Commit edf7550a authored by Joel Stanley's avatar Joel Stanley Committed by Jonathan Cameron
Browse files

iio: adc: aspeed: Deassert reset in probe 



The ASPEED SoC must deassert a reset in order to use the ADC peripheral.

The device tree bindings are updated to document the resets phandle, and
the example is updated to match what is expected for both the reset and
clock phandle. Note that the bindings should have always had the reset
controller, as the hardware is unusable without it.

Signed-off-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 02c5dff5

Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt

+3 −1
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ Required properties: 
- reg: memory window mapping address and length

- clocks: Input clock used to derive the sample clock. Expected to be the

          SoC's APB clock.

- resets: Reset controller phandle

- #io-channel-cells: Must be set to <1> to indicate channels are selected

                     by index.
@@ -15,6 +16,7 @@ Example: 
	adc@1e6e9000 {

		compatible = "aspeed,ast2400-adc";

		reg = <0x1e6e9000 0xb0>;

		clocks = <&clk_apb>;

		clocks = <&syscon ASPEED_CLK_APB>;

		resets = <&syscon ASPEED_RESET_ADC>;

		#io-channel-cells = <1>;

	};

drivers/iio/adc/aspeed_adc.c

+19 −6
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/module.h>

#include <linux/of_platform.h>

#include <linux/platform_device.h>

#include <linux/reset.h>

#include <linux/spinlock.h>

#include <linux/types.h>
@@ -58,6 +59,7 @@ struct aspeed_adc_data { 
	spinlock_t		clk_lock;

	struct clk_hw		*clk_prescaler;

	struct clk_hw		*clk_scaler;

	struct reset_control	*rst;

};



#define ASPEED_CHAN(_idx, _data_reg_addr) {			\
@@ -217,6 +219,15 @@ static int aspeed_adc_probe(struct platform_device *pdev) 
		goto scaler_error;

	}



	data->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);

	if (IS_ERR(data->rst)) {

		dev_err(&pdev->dev,

			"invalid or missing reset controller device tree entry");

		ret = PTR_ERR(data->rst);

		goto reset_error;

	}

	reset_control_deassert(data->rst);



	model_data = of_device_get_match_data(&pdev->dev);



	if (model_data->wait_init_sequence) {
@@ -263,9 +274,10 @@ iio_register_error: 
	writel(ASPEED_OPERATION_MODE_POWER_DOWN,

		data->base + ASPEED_REG_ENGINE_CONTROL);

	clk_disable_unprepare(data->clk_scaler->clk);

reset_error:

	reset_control_assert(data->rst);

clk_enable_error:

	clk_hw_unregister_divider(data->clk_scaler);



scaler_error:

	clk_hw_unregister_divider(data->clk_prescaler);

	return ret;
@@ -280,6 +292,7 @@ static int aspeed_adc_remove(struct platform_device *pdev) 
	writel(ASPEED_OPERATION_MODE_POWER_DOWN,

		data->base + ASPEED_REG_ENGINE_CONTROL);

	clk_disable_unprepare(data->clk_scaler->clk);

	reset_control_assert(data->rst);

	clk_hw_unregister_divider(data->clk_scaler);

	clk_hw_unregister_divider(data->clk_prescaler);

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