> Add implementation for Maxim Integrated 5481, 5482, 5483, > and 5484 digital potentiometer devices. nitpicking below > Datasheet: > http://datasheets.maximintegrated.com/en/ds/MAX5481-MAX5484.pdf > > Signed-off-by: Maury Anderson <maury.anderson@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Matthew Weber <matthew.weber@xxxxxxxxxxxxxxxxxxx> > --- > > This patch is a proposed implementation which compiles and > is based on the 5487 part. The integration of the component > was cancelled but we wanted to still share this work hoping > that others might pick it up. > > --- > .../bindings/iio/potentiometer/max5481.txt | 23 +++ > drivers/iio/potentiometer/Kconfig | 12 ++ > drivers/iio/potentiometer/Makefile | 1 + > drivers/iio/potentiometer/max5481.c | 212 +++++++++++++++++++++ > 4 files changed, 248 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iio/potentiometer/max5481.txt > create mode 100644 drivers/iio/potentiometer/max5481.c > > diff --git a/Documentation/devicetree/bindings/iio/potentiometer/max5481.txt b/Documentation/devicetree/bindings/iio/potentiometer/max5481.txt > new file mode 100644 > index 0000000..3bc59b4 > --- /dev/null > +++ b/Documentation/devicetree/bindings/iio/potentiometer/max5481.txt > @@ -0,0 +1,23 @@ > +* Maxim Linear-Taper Digital Potentiometer MAX5481-MAX5484 > + > +The node for this driver must be a child node of a SPI controller, hence > +all mandatory properties described in > + > + Documentation/devicetree/bindings/spi/spi-bus.txt > + > +must be specified. > + > +Required properties: > + - compatible: Must be one of the following, depending on the > + model: > + "maxim,max5481" > + "maxim,max5482" > + "maxim,max5483" > + "maxim,max5484" > + > +Example: > +max548x: max548x@0 { > + compatible = "maxim,max5482"; > + spi-max-frequency = <7000000``>; there are two backticks ``? > + reg = <0>; /* chip-select */ > +}; > diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig > index 2e9da1c..872b25b 100644 > --- a/drivers/iio/potentiometer/Kconfig > +++ b/drivers/iio/potentiometer/Kconfig > @@ -15,6 +15,18 @@ config DS1803 > To compile this driver as a module, choose M here: the > module will be called ds1803. > > +config MAX5481 > + tristate "Maxim MAX5481-MAX5484 Digital Potentiometer driver" > + depends on SPI > + help > + Say yes here to build support for the Maxim > + MAX5481, MAX5482, MAX5483, MAX5484 digital potentiometer > + chips. > + > + To compile this driver as a module, choose M here: the > + module will be called max5481. > + > +c there is an extra 'c' > config MAX5487 > tristate "Maxim MAX5487/MAX5488/MAX5489 Digital Potentiometer driver" > depends on SPI > diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile > index 8adb58f..2260d40 100644 > --- a/drivers/iio/potentiometer/Makefile > +++ b/drivers/iio/potentiometer/Makefile > @@ -4,6 +4,7 @@ > > # When adding new entries keep the list in alphabetical order > obj-$(CONFIG_DS1803) += ds1803.o > +obj-$(CONFIG_MAX5481) += max5481.o > obj-$(CONFIG_MAX5487) += max5487.o > obj-$(CONFIG_MCP4131) += mcp4131.o > obj-$(CONFIG_MCP4531) += mcp4531.o > diff --git a/drivers/iio/potentiometer/max5481.c b/drivers/iio/potentiometer/max5481.c > new file mode 100644 > index 0000000..f3feefc > --- /dev/null > +++ b/drivers/iio/potentiometer/max5481.c > @@ -0,0 +1,212 @@ > +/* > + * Maxim Integrated MAX5481-MAX5484 digital potentiometer driver > + * Copyright 2016 Rockwell Collins > + * > + * Datasheet: > + * http://datasheets.maximintegrated.com/en/ds/MAX5481-MAX5484.