[PATCH v1 1/2] iio: adc: ti-ads7951: Allow to use on ACPI platforms

[PATCH v1 1/2] iio: adc: ti-ads7951: Allow to use on ACPI platforms

[Andy Shevchenko]

ACPI enabled platforms do not have a mean of regulators. Instead we use
hard coded voltage value for reference pin. When value is 0 (default) we
fall back to request a regulator.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/adc/ti-ads7950.c | 51 ++++++++++++++++++++++++++++++--------------
 1 file changed, 35 insertions(+), 16 deletions(-)

diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index 16a06633332c..44d2a3692614 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -21,6 +21,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/acpi.h>
 #include <linux/bitops.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -37,6 +38,12 @@
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 
+/*
+ * In case of ACPI, we use the 5000 mV as default for the reference pin.
+ * Device tree users encode that via the vref-supply regulator.
+ */
+#define TI_ADS7950_VA_MV_ACPI_DEFAULT	5000
+
 #define TI_ADS7950_CR_MANUAL	BIT(12)
 #define TI_ADS7950_CR_WRITE	BIT(11)
 #define TI_ADS7950_CR_CHAN(ch)	((ch) << 7)
@@ -58,6 +65,7 @@ struct ti_ads7950_state {
 	struct spi_message	scan_single_msg;
 
 	struct regulator	*reg;
+	unsigned int		vref_mv;
 
 	unsigned int		settings;
 
@@ -305,11 +313,15 @@ static int ti_ads7950_get_range(struct ti_ads7950_state *st)
 {
 	int vref;
 
-	vref = regulator_get_voltage(st->reg);
-	if (vref < 0)
-		return vref;
+	if (st->vref_mv) {
+		vref = st->vref_mv;
+	} else {
+		vref = regulator_get_voltage(st->reg);
+		if (vref < 0)
+			return vref;
 
-	vref /= 1000;
+		vref /= 1000;
+	}
 
 	if (st->settings & TI_ADS7950_CR_RANGE_5V)
 		vref *= 2;
@@ -411,16 +423,20 @@ static int ti_ads7950_probe(struct spi_device *spi)
 	spi_message_init_with_transfers(&st->scan_single_msg,
 					st->scan_single_xfer, 3);
 
-	st->reg = devm_regulator_get(&spi->dev, "vref");
-	if (IS_ERR(st->reg)) {
-		dev_err(&spi->dev, "Failed get get regulator \"vref\"\n");
-		return PTR_ERR(st->reg);
-	}
-
-	ret = regulator_enable(st->reg);
-	if (ret) {
-		dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n");
-		return ret;
+	if (ACPI_COMPANION(&spi->dev)) {
+		st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT;
+	} else {
+		st->reg = devm_regulator_get(&spi->dev, "vref");
+		if (IS_ERR(st->reg)) {
+			dev_err(&spi->dev, "Failed get get regulator \"vref\"\n");
+			return PTR_ERR(st->reg);
+		}
+
+		ret = regulator_enable(st->reg);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n");
+			return ret;
+		}
 	}
 
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
@@ -441,7 +457,8 @@ static int ti_ads7950_probe(struct spi_device *spi)
 error_cleanup_ring:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_disable_reg:
-	regulator_disable(st->reg);
+	if (!st->vref_mv)
+		regulator_disable(st->reg);
 
 	return ret;
 }
@@ -453,7 +470,9 @@ static int ti_ads7950_remove(struct spi_device *spi)
 
 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
-	regulator_disable(st->reg);
+
+	if (!st->vref_mv)
+		regulator_disable(st->reg);
 
 	return 0;
 }
-- 
2.13.2

[PATCH v1 2/2] iio: adc: ti-ads7950: Add OF device ID table

[Andy Shevchenko]

The driver doesn't have a struct of_device_id table but supported devices
are registered via Device Trees. This is working on the assumption that a
SPI device registered via OF will always match a legacy SPI device ID and
that the MODALIAS reported will always be of the form spi:<device>.

There is an ACPI method to enumerate such devices via specific ACPI ID
and use of compatible strings. It will not work for the drivers which
have no OF match ID table present.

