On 2016?07?27? 22:47, Peter Meerwald-Stadler wrote:

quoted

SARADC controller needs to be reset before programming it, otherwise
it will not function properly.

nitpicking on wording below
  

quoted

Signed-off-by: Caesar Wang <redacted>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-iio at vger.kernel.org
Cc: linux-rockchip at 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

quoted

+- 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