Add support for adc101c* and adc121c*

These chips has an almost identical interface but a deal with a different number of value bits. Datasheet links for comparison:

* http://www.ti.com/lit/ds/symlink/adc081c021.pdf
* http://www.ti.com/lit/ds/symlink/adc101c021.pdf
* http://www.ti.com/lit/ds/symlink/adc121c021.pdf

Signed-off-by Crestez Dan Leonard <[email protected]>

---
 drivers/iio/adc/Kconfig      |  6 +++---
 drivers/iio/adc/ti-adc081c.c | 42 ++++++++++++++++++++++++++++++++++++++----
 2 files changed, 41 insertions(+), 7 deletions(-)

drivers/iio/adc/Kconfig +3 -3

index 9ddcd5d..a2d0db5 100644
@@ -378,11 +378,11 @@ config ROCKCHIP_SARADC
 	  module will be called rockchip_saradc.
 
 config TI_ADC081C
-	tristate "Texas Instruments ADC081C021/027"
+	tristate "Texas Instruments ADC081C/ADC101C/ADC121C family"
 	depends on I2C
 	help
-	  If you say yes here you get support for Texas Instruments ADC081C021
-	  and ADC081C027 ADC chips.
+	  If you say yes here you get support for Texas Instruments ADC081C,
+	  ADC101C and ADC121C ADC chips.
 
 	  This driver can also be built as a module. If so, the module will be
 	  called ti-adc081c.

drivers/iio/adc/ti-adc081c.c +19 -2

index ecbc121..3b3c656 100644
@@ -1,9 +1,21 @@
 /*
+ * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver
+ *
  * Copyright (C) 2012 Avionic Design GmbH
+ * Copyright (C) 2016 Intel
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
+ *
+ * Datasheets:
+ *	http://www.ti.com/lit/ds/symlink/adc081c021.pdf
+ *	http://www.ti.com/lit/ds/symlink/adc101c021.pdf
+ *	http://www.ti.com/lit/ds/symlink/adc121c021.pdf
+ *
+ * The devices have a very similar interface and differ mostly in the number of
+ * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2
+ * bits of value registers are reserved.
  */
 
 #include <linux/err.h>

@@ -17,6 +29,9 @@
 struct adc081c {
 	struct i2c_client *i2c;
 	struct regulator *ref;
+
+	/* 8, 10 or 12 */
+	int bits;
 };
 
 #define REG_CONV_RES 0x00

@@ -34,7 +49,7 @@ static int adc081c_read_raw(struct iio_dev *iio,
 		if (err < 0)
 			return err;
 
-		*value = (err >> 4) & 0xff;
+		*value = (err & 0xFFF) >> (12 - adc->bits);
 		return IIO_VAL_INT;
 
 	case IIO_CHAN_INFO_SCALE:

@@ -43,7 +58,7 @@ static int adc081c_read_raw(struct iio_dev *iio,
 			return err;
 
 		*value = err / 1000;
-		*shift = 8;
+		*shift = adc->bits;
 
 		return IIO_VAL_FRACTIONAL_LOG2;
 

@@ -60,6 +75,19 @@ static const struct iio_chan_spec adc081c_channel = {
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 };
 
+struct adcxx1c_model {
+	int bits;

drivers/iio/adc/ti-adc081c.c +3 -0

+
 static const struct iio_info adc081c_info = {
 	.read_raw = adc081c_read_raw,
 	.driver_module = THIS_MODULE,

@@ -70,6 +98,7 @@ static int adc081c_probe(struct i2c_client *client,
 {
 	struct iio_dev *iio;
 	struct adc081c *adc;
+	struct adcxx1c_model *model = (struct adcxx1c_model*)id->driver_data;
 	int err;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))

@@ -81,6 +110,7 @@ static int adc081c_probe(struct i2c_client *client,
 
 	adc = iio_priv(iio);
 	adc->i2c = client;
+	adc->bits = model->bits;
 
 	adc->ref = devm_regulator_get(&client->dev, "vref");
 	if (IS_ERR(adc->ref))

drivers/iio/adc/ti-adc081c.c +3 -1

 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, adc081c_id);

