[linux-sunxi] [PATCH 1/5] i2c: mv64xxx: Add reset deassert call

[Chen-Yu Tsai]

Hi,

On Fri, Jan 10, 2014 at 1:19 AM, Maxime Ripard
<maxime.ripard at free-electrons.com> wrote:
> The Allwinner A31 SoC using that IP has a reset controller maintaining
> it reset unless told otherwise.
>
> Add some optional reset support to the driver.
>
> Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt | 1 +
>  drivers/i2c/busses/Kconfig                            | 1 +
>  drivers/i2c/busses/i2c-mv64xxx.c                      | 6 ++++++
>  3 files changed, 8 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> index 82e8f6f..603003a 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
> @@ -12,6 +12,7 @@ Optional properties :
>
>   - clock-frequency : Desired I2C bus clock frequency in Hz. If not set the
>  default frequency is 100kHz
> + - resets          : phandle to the parent reset controller
>
>  Examples:
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 3b26129..69aa599 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -528,6 +528,7 @@ config I2C_MPC
>  config I2C_MV64XXX
>         tristate "Marvell mv64xxx I2C Controller"
>         depends on (MV64X60 || PLAT_ORION || ARCH_SUNXI)
> +       select RESET_CONTROLLER
>         help
>           If you say yes to this option, support will be included for the
>           built-in I2C interface on the Marvell 64xxx line of host bridges.
> diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
> index 8be7e42..d4e2f32 100644
> --- a/drivers/i2c/busses/i2c-mv64xxx.c
> +++ b/drivers/i2c/busses/i2c-mv64xxx.c
> @@ -17,6 +17,7 @@
>  #include <linux/interrupt.h>
>  #include <linux/mv643xx_i2c.h>
>  #include <linux/platform_device.h>
> +#include <linux/reset.h>
>  #include <linux/io.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> @@ -743,6 +744,7 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
>  #else
>         const struct of_device_id *device;
>         struct device_node *np = dev->of_node;
> +       struct reset_control *rstc;
>         u32 bus_freq, tclk;
>         int rc = 0;
>
> @@ -763,6 +765,10 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
>         }
>         drv_data->irq = irq_of_parse_and_map(np, 0);
>
> +       rstc = devm_reset_control_get(dev, NULL);
> +       if (!IS_ERR(rstc))
> +               reset_control_deassert(rstc);
> +

Do we need to handle -EPROBE_DEFER here?
Also no reset_control_assert() in the exit path?
I'm asking because I have similar code in my stmmac patches.

Thanks

ChenYu

>         /* Its not yet defined how timeouts will be specified in device tree.
>          * So hard code the value to 1 second.
>          */