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Message-Id: <1401944595-6042-1-git-send-email-mwelling@ieee.org>
Date: Thu, 5 Jun 2014 00:03:15 -0500
From: Michael Welling <mwelling@...e.org>
To: Jonathan Cameron <jic23@...nel.org>, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org, Peter Meerwald <pmeerw@...erw.net>
Cc: Michael Welling <mwelling@...e.org>
Subject: [PATCH v2] iio: dac: mcp4902/mcp4912/mcp4922 dac driver
This patch provides an iio device driver for the Microchip
MCP49x2 series DACs.
Signed-off-by: Michael Welling <mwelling@...e.org>
---
drivers/iio/dac/Kconfig | 10 +++
drivers/iio/dac/Makefile | 1 +
drivers/iio/dac/mcp49x2.c | 213 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 224 insertions(+)
create mode 100644 drivers/iio/dac/mcp49x2.c
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index f378ca8..032d678 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -163,4 +163,14 @@ config MCP4725
To compile this driver as a module, choose M here: the module
will be called mcp4725.
+config MCP49X2
+ tristate "MCP4902, MCP4912, MCP4922 DAC driver"
+ depends on SPI
+ ---help---
+ Say yes here to build the driver for the Microchip MCP49x2
+ series DAC devices.
+
+ To compile this driver as a module, choose M here: the module
+ will be called mcp49x2.
+
endmenu
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index bb84ad6..2fdfc2e 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_AD5686) += ad5686.o
obj-$(CONFIG_AD7303) += ad7303.o
obj-$(CONFIG_MAX517) += max517.o
obj-$(CONFIG_MCP4725) += mcp4725.o
+obj-$(CONFIG_MCP49X2) += mcp49x2.o
diff --git a/drivers/iio/dac/mcp49x2.c b/drivers/iio/dac/mcp49x2.c
new file mode 100644
index 0000000..f90a83a
--- /dev/null
+++ b/drivers/iio/dac/mcp49x2.c
@@ -0,0 +1,213 @@
+/*
+ * mcp49x2.c
+ *
+ * Driver for Microchip Digital to Analog Converters.
+ * Supports MCP4902, MCP4912, and MCP4922.
+ *
+ * Copyright (c) 2014 EMAC Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/regulator/consumer.h>
+#include <linux/bitops.h>
+
+#define MCP49X2_RES_MASK(x) GENMASK(x, 0)
+#define MCP49X2_NUM_CHANNELS 2
+
+enum mcp49x2_supported_device_ids {
+ ID_MCP4902,
+ ID_MCP4912,
+ ID_MCP4922,
+};
+
+struct mcp49x2_state {
+ struct spi_device *spi;
+ unsigned int value[MCP49X2_NUM_CHANNELS];
+ unsigned int power_mode[MCP49X2_NUM_CHANNELS];
+ unsigned int vref_mv;
+ struct regulator *vref_reg;
+};
+
+#define MCP49X2_CHAN(chan, bits) { \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_type = IIO_ST('u', bits, 16, 12-bits), \
+}
+
+static int mcp49x2_spi_write(struct spi_device *spi, u8 addr, u32 val)
+{
+ u8 mosi[2] ____cacheline_aligned;
+
+ mosi[1] = val & 0xff;
+ mosi[0] = (addr == 0) ? 0x00: 0x80;
+ mosi[0] |= 0x30 | ((val >> 8) & 0x0f);
+
+ return spi_write(spi, mosi, 2);
+}
+
+static int mcp49x2_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long mask)
+{
+ struct mcp49x2_state *state = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = state->value[chan->address];
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = state->vref_mv;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int mcp49x2_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val,
+ int val2,
+ long mask)
+{
+ struct mcp49x2_state *state = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val > MCP49X2_RES_MASK(chan->scan_type.realbits))
+ return -EINVAL;
+ val <<= chan->scan_type.shift;
+ state->value[chan->address] = val;
+ return mcp49x2_spi_write(state->spi, chan->address, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec mcp49x2_channels[3][MCP49X2_NUM_CHANNELS] = {
+ [ID_MCP4902] = { MCP49X2_CHAN(0, 8), MCP49X2_CHAN(1, 8) },
+ [ID_MCP4912] = { MCP49X2_CHAN(0, 10), MCP49X2_CHAN(1, 10) },
+ [ID_MCP4922] = { MCP49X2_CHAN(0, 12), MCP49X2_CHAN(1, 12) },
+};
+
+static const struct iio_info mcp49x2_info = {
+ .read_raw = &mcp49x2_read_raw,
+ .write_raw = &mcp49x2_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int mcp49x2_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct mcp49x2_state *state;
+ const struct spi_device_id *id;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+
+ state = iio_priv(indio_dev);
+ state->spi = spi;
+ state->vref_reg = devm_regulator_get(&spi->dev, "vref");
+ if (!IS_ERR(state->vref_reg)) {
+ ret = regulator_enable(state->vref_reg);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = regulator_get_voltage(state->vref_reg);
+ if (ret < 0) {
+ dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
+ ret);
+ goto error_disable_reg;
+ }
+ state->vref_mv = ret / 1000;
+ } else {
+ dev_info(&spi->dev, "Vref regulator not specified assuming 2.5V\n");
+ state->vref_mv = 2500;
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+ id = spi_get_device_id(spi);
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &mcp49x2_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = mcp49x2_channels[id->driver_data];
+ indio_dev->num_channels = MCP49X2_NUM_CHANNELS;
+ indio_dev->name = id->name;
+
+ ret = devm_iio_device_register(&spi->dev, indio_dev);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to register iio device: %d\n",
+ ret);
+ goto error_disable_reg;
+ }
+
+ return 0;
+
+error_disable_reg:
+ if (!IS_ERR(state->vref_reg))
+ regulator_disable(state->vref_reg);
+
+ return ret;
+}
+
+static int mcp49x2_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct mcp49x2_state *state;
+
+ state = iio_priv(indio_dev);
+
+ if (!IS_ERR(state->vref_reg))
+ regulator_disable(state->vref_reg);
+
+ return 0;
+}
+
+static const struct spi_device_id mcp49x2_id[] = {
+ {"mcp4902", ID_MCP4902},
+ {"mcp4912", ID_MCP4912},
+ {"mcp4922", ID_MCP4922},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, mcp49x2_id);
+
+static struct spi_driver mcp49x2_driver = {
+ .driver = {
+ .name = "mcp49x2",
+ .owner = THIS_MODULE,
+ },
+ .probe = mcp49x2_probe,
+ .remove = mcp49x2_remove,
+ .id_table = mcp49x2_id,
+};
+module_spi_driver(mcp49x2_driver);
+
+MODULE_AUTHOR("Michael Welling <mwelling@...e.org>");
+MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5
--
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