Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / iio / adc / ti-adc128s052.c

diff --git a/kernel/drivers/iio/adc/ti-adc128s052.c b/kernel/drivers/iio/adc/ti-adc128s052.c
new file mode 100644 (file)
index 0000000..655cb56
--- /dev/null
+++ b/kernel/drivers/iio/adc/ti-adc128s052.c
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
+ *
+ * Driver for Texas Instruments' ADC128S052 ADC chip.
+ * Datasheet can be found here:
+ * http://www.ti.com/lit/ds/symlink/adc128s052.pdf
+ *
+ * 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.
+ */
+
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+
+struct adc128 {
+       struct spi_device *spi;
+
+       struct regulator *reg;
+       struct mutex lock;
+
+       u8 buffer[2] ____cacheline_aligned;
+};
+
+static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
+{
+       int ret;
+
+       mutex_lock(&adc->lock);
+
+       adc->buffer[0] = channel << 3;
+       adc->buffer[1] = 0;
+
+       ret = spi_write(adc->spi, &adc->buffer, 2);
+       if (ret < 0) {
+               mutex_unlock(&adc->lock);
+               return ret;
+       }
+
+       ret = spi_read(adc->spi, &adc->buffer, 2);
+
+       mutex_unlock(&adc->lock);
+
+       if (ret < 0)
+               return ret;
+
+       return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
+}
+
+static int adc128_read_raw(struct iio_dev *indio_dev,
+                          struct iio_chan_spec const *channel, int *val,
+                          int *val2, long mask)
+{
+       struct adc128 *adc = iio_priv(indio_dev);
+       int ret;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+
+               ret = adc128_adc_conversion(adc, channel->channel);
+               if (ret < 0)
+                       return ret;
+
+               *val = ret;
+               return IIO_VAL_INT;
+
+       case IIO_CHAN_INFO_SCALE:
+
+               ret = regulator_get_voltage(adc->reg);
+               if (ret < 0)
+                       return ret;
+
+               *val = ret / 1000;
+               *val2 = 12;
+               return IIO_VAL_FRACTIONAL_LOG2;
+
+       default:
+               return -EINVAL;
+       }
+
+}
+
+#define ADC128_VOLTAGE_CHANNEL(num)    \
+       { \
+               .type = IIO_VOLTAGE, \
+               .indexed = 1, \
+               .channel = (num), \
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+       }
+
+static const struct iio_chan_spec adc128_channels[] = {
+       ADC128_VOLTAGE_CHANNEL(0),
+       ADC128_VOLTAGE_CHANNEL(1),
+       ADC128_VOLTAGE_CHANNEL(2),
+       ADC128_VOLTAGE_CHANNEL(3),
+       ADC128_VOLTAGE_CHANNEL(4),
+       ADC128_VOLTAGE_CHANNEL(5),
+       ADC128_VOLTAGE_CHANNEL(6),
+       ADC128_VOLTAGE_CHANNEL(7),
+};
+
+static const struct iio_info adc128_info = {
+       .read_raw = adc128_read_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static int adc128_probe(struct spi_device *spi)
+{
+       struct iio_dev *indio_dev;
+       struct adc128 *adc;
+       int ret;
+
+       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
+       if (!indio_dev)
+               return -ENOMEM;
+
+       adc = iio_priv(indio_dev);
+       adc->spi = spi;
+
+       spi_set_drvdata(spi, indio_dev);
+
+       indio_dev->dev.parent = &spi->dev;
+       indio_dev->name = spi_get_device_id(spi)->name;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->info = &adc128_info;
+
+       indio_dev->channels = adc128_channels;
+       indio_dev->num_channels = ARRAY_SIZE(adc128_channels);
+
+       adc->reg = devm_regulator_get(&spi->dev, "vref");
+       if (IS_ERR(adc->reg))
+               return PTR_ERR(adc->reg);
+
+       ret = regulator_enable(adc->reg);
+       if (ret < 0)
+               return ret;
+
+       mutex_init(&adc->lock);
+
+       ret = iio_device_register(indio_dev);
+
+       return ret;
+}
+
+static int adc128_remove(struct spi_device *spi)
+{
+       struct iio_dev *indio_dev = spi_get_drvdata(spi);
+       struct adc128 *adc = iio_priv(indio_dev);
+
+       iio_device_unregister(indio_dev);
+       regulator_disable(adc->reg);
+
+       return 0;
+}
+
+static const struct spi_device_id adc128_id[] = {
+       { "adc128s052", 0},
+       { }
+};
+MODULE_DEVICE_TABLE(spi, adc128_id);
+
+static struct spi_driver adc128_driver = {
+       .driver = {
+               .name = "adc128s052",
+               .owner = THIS_MODULE,
+       },
+       .probe = adc128_probe,
+       .remove = adc128_remove,
+       .id_table = adc128_id,
+};
+module_spi_driver(adc128_driver);
+
+MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
+MODULE_DESCRIPTION("Texas Instruments ADC128S052");
+MODULE_LICENSE("GPL v2");