[PATCH v1 07/10] iio:adc:at91-sama5d2: Support backup mode

Romain Izard
2017-09-08T15:36:38Z

Support the backup mode for platform suspend, by restoring the hardware
registers on resume.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
---
drivers/iio/adc/at91-sama5d2_adc.c | 71 ++++++++++++++++++++++++++++++++------
1 file changed, 61 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index e10dca3ed74b..f9718c863363 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -200,6 +200,7 @@ struct at91_adc_state {
u32 conversion_value;
struct at91_adc_soc_info soc_info;
wait_queue_head_t wq_data_available;
+ unsigned int current_rate;
/*
* lock to prevent concurrent 'single conversion' requests through
* sysfs.
@@ -269,6 +270,8 @@ static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
at91_adc_writel(st, AT91_SAMA5D2_MR, mr);

+ st->current_rate = freq;
+
dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
freq, startup, prescal);
}
@@ -375,7 +378,9 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
val > st->soc_info.max_sample_rate)
return -EINVAL;

+ mutex_lock(&st->lock);
at91_adc_setup_samp_freq(st, val);
+ mutex_unlock(&st->lock);

return 0;
}
@@ -386,6 +391,21 @@ static const struct iio_info at91_adc_info = {
.driver_module = THIS_MODULE,
};

+static void at91_adc_init_hw(struct at91_adc_state *st, unsigned int freq)
+{
+ at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
+ at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
+ /*
+ * Transfer field must be set to 2 according to the datasheet and
+ * allows different analog settings for each channel.
+ */
+ at91_adc_writel(st, AT91_SAMA5D2_MR,
+ AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
+
+ at91_adc_setup_samp_freq(st, freq);
+
+}
+
static int at91_adc_probe(struct platform_device *pdev)
{
struct iio_dev *indio_dev;
@@ -482,16 +502,7 @@ static int at91_adc_probe(struct platform_device *pdev)
goto vref_disable;
}

- at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
- at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
- /*
- * Transfer field must be set to 2 according to the datasheet and
- * allows different analog settings for each channel.
- */
- at91_adc_writel(st, AT91_SAMA5D2_MR,
- AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
-
- at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
+ at91_adc_init_hw(st, st->soc_info.min_sample_rate);

ret = clk_prepare_enable(st->per_clk);
if (ret)
@@ -541,12 +552,52 @@ static const struct of_device_id at91_adc_dt_match[] = {
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_match);

+#ifdef CONFIG_PM_SLEEP
+static int at91_adc_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct at91_adc_state *st = iio_priv(indio_dev);
+
+ clk_disable_unprepare(st->per_clk);
+
+ regulator_disable(st->vref);
+ regulator_disable(st->reg);
+
+ return 0;
+}
+
+static int at91_adc_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct at91_adc_state *st = iio_priv(indio_dev);
+ int err;
+
+ err = regulator_enable(st->reg);
+ if (err)
+ return err;
+
+ err = regulator_enable(st->vref);
+ if (err)
+ return err;
+
+ at91_adc_init_hw(st, st->current_rate);
+
+ err = clk_prepare_enable(st->per_clk);
+ return err;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
+
static struct platform_driver at91_adc_driver = {
.probe = at91_adc_probe,
.remove = at91_adc_remove,
.driver = {
.name = "at91-sama5d2_adc",
.of_match_table = at91_adc_dt_match,
+ .pm = &at91_adc_pm_ops,
},
};
module_platform_driver(at91_adc_driver)
--
2.11.0