SARADC controller needs to be reset before programming it, otherwise
it will not function properly.
Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
Cc: Heiko Stuebner <heiko@xxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: linux-iio@xxxxxxxxxxxxxxx
Cc: linux-rockchip@xxxxxxxxxxxxxxxxxxx
---
.../bindings/iio/adc/rockchip-saradc.txt | 5 +++++
drivers/iio/adc/Kconfig | 1 +
drivers/iio/adc/rockchip_saradc.c | 22 ++++++++++++++++++++++
3 files changed, 28 insertions(+)
diff --git a/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt b/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
index bf99e2f..d2258be 100644
--- a/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
@@ -13,6 +13,9 @@ Required properties:
- clocks: Must contain an entry for each entry in clock-names.
- clock-names: Shall be "saradc" for the converter-clock, and "apb_pclk" for
the peripheral clock.
+- resets: Must contain an entry for each entry in reset-names.
+ See ../reset/reset.txt for details.
+- reset-names: Must include the name "saradc-apb".
- vref-supply: The regulator supply ADC reference voltage.
- #io-channel-cells: Should be 1, see ../iio-bindings.txt
@@ -23,6 +26,8 @@ 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..2f0e110 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 +231,13 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
if (IS_ERR(info->regs))
return PTR_ERR(info->regs);
+ info->reset = devm_reset_control_get(&pdev->dev, "saradc-apb");
+ if (IS_ERR(info->reset)) {
+ ret = PTR_ERR(info->reset);
+ dev_err(&pdev->dev, "failed to get saradc reset: %d\n", ret);
+ return ret;
+ }
+
init_completion(&info->completion);
irq = platform_get_irq(pdev, 0);
@@ -252,6 +272,8 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
return PTR_ERR(info->vref);
}
+ rockchip_saradc_reset_controller(info->reset);
+
/*
* Use a default value for the converter clock.
* This may become user-configurable in the future.
--
1.9.1
--
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