Besides this could change in the future so the correct approach is to
have an OF device ID table if the devices are registered via OF.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/adc/ti-ads7950.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index 44d2a3692614..c67f2725c2bb 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -494,9 +494,27 @@ static const struct spi_device_id ti_ads7950_id[] = {
 };
 MODULE_DEVICE_TABLE(spi, ti_ads7950_id);
 
+static const struct of_device_id ads7950_of_table[] = {
+	{ .compatible = "ti,ads7950", .data = &ti_ads7950_chip_info[TI_ADS7950] },
+	{ .compatible = "ti,ads7951", .data = &ti_ads7950_chip_info[TI_ADS7951] },
+	{ .compatible = "ti,ads7952", .data = &ti_ads7950_chip_info[TI_ADS7952] },
+	{ .compatible = "ti,ads7953", .data = &ti_ads7950_chip_info[TI_ADS7953] },
+	{ .compatible = "ti,ads7954", .data = &ti_ads7950_chip_info[TI_ADS7954] },
+	{ .compatible = "ti,ads7955", .data = &ti_ads7950_chip_info[TI_ADS7955] },
+	{ .compatible = "ti,ads7956", .data = &ti_ads7950_chip_info[TI_ADS7956] },
+	{ .compatible = "ti,ads7957", .data = &ti_ads7950_chip_info[TI_ADS7957] },
+	{ .compatible = "ti,ads7958", .data = &ti_ads7950_chip_info[TI_ADS7958] },
+	{ .compatible = "ti,ads7959", .data = &ti_ads7950_chip_info[TI_ADS7959] },
+	{ .compatible = "ti,ads7960", .data = &ti_ads7950_chip_info[TI_ADS7960] },
+	{ .compatible = "ti,ads7961", .data = &ti_ads7950_chip_info[TI_ADS7961] },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ads7950_of_table);
+
 static struct spi_driver ti_ads7950_driver = {
 	.driver = {
 		.name	= "ads7950",
+		.of_match_table = ads7950_of_table,
 	},
 	.probe		= ti_ads7950_probe,
 	.remove		= ti_ads7950_remove,
-- 
2.13.2

Re: [PATCH v1 2/2] iio: adc: ti-ads7950: Add OF device ID table

[David Lechner]

On 07/26/2017 10:59 AM, Andy Shevchenko wrote:
> The driver doesn't have a struct of_device_id table but supported devices
> are registered via Device Trees. This is working on the assumption that a
> SPI device registered via OF will always match a legacy SPI device ID and
> that the MODALIAS reported will always be of the form spi:<device>.
> 
> There is an ACPI method to enumerate such devices via specific ACPI ID
> and use of compatible strings. It will not work for the drivers which
> have no OF match ID table present.
> 
> Besides this could change in the future so the correct approach is to
> have an OF device ID table if the devices are registered via OF.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Works for me.

Tested-by: David Lechner <david@lechnology.com>

Re: [PATCH v1 1/2] iio: adc: ti-ads7951: Allow to use on ACPI platforms

[David Lechner]

On 07/26/2017 10:59 AM, Andy Shevchenko wrote:
> ACPI enabled platforms do not have a mean of regulators. Instead we use
> hard coded voltage value for reference pin. When value is 0 (default) we
> fall back to request a regulator.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

I can't test the ACPI stuff, but I made sure this doesn't break me.

Tested-By: David Lechner <david@lechnology.com>

Re: [PATCH v1 1/2] iio: adc: ti-ads7951: Allow to use on ACPI platforms

[Andy Shevchenko]

On Fri, 2017-07-28 at 15:55 -0500, David Lechner wrote:
> On 07/26/2017 10:59 AM, Andy Shevchenko wrote:
> > ACPI enabled platforms do not have a mean of regulators. Instead we
> > use
> > hard coded voltage value for reference pin. When value is 0
> > (default) we
> > fall back to request a regulator.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> I can't test the ACPI stuff, but I made sure this doesn't break me.
> 
> Tested-By: David Lechner <david@lechnology.com>

Thanks for testing, though I see you noticed v2 of the series.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy