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

Caesar Wang
2016-07-29T23:22:03Z

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@rock-chips.com>
>> Cc: Jonathan Cameron <jic23@kernel.org>
>> Cc: Heiko Stuebner <heiko@sntech.de>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: linux-iio@vger.kernel.org
>> Cc: linux-rockchip@lists.infradead.org
>> Tested-by: Guenter Roeck <linux@roeck-us.net>
>>
>> ---
>>
>> 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@rock-chip.com