On Tue, 5 Sep 2017 11:27:00 +0200 Lukas Wunner <lukas@xxxxxxxxx> wrote: > The DACrrcS085 (rr = 08/10/12, c = 2/4) family of SPI DACs was > inherited by TI when they acquired National Semiconductor in 2011. > This driver was developed for and tested with the DAC082S085 built into > the Revolution Pi by KUNBUS, but should work with any of the other > chips as they share the same programming interface. > > There is also a family of I2C DACs with just a single channel called > DACrr1C08x (rr = 08/10/12, x = 1/5). Their programming interface is > very similar and it should be possible to extend the driver for these > chips with moderate effort. Alternatively they could be integrated into > ad5446.c. (The AD5301/AD5311/AD5321 use different power-down modes but > otherwise appear to be comparable.) > > Furthermore there is a family of 8-channel DACs called DACrr8S085 > (rr = 08/10/12) as well as two 16-bit DACs called DAC161Sxxx > (xxx = 055/997). These are more complicated devices with support for > daisy-chaining and the ability to power down each channel separately. > They could either be handled by a separate driver or integrated into the > present driver with a larger effort. > > Cc: Mathias Duckeck <m.duckeck@xxxxxxxxx> > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> Very nice. A few really minor comments inline. Thanks, Jonathan > --- > Documentation/ABI/testing/sysfs-bus-iio | 1 + > drivers/iio/dac/Kconfig | 10 + > drivers/iio/dac/Makefile | 1 + > drivers/iio/dac/ti-dac082s085.c | 347 ++++++++++++++++++++++++++++++++ > 4 files changed, 359 insertions(+) > create mode 100644 drivers/iio/dac/ti-dac082s085.c > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio > index 7eead5f97e02..407e4d1024ee 100644 > --- a/Documentation/ABI/testing/sysfs-bus-iio > +++ b/Documentation/ABI/testing/sysfs-bus-iio > @@ -522,6 +522,7 @@ Description: > Specifies the output powerdown mode. > DAC output stage is disconnected from the amplifier and > 1kohm_to_gnd: connected to ground via an 1kOhm resistor, > + 2.5kohm_to_gnd: connected to ground via a 2.5kOhm resistor, > 6kohm_to_gnd: connected to ground via a 6kOhm resistor, > 20kohm_to_gnd: connected to ground via a 20kOhm resistor, > 90kohm_to_gnd: connected to ground via a 90kOhm resistor, > diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig > index 25bed2d7d2b9..716fcb1610dd 100644 > --- a/drivers/iio/dac/Kconfig > +++ b/drivers/iio/dac/Kconfig > @@ -300,6 +300,16 @@ config STM32_DAC > config STM32_DAC_CORE > tristate > > +config TI_DAC082S085 > + tristate "Texas Instruments 8/10/12-bit 2/4-channel DAC driver" > + depends on SPI_MASTER > + help > + Driver for the Texas Instruments (formerly National Semiconductor) > + DAC082S085, DAC102S085, DAC122S085, DAC084S085, DAC104S085 and > + DAC124S085. > + > + If compiled as a module, it will be called ti-dac082s085. > + > config VF610_DAC > tristate "Vybrid vf610 DAC driver" > depends on OF > diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile > index 603587cc2f07..1a2dd507b4d8 100644 > --- a/drivers/iio/dac/Makefile > +++ b/drivers/iio/dac/Makefile > @@ -32,4 +32,5 @@ obj-$(CONFIG_MCP4725) += mcp4725.o > obj-$(CONFIG_MCP4922) += mcp4922.o > obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o > obj-$(CONFIG_STM32_DAC) += stm32-dac.o > +obj-$(CONFIG_TI_DAC082S085) += ti-dac082s085.o > obj-$(CONFIG_VF610_DAC) += vf610_dac.o > diff --git a/drivers/iio/dac/ti-dac082s085.c b/drivers/iio/dac/ti-dac082s085.c > new file mode 100644 > index 000000000000..22fdce512a09 > --- /dev/null > +++ b/drivers/iio/dac/ti-dac082s085.c > @@ -0,0 +1,347 @@ > +/* > + * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver > + * > + * Copyright (C) 2017 KUNBUS GmbH > + * > + * http://www.ti.com/lit/ds/symlink/dac082s085.pdf > + * http://www.ti.com/lit/ds/symlink/dac102s085.pdf > + * http://www.ti.com/lit/ds/symlink/dac122s085.pdf > + * http://www.ti.com/lit/ds/symlink/dac084s085.pdf > + * http://www.ti.com/lit/ds/symlink/dac104s085.pdf > + * http://www.ti.com/lit/ds/symlink/dac124s085.