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

From: [email-masked] (Caesar Wang)
Date: Sat, 30 Jul 2016 07:21:45 +0800

On 2016?07?27? 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 <[email-masked]>
>> Cc: Jonathan Cameron <[email-masked]>
>> Cc: Heiko Stuebner <[email-masked]>
>> Cc: Rob Herring <[email-masked]>
>> Cc: linux-iio at vger.kernel.org
>> Cc: linux-rockchip at lists.infradead.org
>> Tested-by: Guenter Roeck <[email-masked]>
>>
>> ---
>>
>> 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 at 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 at rock-chip.com