From 543852af8e5902aee8f7c72c89e1513663e0f696 Mon Sep 17 00:00:00 2001 From: Caesar Wang Date: Wed, 27 Jul 2016 22:24:04 +0800 Subject: [PATCH] iio: adc: rockchip_saradc: reset saradc controller before programming it SARADC controller needs to be reset before programming it, otherwise it will not function properly. 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 Cc: Signed-off-by: Jonathan Cameron --- .../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 bf99e2f24788..205593f56fe7 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. +- 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 1de31bdd4ce4..767577298ee3 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 f9ad6c2d6821..85d701291654 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.