@@ -132,6 +164,8 @@ MODULE_DEVICE_TABLE(i2c, adc081c_id);
 #ifdef CONFIG_OF
 static const struct of_device_id adc081c_of_match[] = {
 	{ .compatible = "ti,adc081c" },
+	{ .compatible = "ti,adc101c" },
+	{ .compatible = "ti,adc121c" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, adc081c_of_match);

@@ -149,5 +183,5 @@ static struct i2c_driver adc081c_driver = {
 module_i2c_driver(adc081c_driver);
 
 MODULE_AUTHOR("Thierry Reding <[email protected]>");
-MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
+MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
 MODULE_LICENSE("GPL v2");

Using this requires software triggers like CONFIG_IIO_HRTIMER_TRIGGER.

The device can be configured to do internal periodic sampling but does not offer some sort of interrupt on data ready. Interrupts can only trigger when values get out of a specific range.

Signed-off-by Crestez Dan Leonard <[email protected]>

---
 drivers/iio/adc/ti-adc081c.c | 63 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 54 insertions(+), 9 deletions(-)

drivers/iio/adc/ti-adc081c.c +23 -5

index 3b3c656..d024df2 100644
@@ -24,6 +24,9 @@
 #include <linux/of.h>
 
 #include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 #include <linux/regulator/consumer.h>
 
 struct adc081c {

@@ -69,18 +72,31 @@ static int adc081c_read_raw(struct iio_dev *iio,
 	return -EINVAL;
 }
 
-static const struct iio_chan_spec adc081c_channel = {
-	.type = IIO_VOLTAGE,
-	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
-	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-};
+#define ADCxx1C_CHAN(_bits) {					\
+	.type = IIO_VOLTAGE,					\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = (_bits),				\
+		.storagebits = 16,				\
+		.shift = 12 - (_bits),				\
+		.endianness = IIO_CPU,				\
+	},							\
+}
 
 struct adcxx1c_model {
+	const struct iio_chan_spec* channels;
 	int bits;
 };
 
 #define DEFINE_ADCxx1C_MODEL(_name, _bits)				\
+	static const struct iio_chan_spec _name ## _channels[] = {	\
+		ADCxx1C_CHAN((_bits)),					\
+		IIO_CHAN_SOFT_TIMESTAMP(1),				\
+	};								\
 	static const struct adcxx1c_model _name ## _model = {		\
+		.channels = _name ## _channels,				\
 		.bits = (_bits),					\
 	}
 

@@ -88,11 +104,31 @@ DEFINE_ADCxx1C_MODEL(adc081c,  8);
 DEFINE_ADCxx1C_MODEL(adc101c, 10);
 DEFINE_ADCxx1C_MODEL(adc121c, 12);
 
+#define ADC081C_NUM_CHANNELS 2
+
 static const struct iio_info adc081c_info = {

drivers/iio/adc/ti-adc081c.c +12 -0

+	int ret;
+
+	ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
+	if (ret < 0)
+		goto out;
+	buf[0] = ret;
+	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
+out:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
 static int adc081c_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {

drivers/iio/adc/ti-adc081c.c +11 -2

+
+	err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
+	if (err < 0) {
+		dev_err(&client->dev, "iio triggered buffer setup failed\n");
+		goto err_regulator_disable;
+	}
 
 	err = iio_device_register(iio);
 	if (err < 0)
-		goto regulator_disable;
+		goto err_buffer_cleanup;
 
 	i2c_set_clientdata(client, iio);
 
 	return 0;
 
-regulator_disable:
+err_buffer_cleanup:
+	iio_triggered_buffer_cleanup(iio);
+err_regulator_disable:
 	regulator_disable(adc->ref);
 
 	return err;

@@ -148,6 +192,7 @@ static int adc081c_remove(struct i2c_client *client)
 	struct adc081c *adc = iio_priv(iio);
 
 	iio_device_unregister(iio);
+	iio_triggered_buffer_cleanup(iio);
 	regulator_disable(adc->ref);
 
 	return 0;