[PATCH] iio: adc: add driver for ti adc081s/adc101s/adc121s

[Milan Stevanovic <milan.o.stevanovic@gmail.com>]

Signed-off-by: Milan Stevanovic <milan.o.stevanovic@gmail.com>
---
 drivers/iio/adc/Kconfig      |  10 ++
 drivers/iio/adc/Makefile     |   1 +
 drivers/iio/adc/ti-adc081s.c | 239 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 250 insertions(+)
 create mode 100644 drivers/iio/adc/ti-adc081s.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index ef86296..208238f 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -701,6 +701,16 @@ config TI_ADC081C
 	  This driver can also be built as a module. If so, the module will be
 	  called ti-adc081c.
 
+config TI_ADC081S
+	tristate "Texas Instruments ADC081S/ADC101S/ADC121S family"
+	depends on SPI
+	help
+	  If you say yes here you get support for Texas Instruments ADC081S,
+	  ADC chips.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called ti-adc081s.
+
 config TI_ADC0832
 	tristate "Texas Instruments ADC0831/ADC0832/ADC0834/ADC0838"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9572c10..020fecf 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_SUN4I_GPADC) += sun4i-gpadc-iio.o
 obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
 obj-$(CONFIG_STM32_ADC) += stm32-adc.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
+obj-$(CONFIG_TI_ADC081S) += ti-adc081s.o
 obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
 obj-$(CONFIG_TI_ADC084S021) += ti-adc084s021.o
 obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
diff --git a/drivers/iio/adc/ti-adc081s.c b/drivers/iio/adc/ti-adc081s.c
new file mode 100644
index 0000000..be9cdb7
--- /dev/null
+++ b/drivers/iio/adc/ti-adc081s.c
@@ -0,0 +1,239 @@
+/*
+ * TI ADC081S/ADC101S/ADC121S 8/10/12-bit ADC driver
+ *
+ *
+ * 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/adc081s021.pdf
+ *	http://www.ti.com/lit/ds/symlink/adc101s021.pdf
+ *	http://www.ti.com/lit/ds/symlink/adc121s021.pdf
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/acpi.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/regulator/consumer.h>
+
+struct adc081s {
+	struct spi_device *spi;
+	struct regulator *reg;
+	struct mutex lock;
+
+	/* 8, 10 or 12 */
+	int bits;
+};
+
+static int adc081s_read_raw(struct iio_dev *iio,
+			    struct iio_chan_spec const *channel, int *value,
+			    int *shift, long mask)
+{
+	struct adc081s *adc = iio_priv(iio);
+	int ret;
+	__be16 buf;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&adc->lock);
+		ret = spi_read(adc->spi, (void *) &buf, 2);
+		mutex_unlock(&adc->lock);
+		if (ret)
+			return ret;
+		*value = (be16_to_cpu(buf) & 0x0FFF) >> (12 - adc->bits);
+		*value = sign_extend32(*value, channel->scan_type.realbits - 1);
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		*value = regulator_get_voltage(adc->reg);
+		if (*value < 0)
+			return *value;
+
+		/* convert regulator output voltage to mV */
+		*value /= 1000;
+		*shift = adc->bits;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
+
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+
+#define ADCxx1S_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,				\
+	},							\
+}
+
+#define DEFINE_ADCxx1S_CHANNELS(_name, _bits)				\
+	static const struct iio_chan_spec _name ## _channels[] = {	\
+		ADCxx1S_CHAN((_bits)),					\
+		IIO_CHAN_SOFT_TIMESTAMP(1),				\
+	};								\
+
+#define ADC081S_NUM_CHANNELS 2
+
