On 07/05/15 17:24, Ezequiel Garcia wrote:
> From: Naidu Tellapati <naidu.tellapati@xxxxxxxxxx>
>
> 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 <naidu.tellapati@xxxxxxxxxx>
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxx>
Seems sensible to me, but as you observe it's not a fix as such, so
will hold this until the other patches have propagated through to
the togreg tree.
Feel free to remind me if I seem to have forgotten!
Jonathan
> ---
> 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 10c734d..7d1b2ae 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;
> @@ -155,7 +156,8 @@ 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;
> @@ -179,7 +181,8 @@ 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);
>
> @@ -198,7 +201,8 @@ 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;
> @@ -207,7 +211,8 @@ 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;
> }
> @@ -324,8 +329,10 @@ 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))
> @@ -370,6 +377,14 @@ 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)
> @@ -404,6 +419,7 @@ 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);
>
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