From ae35496230bc792fa76505ab7fcee694c7f7d523 Mon Sep 17 00:00:00 2001 From: Naidu Tellapati Date: Thu, 7 May 2015 18:24:02 -0300 Subject: [PATCH] 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: Naidu Tellapati Signed-off-by: Ezequiel Garcia Signed-off-by: Jonathan Cameron --- drivers/iio/adc/cc10001_adc.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/iio/adc/cc10001_adc.c b/drivers/iio/adc/cc10001_adc.c index 115f6e9..8254f52 100644 --- a/drivers/iio/adc/cc10001_adc.c +++ b/drivers/iio/adc/cc10001_adc.c @@ -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; @@ -153,7 +154,8 @@ static irqreturn_t cc10001_adc_trigger_h(int irq, void *p) mutex_lock(&adc_dev->lock); - cc10001_adc_power_up(adc_dev); + if (!adc_dev->shared) + cc10001_adc_power_up(adc_dev); /* Calculate delay step for eoc and sampled data */ delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT; @@ -177,7 +179,8 @@ static irqreturn_t cc10001_adc_trigger_h(int irq, void *p) } done: - cc10001_adc_power_down(adc_dev); + if (!adc_dev->shared) + cc10001_adc_power_down(adc_dev); mutex_unlock(&adc_dev->lock); @@ -196,7 +199,8 @@ static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev, unsigned int delay_ns; u16 val; - cc10001_adc_power_up(adc_dev); + if (!adc_dev->shared) + cc10001_adc_power_up(adc_dev); /* Calculate delay step for eoc and sampled data */ delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT; @@ -205,7 +209,8 @@ static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev, val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns); - cc10001_adc_power_down(adc_dev); + 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); -- 2.7.4