This adds ADC0832 8-bit ADC driver. This can also support
ADC0831, ADC0834, and ADC0838 chips easily. But I currently don't
have these chips except ADC0832 and untested, so MODULE_DEVICE_TABLE
for these are disabled for now.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
Cc: Hartmut Knaack <knaack.h@xxxxxx>
Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
Cc: Peter Meerwald <pmeerw@xxxxxxxxxx>
---
.../devicetree/bindings/iio/adc/ti-adc083x.txt | 15 ++
drivers/iio/adc/Kconfig | 10 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ti-adc083x.c | 296 +++++++++++++++++++++
4 files changed, 322 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/ti-adc083x.txt
create mode 100644 drivers/iio/adc/ti-adc083x.c
diff --git a/Documentation/devicetree/bindings/iio/adc/ti-adc083x.txt b/Documentation/devicetree/bindings/iio/adc/ti-adc083x.txt
new file mode 100644
index 0000000..caace65
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti-adc083x.txt
@@ -0,0 +1,15 @@
+* Texas Instruments' ADC0832 ADC chip
+
+Required properties:
+ - compatible: Should be "ti,adc0832"
+ - reg: spi chip select number for the device
+ - vref-supply: The regulator supply for ADC reference voltage
+ - spi-max-frequency: Max SPI frequency to use (< 400000)
+
+Example:
+adc@0 {
+ compatible = "ti,adc0832";
+ reg = <0>;
+ vref-supply = <&vdd_supply>;
+ spi-max-frequency = <200000>;
+};
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index e421030..387f8df 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -333,6 +333,16 @@ config TI_ADC081C
This driver can also be built as a module. If so, the module will be
called ti-adc081c.
+config TI_ADC083X
+ tristate "Texas Instruments ADC0832"
+ depends on SPI
+ help
+ If you say yes here you get support for Texas Instruments ADC0832
+ ADC chips.
+
+ This driver can also be built as a module. If so, the module will be
+ called ti-adc083x.
+
config TI_ADC128S052
tristate "Texas Instruments ADC128S052/ADC122S021"
depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9d09b44..9815021 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
+obj-$(CONFIG_TI_ADC083X) += ti-adc083x.o
obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
diff --git a/drivers/iio/adc/ti-adc083x.c b/drivers/iio/adc/ti-adc083x.c
new file mode 100644
index 0000000..894e9cc
--- /dev/null
+++ b/drivers/iio/adc/ti-adc083x.c
@@ -0,0 +1,296 @@
+/*
+ * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver
+ *
+ * Copyright (c) 2016 Akinobu Mita <akinobu.mita@xxxxxxxxx>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Datasheet: http://www.ti.com/lit/ds/symlink/adc0832-n.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+
+enum {
+ adc0831,
+ adc0832,
+ adc0834,
+ adc0838,
+};
+
+struct adc083x {
+ struct spi_device *spi;
+ struct regulator *reg;
+ struct mutex lock;
+ u8 mux_bits;
+
+ u8 tx_buf[2] ____cacheline_aligned;
+ u8 rx_buf[2];
+};
+
+#define ADC083X_VOLTAGE_CHANNEL(chan) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+ }
+
+#define ADC083X_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (chan1), \
+ .channel2 = (chan2), \
+ .differential = 1, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+ }
+
+static const struct iio_chan_spec adc0831_channels[] = {
+ ADC083X_VOLTAGE_CHANNEL_DIFF(0, 1),
+};
+
+static const struct iio_chan_spec adc0832_channels[] = {
+ ADC083X_VOLTAGE_CHANNEL(0),
+ ADC083X_VOLTAGE_CHANNEL(1),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(1, 0),
+};
+
+static const struct iio_chan_spec adc0834_channels[] = {
+ ADC083X_VOLTAGE_CHANNEL(0),
+ ADC083X_VOLTAGE_CHANNEL(1),
+ ADC083X_VOLTAGE_CHANNEL(2),
+ ADC083X_VOLTAGE_CHANNEL(3),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(1, 0),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(2, 3),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(3, 2),
+};
+
+static const struct iio_chan_spec adc0838_channels[] = {
+ ADC083X_VOLTAGE_CHANNEL(0),
+ ADC083X_VOLTAGE_CHANNEL(1),
+ ADC083X_VOLTAGE_CHANNEL(2),
+ ADC083X_VOLTAGE_CHANNEL(3),
+ ADC083X_VOLTAGE_CHANNEL(4),
+ ADC083X_VOLTAGE_CHANNEL(5),
+ ADC083X_VOLTAGE_CHANNEL(6),
+ ADC083X_VOLTAGE_CHANNEL(7),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(1, 0),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(2, 3),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(3, 2),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(4, 5),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(5, 4),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(6, 7),
