ir->rst);
>
>         spin_lock_irqsave(&ir->ir_lock, flags);
>         /* disable IR IRQ */
> --
> 2.1.0
>
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