Re: [PATCH v3 1/4] iio: adc: rockchip_saradc: reset saradc controller before programming it

[Caesar Wang <wxt@xxxxxxxxxxxxxx>]

On 2016年07月27日 22:47, Peter Meerwald-Stadler wrote:
> > SARADC controller needs to be reset before programming it, otherwise
> > it will not function properly.
> nitpicking on wording below
>   
> > Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
> > Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
> > Cc: Heiko Stuebner <heiko@xxxxxxxxx>
> > Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> > Cc: linux-iio@xxxxxxxxxxxxxxx
> > Cc: linux-rockchip@xxxxxxxxxxxxxxxxxxx
> > Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> >
> > ---
> >
> > Changes in v3:
> > - %s/devm_reset_control_get_optional()/devm_reset_control_get()
> > - add Guente's test tag.
> >
> > Changes in v2:
> > - Make the reset as an optional property, since it should work
> > with old devicetrees as well.
> >
> >   .../bindings/iio/adc/rockchip-saradc.txt           |  7 +++++
> >   drivers/iio/adc/Kconfig                            |  1 +
> >   drivers/iio/adc/rockchip_saradc.c                  | 30 ++++++++++++++++++++++
> >   3 files changed, 38 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt b/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
> > index bf99e2f..205593f 100644
> > --- a/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
> > +++ b/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
> > @@ -16,6 +16,11 @@ Required properties:
> >   - vref-supply: The regulator supply ADC reference voltage.
> >   - #io-channel-cells: Should be 1, see ../iio-bindings.txt
> >   
> > +Optional properties:
> > +- resets: Must contain an entry for each entry in reset-names if need support
> > +	  this option. See ../reset/reset.txt for details.
> '... if need support this option.' doesn't sound right, maybe
> simply: '... if needed.' or drop this clause.

I don't plan to resend this series patches.
I'm assuming that Jonathan will help me fix it when ready to apply it.:-)

Glad to resend this series patches if Jonathan boss ask me to do.

Thanks,

Caesar

> > +- reset-names: Must include the name "saradc-apb".
> > +
> >   Example:
> >   	saradc: saradc@2006c000 {
> >   		compatible = "rockchip,saradc";
> > @@ -23,6 +28,8 @@ Example:
> >   		interrupts = <GIC_SPI 26 IRQ_TYPE_LEVEL_HIGH>;
> >   		clocks = <&cru SCLK_SARADC>, <&cru PCLK_SARADC>;
> >   		clock-names = "saradc", "apb_pclk";
> > +		resets = <&cru SRST_SARADC>;
> > +		reset-names = "saradc-apb";
> >   		#io-channel-cells = <1>;
> >   		vref-supply = <&vcc18>;
> >   	};
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 1de31bd..7675772 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -389,6 +389,7 @@ config QCOM_SPMI_VADC
> >   config ROCKCHIP_SARADC
> >   	tristate "Rockchip SARADC driver"
> >   	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
> > +	depends on RESET_CONTROLLER
> >   	help
> >   	  Say yes here to build support for the SARADC found in SoCs from
> >   	  Rockchip.
> > diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
> > index f9ad6c2..85d7012 100644
> > --- a/drivers/iio/adc/rockchip_saradc.c
> > +++ b/drivers/iio/adc/rockchip_saradc.c
> > @@ -21,6 +21,8 @@
> >   #include <linux/of_device.h>
> >   #include <linux/clk.h>
> >   #include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/reset.h>
> >   #include <linux/regulator/consumer.h>
> >   #include <linux/iio/iio.h>
> >   
> > @@ -53,6 +55,7 @@ struct rockchip_saradc {
> >   	struct clk		*clk;
> >   	struct completion	completion;
> >   	struct regulator	*vref;
> > +	struct reset_control	*reset;
> >   	const struct rockchip_saradc_data *data;
> >   	u16			last_val;
> >   };
> > @@ -190,6 +193,16 @@ static const struct of_device_id rockchip_saradc_match[] = {
> >   };
> >   MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
> >   
> > +/**
> > + * Reset SARADC Controller.
> > + */
> > +static void rockchip_saradc_reset_controller(struct reset_control *reset)
> > +{
> > +	reset_control_assert(reset);
> > +	usleep_range(10, 20);
> > +	reset_control_deassert(reset);
> > +}
> > +
> >   static int rockchip_saradc_probe(struct platform_device *pdev)
> >   {
> >   	struct rockchip_saradc *info = NULL;
> > @@ -218,6 +231,20 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
> >   	if (IS_ERR(info->regs))
> >   		return PTR_ERR(info->regs);
> >   
> > +	/*
> > +	 * The reset should be an optional property, as it should work
> > +	 * with old devicetrees as well
> > +	 */
> > +	info->reset = devm_reset_control_get(&pdev->dev, "saradc-apb");
> > +	if (IS_ERR(info->reset)) {
> > +		ret = PTR_ERR(info->reset);
> > +		if (ret != -ENOENT)
> > +			return ret;
> > +
> > +		dev_dbg(&pdev->dev, "no reset control found\n");
> > +		info->reset = NULL;
> > +	}
> > +
> >   	init_completion(&info->completion);
> >   
> >   	irq = platform_get_irq(pdev, 0);
> > @@ -252,6 +279,9 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
> >   		return PTR_ERR(info->vref);
> >   	}
> >   
> > +	if (info->reset)
> > +		rockchip_saradc_reset_controller(info->reset);
> > +
> >   	/*
> >   	 * Use a default value for the converter clock.
> >   	 * This may become user-configurable in the future.


--
caesar wang | software engineer | wxt@xxxxxxxxxxxxx


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