+ ADC083X_VOLTAGE_CHANNEL_DIFF(7, 6),
+};
+
+static int adc0831_adc_conversion(struct adc083x *adc)
+{
+ struct spi_device *spi = adc->spi;
+ int ret;
+
+ ret = spi_read(spi, &adc->rx_buf, 2);
+ if (ret)
+ return ret;
+
+ return (adc->rx_buf[0] << 2) | (adc->rx_buf[1] >> 6);
+}
+
+static int adc083x_adc_conversion(struct adc083x *adc, int channel,
+ bool differential)
+{
+ struct spi_device *spi = adc->spi;
+ struct spi_transfer xfer = {
+ .tx_buf = adc->tx_buf,
+ .rx_buf = adc->rx_buf,
+ .len = 2,
+ };
+ int ret;
+
+ if (!adc->mux_bits)
+ return adc0831_adc_conversion(adc);
+
+ /* start bit */
+ adc->tx_buf[0] = 1 << (adc->mux_bits + 1);
+ /* single-ended or differential */
+ adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits);
+ /* odd / sign */
+ adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1);
+ /* select */
+ if (adc->mux_bits > 1)
+ adc->tx_buf[0] |= channel / 2;
+
+ /* align Data output BIT7 (MSB) to 8-bit boundary */
+ adc->tx_buf[0] <<= 1;
+
+ ret = spi_sync_transfer(spi, &xfer, 1);
+ if (ret)
+ return ret;
+
+ return adc->rx_buf[1];
+}
+
+static int adc083x_read_raw(struct iio_dev *iio,
+ struct iio_chan_spec const *channel, int *value,
+ int *shift, long mask)
+{
+ struct adc083x *adc = iio_priv(iio);
+ int ret;
+
+ mutex_lock(&adc->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = adc083x_adc_conversion(adc, channel->channel,
+ channel->differential);
+ if (ret < 0)
+ break;
+
+ *value = ret;
+ ret = IIO_VAL_INT;
+ break;
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_get_voltage(adc->reg);
+ if (ret < 0)
+ break;
+
+ /* convert regulator output voltage to mV */
+ *value = ret / 1000;
+ *shift = 8;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ mutex_unlock(&adc->lock);
+
+ return ret;
+}
+
+static const struct iio_info adc083x_info = {
+ .read_raw = adc083x_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int adc083x_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct adc083x *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;
+ mutex_init(&adc->lock);
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &adc083x_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ switch (spi_get_device_id(spi)->driver_data) {
+ case adc0831:
+ adc->mux_bits = 0;
+ indio_dev->channels = adc0831_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0831_channels);
+ break;
+ case adc0832:
+ adc->mux_bits = 1;
+ indio_dev->channels = adc0832_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0832_channels);
+ break;
+ case adc0834:
+ adc->mux_bits = 2;
+ indio_dev->channels = adc0834_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0834_channels);
+ break;
+ case adc0838:
+ adc->mux_bits = 3;
+ indio_dev->channels = adc0838_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc0838_channels);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ 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)
+ return ret;
+
+ spi_set_drvdata(spi, indio_dev);
+
+ ret = devm_iio_device_register(&spi->dev, indio_dev);
+ if (ret)
+ regulator_disable(adc->reg);
+
+ return ret;
+}
+
+static int adc083x_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct adc083x *adc = iio_priv(indio_dev);
+
+ regulator_disable(adc->reg);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+
+static const struct of_device_id adc083x_dt_ids[] = {
+ { .compatible = "ti,adc0832", },
+/* THESE CHIPS ARE NOT TESTED
+ { .compatible = "ti,adc0831", },
+ { .compatible = "ti,adc0834", },
+ { .compatible = "ti,adc0838", },
+*/
+ {}
+};
+MODULE_DEVICE_TABLE(of, adc083x_dt_ids);
+
+#endif
+
+static const struct spi_device_id adc083x_id[] = {
+ { "adc0832", adc0832 },
+/* THESE CHIPS ARE NOT TESTED
+ { "adc0831", adc0831 },
+ { "adc0834", adc0834 },
+ { "adc0838", adc0838 },
+*/
+ {}
+};
+MODULE_DEVICE_TABLE(spi, adc083x_id);
+
+static struct spi_driver adc083x_driver = {
+ .driver = {
+ .name = "adc083x",
+ .of_match_table = of_match_ptr(adc083x_dt_ids),
+ },
+ .probe = adc083x_probe,
+ .remove = adc083x_remove,
+ .id_table = adc083x_id,
+};
+module_spi_driver(adc083x_driver);
+
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@xxxxxxxxx>");
+MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver");
+MODULE_LICENSE("GPL v2");
--
2.5.0
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