Messages in this thread | | | Date | Sat, 21 Jun 2014 11:53:05 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH v5] iio: dac: mcp4902/mcp4912/mcp4922 dac driver |
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On 15/06/14 22:17, Michael Welling wrote: > This patch provides an iio device driver for the Microchip > MCP49x2 series DACs. > Normally this lot goes below the --- inorder that it doesn't then lead to really long commit messages in git. Anyhow, I just dropped this stuff during the commit. It's enough to have it in the list archives. > v5: > - Removes wildcard naming in filename and variables. > - Switches to using iio_device_register/unregister to avoid race condition. > - Removes --- around help in the Kconfig entry. > - Removes unused variable. > - Adds checking for val2 in write_raw function. > > v4: > - Removes use of old IIO_ST macro. > - Moves mosi variable to the state struct. > - Removes default vref of 2.5v. > > v3: > - Removes MCP49X2_RES_MASK and uses GENMASK directly. > - Switch from using address to channel in functions. > > v2: > - Switched to using GENMASK instead of creating a mask directly. > - Switched from using address to channel. > - Removed unnecessary feilds from channel macro. > - Made SPI buffer cachline aligned. > - Removed some uncessary bounds checking. > - Report -EINVAL when writing a value beyond the range to DAC. > - Switched to devm_iio_device_alloc. > - Created a constant for the number of channels. > - Switched to devm_ioo_device_register. > > Signed-off-by: Michael Welling <mwelling@ieee.org> Applied to the togreg branch of iio.git. Note this is initially pushed out as testing to allow the autobuilders to do there work before I commit to not rebasing the tree!
Thanks for your hard work on this. It's a nice little driver!
Jonathan > --- > drivers/iio/dac/Kconfig | 10 +++ > drivers/iio/dac/Makefile | 1 + > drivers/iio/dac/mcp4922.c | 216 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 227 insertions(+) > create mode 100644 drivers/iio/dac/mcp4922.c > > diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig > index f378ca8..f278eff 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 MCP4922 > + tristate "MCP4902, MCP4912, MCP4922 DAC driver" > + depends on SPI > + help > + Say yes here to build the driver for the Microchip MCP4902 > + MCP4912, and MCP4922 DAC devices. > + > + To compile this driver as a module, choose M here: the module > + will be called mcp4922. > + > endmenu > diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile > index bb84ad6..1010764 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_MCP4922) += mcp4922.o > diff --git a/drivers/iio/dac/mcp4922.c b/drivers/iio/dac/mcp4922.c > new file mode 100644 > index 0000000..92cf4ca > --- /dev/null > +++ b/drivers/iio/dac/mcp4922.c > @@ -0,0 +1,216 @@ > +/* > + * mcp4922.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 MCP4922_NUM_CHANNELS 2 > + > +enum mcp4922_supported_device_ids { > + ID_MCP4902, > + ID_MCP4912, > + ID_MCP4922, > +}; > + > +struct mcp4922_state { > + struct spi_device *spi; > + unsigned int value[MCP4922_NUM_CHANNELS]; > + unsigned int vref_mv; > + struct regulator *vref_reg; > + u8 mosi[2] ____cacheline_aligned; > +}; > + > +#define MCP4922_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 = { \ > + .sign = 'u', \ > + .realbits = (bits), \ > + .storagebits = 16, \ > + .shift = 12 - (bits), \ > + }, \ > +} > + > +static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val) > +{ > + state->mosi[1] = val & 0xff; > + state->mosi[0] = (addr == 0) ? 0x00 : 0x80; > + state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f); > + > + return spi_write(state->spi, state->mosi, 2); > +} > + > +static int mcp4922_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, > + int *val2, > + long mask) > +{ > + struct mcp4922_state *state = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + *val = state->value[chan->channel]; > + 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 mcp4922_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, > + int val2, > + long mask) > +{ > + struct mcp4922_state *state = iio_priv(indio_dev); > + > + if (val2 != 0) > + return -EINVAL; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + if (val > GENMASK(chan->scan_type.realbits-1, 0)) > + return -EINVAL; > + val <<= chan->scan_type.shift; > + state->value[chan->channel] = val; > + return mcp4922_spi_write(state, chan->channel, val); > + default: > + return -EINVAL; > + } > +} > + > +static const struct iio_chan_spec mcp4922_channels[3][MCP4922_NUM_CHANNELS] = { > + [ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) }, > + [ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) }, > + [ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) }, > +}; > + > +static const struct iio_info mcp4922_info = { > + .read_raw = &mcp4922_read_raw, > + .write_raw = &mcp4922_write_raw, > + .driver_module = THIS_MODULE, > +}; > + > +static int mcp4922_probe(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev; > + struct mcp4922_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)) { > + dev_err(&spi->dev, "Vref regulator not specified\n"); > + return PTR_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; > + > + spi_set_drvdata(spi, indio_dev); > + id = spi_get_device_id(spi); > + indio_dev->dev.parent = &spi->dev; > + indio_dev->info = &mcp4922_info; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = mcp4922_channels[id->driver_data]; > + indio_dev->num_channels = MCP4922_NUM_CHANNELS; > + indio_dev->name = id->name; > + > + ret = iio_device_register(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: > + regulator_disable(state->vref_reg); > + > + return ret; > +} > + > +static int mcp4922_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + struct mcp4922_state *state; > + > + iio_device_unregister(indio_dev); > + state = iio_priv(indio_dev); > + regulator_disable(state->vref_reg); > + > + return 0; > +} > + > +static const struct spi_device_id mcp4922_id[] = { > + {"mcp4902", ID_MCP4902}, > + {"mcp4912", ID_MCP4912}, > + {"mcp4922", ID_MCP4922}, > + {} > +}; > +MODULE_DEVICE_TABLE(spi, mcp4922_id); > + > +static struct spi_driver mcp4922_driver = { > + .driver = { > + .name = "mcp4922", > + .owner = THIS_MODULE, > + }, > + .probe = mcp4922_probe, > + .remove = mcp4922_remove, > + .id_table = mcp4922_id, > +}; > +module_spi_driver(mcp4922_driver); > + > +MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>"); > +MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC"); > +MODULE_LICENSE("GPL v2"); >
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