From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Meerwald-Stadler Subject: Re: [PATCH v3 1/4] iio: adc: rockchip_saradc: reset saradc controller before programming it Date: Wed, 27 Jul 2016 16:47:48 +0200 (CEST) Message-ID: References: <1469629447-544-1-git-send-email-wxt@rock-chips.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <1469629447-544-1-git-send-email-wxt@rock-chips.com> Sender: linux-kernel-owner@vger.kernel.org To: Caesar Wang Cc: jic23@kernel.org, heiko@sntech.de, devicetree@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, dianders@chromium.org, linux-rockchip@lists.infradead.org, robh+dt@kernel.org, john@metanate.com, linux-arm-kernel@lists.infradead.org, linux@roeck-us.net List-Id: devicetree@vger.kernel.org > SARADC controller needs to be reset before programming it, otherwise > it will not function properly. nitpicking on wording below > Signed-off-by: Caesar Wang > Cc: Jonathan Cameron > Cc: Heiko Stuebner > Cc: Rob Herring > Cc: linux-iio@vger.kernel.org > Cc: linux-rockchip@lists.infradead.org > Tested-by: Guenter Roeck > > --- > > 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. > +- reset-names: Must include the name "saradc-apb". > + > Example: > saradc: saradc@2006c000 { > compatible = "rockchip,saradc"; > @@ -23,6 +28,8 @@ Example: > interrupts = ; > 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 > #include > #include > +#include > +#include > #include > #include > > @@ -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. > -- Peter Meerwald-Stadler +43-664-2444418 (mobile)