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/iio/iio.h> > +#include <linux/module.h> > +#include <linux/regulator/consumer.h> > +#include <linux/spi/spi.h> > + > +/** > + * struct ti_dac_chip - TI DAC chip > + * @lock: protects write sequences > + * @vref: regulator generating Vref > + * @mesg: SPI message to perform a write > + * @xfer: SPI transfer used by @mesg > + * @buf: buffer for @xfer > + * @val: cached value of each output > + * @powerdown: whether the chip is powered down > + * @powerdown_mode: selected by the user > + * @resolution: resolution of the chip > + */ > +struct ti_dac_chip { > + struct mutex lock; > + struct regulator *vref; > + struct spi_message mesg; > + struct spi_transfer xfer; > + u8 buf[2] ____cacheline_aligned; > + u16 val[4]; > + bool powerdown; > + u8 powerdown_mode; > + u8 resolution; > +}; > + > +#define WRITE_NOT_UPDATE(chan) (0x00 | (chan) << 6) > +#define WRITE_AND_UPDATE(chan) (0x10 | (chan) << 6) > +#define WRITE_ALL_UPDATE 0x20 > +#define POWERDOWN(mode) (0x30 | ((mode) + 1) << 6) > + > +static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val) > +{ > + u8 shift = 12 - ti_dac->resolution; > + > + ti_dac->buf[0] = cmd | (val >> (8 - shift)); > + ti_dac->buf[1] = (val << shift) & 0xff; > + return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg); > +} > + > +static const char * const ti_dac_powerdown_modes[] = { > + "2.5kohm_to_gnd", "100kohm_to_gnd", "three_state", > +}; > + > +static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan) > +{ > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + > + return ti_dac->powerdown_mode; > +} > + > +static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + unsigned int mode) > +{ > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + int ret; > + > + if (ti_dac->powerdown_mode == mode) > + return 0; > + > + mutex_lock(&ti_dac->lock); > + if (ti_dac->powerdown) { > + ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0); > + if (ret) { I'd slightly prefer a goto to use the unlock already found below. > + mutex_unlock(&ti_dac->lock); > + return ret; > + } > + } > + ti_dac->powerdown_mode = mode; > + mutex_unlock(&ti_dac->lock); nitpick time : blank line here > + return 0; > +} > + > +static const struct iio_enum ti_dac_powerdown_mode = { > + .items = ti_dac_powerdown_modes, > + .num_items = ARRAY_SIZE(ti_dac_powerdown_modes), > + .get = ti_dac_get_powerdown_mode, > + .set = ti_dac_set_powerdown_mode, > +}; > + > +static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev, > + uintptr_t private, > + const struct iio_chan_spec *chan, > + char *buf) > +{ > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + > + return sprintf(buf, "%d\n", ti_dac->powerdown); > +} > + > +static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev, > + uintptr_t private, > + const struct iio_chan_spec *chan, > + const char *buf, size_t len) > +{ > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + bool powerdown; > + int ret; > + > + ret = strtobool(buf, &powerdown); > + if (ret) > + return ret; > + > + if (ti_dac->powerdown == powerdown) > + return len; > + > + mutex_lock(&ti_dac->lock); > + if (powerdown) > + ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0); > + else > + ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]); > + if (!ret) > + ti_dac->powerdown = powerdown; > + mutex_unlock(&ti_dac->lock); > + > + return ret ? ret : len; > +} > + > +static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = { > + { > + .name = "powerdown", > + .read = ti_dac_read_powerdown, > + .write = ti_dac_write_powerdown, > + .shared = IIO_SHARED_BY_TYPE, > + }, > + IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode), > + IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode), > + { }, > +}; > + > +#define TI_DAC_CHANNEL(chan) { \ > + .type = IIO_VOLTAGE, \ > + .channel = (chan), \ > + .address = (chan), \ > + .indexed = true, \ > + .output = true, \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ > + .ext_info = ti_dac_ext_info, \ > +} > + > +static const struct iio_chan_spec ti_dac_channels[] = { > + TI_DAC_CHANNEL(0), > + TI_DAC_CHANNEL(1), > + TI_DAC_CHANNEL(2), > + TI_DAC_CHANNEL(3), > +}; > + > +static int ti_dac_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + *val = ti_dac->val[chan->channel]; > + ret = IIO_VAL_INT; > + break; > + > + case IIO_CHAN_INFO_SCALE: > + ret = regulator_get_voltage(ti_dac->vref); > + if (ret < 0) > + return ret; > + > + *val = ret / 1000; > + *val2 = ti_dac->resolution; > + ret = IIO_VAL_FRACTIONAL_LOG2; > + break; > + > + default: > + ret = -EINVAL; > + } > + > + return ret; > +} > + > +static int ti_dac_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + if (ti_dac->val[chan->channel] == val) > + return 0; > + > + if (val >= (1 << ti_dac->resolution) || val < 0) > + return -EINVAL; > + > + if (ti_dac->powerdown) > + return -EHOSTDOWN; Hmm. That's a relatively unusual error to find in a driver. I'd have gone with -EBUSY to indicate that you can't do it now, but might be able to in future.. > + > + mutex_lock(&ti_dac->lock); > + ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val); > + if (!ret) > + ti_dac->val[chan->channel] = val; > + mutex_unlock(&ti_dac->lock); > + break; > + > + default: > + ret = -EINVAL; > + } > + > + return ret; > +} > + > +static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, long mask) > +{ > + return IIO_VAL_INT; > +} > + > +static const struct iio_info ti_dac_info = { > + .read_raw = ti_dac_read_raw, > + .write_raw = ti_dac_write_raw, > + .write_raw_get_fmt = ti_dac_write_raw_get_fmt, > +}; > + > +static int ti_dac_probe(struct spi_device *spi) > +{ > + struct device *dev = &spi->dev; > + struct ti_dac_chip *ti_dac; > + struct iio_dev *indio_dev; > + int ret; > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac)); > + if (!indio_dev) > + return -ENOMEM; > + > + indio_dev->dev.parent = dev; > + indio_dev->info = &ti_dac_info; > + indio_dev->name = spi->modalias; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->channels = ti_dac_channels; > + spi_set_drvdata(spi, indio_dev); > + > + ti_dac = iio_priv(indio_dev); > + ti_dac->xfer.tx_buf = &ti_dac->buf; > + ti_dac->xfer.len = sizeof(ti_dac->buf); > + spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1); > + ti_dac->mesg.spi = spi; > + > + ret = sscanf(spi->modalias, "dac%2hhu%1d", > + &ti_dac->resolution, &indio_dev->num_channels); > + WARN_ON(ret != 2); Whilst this seems nice and clear now, it may not work if this driver had additional parts added in future. I would prefer an explicit table with this information in it and use an enum to reference into it. This is a bit 'too clever' :) > + > + ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0); > + if (ret) { > + dev_err(dev, "failed to initialize outputs to 0\n"); > + return ret; > + } > + > + ti_dac->vref = devm_regulator_get(dev, "vref"); > + if (IS_ERR(ti_dac->vref)) > + return PTR_ERR(ti_dac->vref); > + > + ret = regulator_enable(ti_dac->vref); > + if (ret < 0) > + return ret; > + > + mutex_init(&ti_dac->lock); > + ret = iio_device_register(indio_dev); > + if (ret) { > + mutex_destroy(&ti_dac->lock); > + regulator_disable(ti_dac->vref); > + return ret; > + } > + > + return 0; Trivial: return ret; here and get rid of it in the brackets above. > +} > + > +static int ti_dac_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = spi_get_drvdata(spi); > + struct ti_dac_chip *ti_dac = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + mutex_destroy(&ti_dac->lock); > + regulator_disable(ti_dac->vref); > + > + return 0; > +} > + > +#ifdef CONFIG_OF > +static const struct of_device_id ti_dac_of_id[] = { > + { .compatible = "ti,dac082s085" }, > + { .compatible = "ti,dac102s085" }, > + { .compatible = "ti,dac122s085" }, > + { .compatible = "ti,dac084s085" }, > + { .compatible = "ti,dac104s085" }, > + { .compatible = "ti,dac124s085" }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, ti_dac_of_id); > +#endif > + > +static const struct spi_device_id ti_dac_spi_id[] = { > + { "dac082s085" }, > + { "dac102s085" }, > + { "dac122s085" }, > + { "dac084s085" }, > + { "dac104s085" }, > + { "dac124s085" }, > + { } > +}; > +MODULE_DEVICE_TABLE(spi, ti_dac_spi_id); > + > +static struct spi_driver ti_dac_driver = { > + .driver = { > + .name = "ti-dac082s085", > + .of_match_table = of_match_ptr(ti_dac_of_id), > + }, > + .probe = ti_dac_probe, > + .remove = ti_dac_remove, > + .id_table = ti_dac_spi_id, > +}; > +module_spi_driver(ti_dac_driver); > + > +MODULE_AUTHOR("Lukas Wunner <lukas@xxxxxxxxx>"); > +MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver"); > +MODULE_LICENSE("GPL v2"); -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