+struct adcxx1s_model {
+	const struct iio_chan_spec *channels;
+	int bits;
+};
+
+#define ADCxx1S_MODEL(_name, _bits)					\
+	{								\
+		.channels = _name ## _channels,				\
+		.bits = (_bits),					\
+	}
+
+DEFINE_ADCxx1S_CHANNELS(adc081s,  8);
+DEFINE_ADCxx1S_CHANNELS(adc101s, 10);
+DEFINE_ADCxx1S_CHANNELS(adc121s, 12);
+
+/* Model ids are indexes in _models array */
+enum adcxx1s_model_id {
+	ADC081S = 0,
+	ADC101S = 1,
+	ADC121S = 2,
+};
+
+static struct adcxx1s_model adcxx1s_models[] = {
+	ADCxx1S_MODEL(adc081s,  8),
+	ADCxx1S_MODEL(adc101s, 10),
+	ADCxx1S_MODEL(adc121s, 12),
+};
+
+static const struct iio_info adc081s_info = {
+	.read_raw = adc081s_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static int adc081s_probe(struct spi_device *spi)
+{
+	struct iio_dev *iio;
+	struct adc081s *adc;
+	struct adcxx1s_model *model;
+	int err;
+
+	if (ACPI_COMPANION(&spi->dev)) {
+		const struct acpi_device_id *ad_id;
+
+		ad_id = acpi_match_device(spi->dev.driver->acpi_match_table,
+					  &spi->dev);
+		if (!ad_id)
+			return -ENODEV;
+		model = &adcxx1s_models[ad_id->driver_data];
+	} else {
+		model = &adcxx1s_models[spi_get_device_id(spi)->driver_data];
+	}
+
+	iio = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
+	if (!iio)
+		return -ENOMEM;
+
+	adc = iio_priv(iio);
+	adc->spi = spi;
+	adc->bits = model->bits;
+	mutex_init(&adc->lock);
+
+	adc->reg = devm_regulator_get(&spi->dev, "vref");
+	if (IS_ERR(adc->reg))
+		return PTR_ERR(adc->reg);
+
+	err = regulator_enable(adc->reg);
+	if (err < 0)
+		return err;
+
+	iio->dev.parent = &spi->dev;
+	iio->dev.of_node = spi->dev.of_node;
+	iio->name = dev_name(&spi->dev);
+	iio->modes = INDIO_DIRECT_MODE;
+	iio->info = &adc081s_info;
+
+	iio->channels = model->channels;
+	iio->num_channels = ADC081S_NUM_CHANNELS;
+
+	err = iio_device_register(iio);
+	if (err < 0)
+		goto err_regulator_disable;
+
+	spi_set_drvdata(spi, iio);
+
+	return 0;
+
+err_regulator_disable:
+	regulator_disable(adc->reg);
+
+	return err;
+}
+
+static int adc081s_remove(struct spi_device *spi)
+{
+	struct iio_dev *iio = spi_get_drvdata(spi);
+	struct adc081s *adc = iio_priv(iio);
+
+	iio_device_unregister(iio);
+	regulator_disable(adc->reg);
+
+	return 0;
+}
+
+static const struct spi_device_id adc081s_id[] = {
+	{ "adc081s", ADC081S },
+	{ "adc101s", ADC101S },
+	{ "adc121s", ADC121S },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, adc081s_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id adc081s_of_match[] = {
+	{ .compatible = "ti,adc081s" },
+	{ .compatible = "ti,adc101s" },
+	{ .compatible = "ti,adc121s" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adc081s_of_match);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id adc081s_acpi_match[] = {
+	{ "ADC081S", ADC081S },
+	{ "ADC101S", ADC101S },
+	{ "ADC121S", ADC121S },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, adc081s_acpi_match);
+#endif
+
+static struct spi_driver adc081s_driver = {
+	.driver = {
+		.name = "adc081s",
+		.of_match_table = of_match_ptr(adc081s_of_match),
+		.acpi_match_table = ACPI_PTR(adc081s_acpi_match),
+	},
+	.probe = adc081s_probe,
+	.remove = adc081s_remove,
+	.id_table = adc081s_id,
+};
+module_spi_driver(adc081s_driver);
+
+MODULE_AUTHOR("Milan Stevanovic <milan.o.stevanovic@gmail.com>");
+MODULE_DESCRIPTION("Texas Instruments ADC081S/ADC101S/ADC121S driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4