[PATCH v2 1/2] ti-adc081c: Add support for adc101c* and adc121c*

Crestez Dan Leonard
2016-04-04T18:22:05Z

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 <leonard.crestez@intel.com>
---
drivers/iio/adc/Kconfig | 6 +++---
drivers/iio/adc/ti-adc081c.c | 42 ++++++++++++++++++++++++++++++++++++++----
2 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 9ddcd5d..a2d0db5 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -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.
diff --git a/drivers/iio/adc/ti-adc081c.c b/drivers/iio/adc/ti-adc081c.c
index ecbc121..3b3c656 100644
--- a/drivers/iio/adc/ti-adc081c.c
+++ b/drivers/iio/adc/ti-adc081c.c
@@ -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;
+};
+
+#define DEFINE_ADCxx1C_MODEL(_name, _bits) \
+ static const struct adcxx1c_model _name ## _model = { \
+ .bits = (_bits), \
+ }
+
+DEFINE_ADCxx1C_MODEL(adc081c, 8);
+DEFINE_ADCxx1C_MODEL(adc101c, 10);
+DEFINE_ADCxx1C_MODEL(adc121c, 12);
+
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))
@@ -124,7 +154,9 @@ static int adc081c_remove(struct i2c_client *client)
}

static const struct i2c_device_id adc081c_id[] = {
- { "adc081c", 0 },
+ { "adc081c", (long)&adc081c_model },
+ { "adc101c", (long)&adc101c_model },
+ { "adc121c", (long)&adc121c_model },
{ }
};
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 <thierry.reding@avionic-design.de>");
-MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
+MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
MODULE_LICENSE("GPL v2");
--
2.5.5