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iio: adc: rockchip_saradc: reset saradc controller before programming it

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

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>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Caesar Wang 2016-07-27 22:24:04 +08:00 committed by Jonathan Cameron
parent 7ac61a062f
commit 543852af8e
3 changed files with 38 additions and 0 deletions
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7
Documentation/devicetree/bindings/iio/adc/rockchip-saradc.txt
View file

@ -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 = <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>;
};

1
drivers/iio/adc/Kconfig
View file

@ -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.

30
drivers/iio/adc/rockchip_saradc.c
View file

@ -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.