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Commit ae354962 authored by Naidu Tellapati's avatar Naidu Tellapati Committed by Jonathan Cameron
Browse files

iio: adc: cc10001: Power-up the ADC at probe time when used remotely 



The ADC is typically shared with remote CPUs not running Linux.
However, there is only one register to power-up/power-down. Remote CPUs
aren't able to power-up the ADC, and rely in Linux doing it instead.

This commit uses the adc-reserved-channels devicetree property to
distinguish shared usage. In this case, the ADC is powered up at
probe time.

If the ADC is used only by the CPU running Linux, power-up/down
at runtime, only when neeeded.

Signed-off-by: default avatarNaidu Tellapati <naidu.tellapati@imgtec.com>
Signed-off-by: default avatarEzequiel Garcia <ezequiel.garcia@imgtec.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent eb2c9ce2

drivers/iio/adc/cc10001_adc.c

+21 −5
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct cc10001_adc_device { 
	struct regulator *reg;

	u16 *buf;



	bool shared;

	struct mutex lock;

	unsigned int start_delay_ns;

	unsigned int eoc_delay_ns;
@@ -153,6 +154,7 @@ static irqreturn_t cc10001_adc_trigger_h(int irq, void *p) 


	mutex_lock(&adc_dev->lock);



	if (!adc_dev->shared)

		cc10001_adc_power_up(adc_dev);



	/* Calculate delay step for eoc and sampled data */
@@ -177,6 +179,7 @@ static irqreturn_t cc10001_adc_trigger_h(int irq, void *p) 
	}



done:

	if (!adc_dev->shared)

		cc10001_adc_power_down(adc_dev);



	mutex_unlock(&adc_dev->lock);
@@ -196,6 +199,7 @@ static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev, 
	unsigned int delay_ns;

	u16 val;



	if (!adc_dev->shared)

		cc10001_adc_power_up(adc_dev);



	/* Calculate delay step for eoc and sampled data */
@@ -205,6 +209,7 @@ static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev, 


	val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns);



	if (!adc_dev->shared)

		cc10001_adc_power_down(adc_dev);



	return val;
@@ -322,8 +327,10 @@ static int cc10001_adc_probe(struct platform_device *pdev) 
	adc_dev = iio_priv(indio_dev);



	channel_map = GENMASK(CC10001_ADC_NUM_CHANNELS - 1, 0);

	if (!of_property_read_u32(node, "adc-reserved-channels", &ret))

	if (!of_property_read_u32(node, "adc-reserved-channels", &ret)) {

		adc_dev->shared = true;

		channel_map &= ~ret;

	}



	adc_dev->reg = devm_regulator_get(&pdev->dev, "vref");

	if (IS_ERR(adc_dev->reg))
@@ -368,6 +375,14 @@ static int cc10001_adc_probe(struct platform_device *pdev) 
	adc_dev->eoc_delay_ns = NSEC_PER_SEC / adc_clk_rate;

	adc_dev->start_delay_ns = adc_dev->eoc_delay_ns * CC10001_WAIT_CYCLES;



	/*

	 * There is only one register to power-up/power-down the AUX ADC.

	 * If the ADC is shared among multiple CPUs, always power it up here.

	 * If the ADC is used only by the MIPS, power-up/power-down at runtime.

	 */

	if (adc_dev->shared)

		cc10001_adc_power_up(adc_dev);



	/* Setup the ADC channels available on the device */

	ret = cc10001_adc_channel_init(indio_dev, channel_map);

	if (ret < 0)
@@ -402,6 +417,7 @@ static int cc10001_adc_remove(struct platform_device *pdev) 
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);

	struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);



	cc10001_adc_power_down(adc_dev);

	iio_device_unregister(indio_dev);

	iio_triggered_buffer_cleanup(indio_dev);

	clk_disable_unprepare(adc_dev->adc_clk);