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/module.h> > +#include <linux/spi/spi.h> > +#include <linux/of.h> > +#include <linux/acpi.h> > + > +#include <linux/iio/sysfs.h> > +#include <linux/iio/iio.h> > + > +/* write wiper reg */ > +#define MAX5481_WRITE_WIPER (0 << 4) > +/* copy wiper reg to NV reg */ > +#define MAX5481_COPY_AB_TO_NV (2 << 4) > +/* copy NV reg to wiper reg */ > +#define MAX5481_COPY_NV_TO_AB (3 << 4) > + > +#define MAX5481_MAX_POS 1023 > + > +enum max5481_variant { > + max5481, > + max5482, > + max5483, > + max5484 add , on the last line, chances are the list will be extended... > +}; > + > +struct max5481_cfg { > + int kohms; > + int maxpos; > +}; > + > +static const struct max5481_cfg max5481_cfg[] = { > + [max5481] = { .kohms = 10, .maxpos = MAX5481_MAX_POS }, > + [max5482] = { .kohms = 50, .maxpos = MAX5481_MAX_POS }, > + [max5483] = { .kohms = 10, .maxpos = MAX5481_MAX_POS }, > + [max5484] = { .kohms = 50, .maxpos = MAX5481_MAX_POS }, > +}; what is the difference between parts? > + > +struct max5481_data { > + struct spi_device *spi; > + const struct max5481_cfg *cfg; > +}; > + > +#define max5481_CHANNEL(ch) { \ MAX5481_CHANNEL is the ch parameter needed? > + .type = IIO_RESISTANCE, \ > + .indexed = 1, \ > + .output = 1, \ > + .channel = (ch), \ > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ > +} > + > +static const struct iio_chan_spec max5481_channels[] = { > + max5481_CHANNEL(0), > +}; > + > +static int max5481_write_cmd(struct spi_device *spi, int cmd, int val) > +{ > + /* SPI Format from MAX5481-MAX5484 (19-3708; Rev 5; 4/10) pg 15 */ > + u8 msg[3] = { > + (u8)cmd, cast (u8) needed? > + (u8)((u16)val >> 2), > + (u8)(val & 0x3) << 6 > + }; > + > + return spi_write(spi, msg, (cmd == MAX5481_WRITE_WIPER) ? sizeof(msg) : sizeof(u8)); > +} > + > +static int max5481_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct max5481_data *data = iio_priv(indio_dev); > + > + if (mask != IIO_CHAN_INFO_SCALE) > + return -EINVAL; > + > + *val = 1000 * data->cfg->kohms; > + *val2 = data->cfg->maxpos; > + > + return IIO_VAL_FRACTIONAL; > +} > + > +static int max5481_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct max5481_data *data = iio_priv(indio_dev); > + > + if (mask != IIO_CHAN_INFO_RAW) > + return -EINVAL; > + > + if (val < 0 || val > data->cfg->maxpos) > + return -EINVAL; > + > + return max5481_write_cmd(data->spi, MAX5481_WRITE_WIPER, val); > +} > + > +static const struct iio_info max5481_info = { > + .read_raw = max5481_read_raw, > + .write_raw = max5481_write_raw, > + .driver_module = THIS_MODULE, > +}; > + > +static int max5481_probe(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev; > + struct max5481_data *data; > + const struct spi_device_id *id = spi_get_device_id(spi); > + int ret; > + > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data)); > + if (!indio_dev) > + return -ENOMEM; > + > + dev_set_drvdata(&spi->dev, indio_dev); > + data = iio_priv(indio_dev); > + > + data->spi = spi; > + data->cfg = &max5481_cfg[id->driver_data]; > + > + indio_dev->name = id->name; > + indio_dev->dev.parent = &spi->dev; > + indio_dev->modes = INDIO_DIRECT_MODE; > + > + /* variant specific configuration */ > + indio_dev->info = &max5481_info; > + indio_dev->channels = max5481_channels; > + indio_dev->num_channels = ARRAY_SIZE(max5481_channels); > + > + /* restore wiper from NV */ > + ret = max5481_write_cmd(data->spi, MAX5481_COPY_NV_TO_AB, 0); > + if (ret < 0) > + return ret; > + > + return iio_device_register(indio_dev); > +} > + > +static int max5481_remove(struct spi_device *spi) > +{ > + struct iio_dev *indio_dev = dev_get_drvdata(&spi->dev); > + int ret; > + > + /* save wiper reg to NV reg */ > + ret = max5481_write_cmd(spi, MAX5481_COPY_AB_TO_NV, 0); > + > + iio_device_unregister(indio_dev); unregister first, then save > + > + return ret; > +} > + > +static const struct spi_device_id max5481_id_table[] = { > + { "MAX5481", max5481 }, > + { "MAX5482", max5482 }, > + { "MAX5483", max5483 }, > + { "MAX5484", max5484 }, > + { } > +}; > +MODULE_DEVICE_TABLE(spi, max5481_id_table); > + > +#if defined(CONFIG_OF) > +static const struct of_device_id max5481_match[] = { > + { .compatible = "maxim,max5481", .data = &max5481_cfg[max5481] }, > + { .compatible = "maxim,max5482", .data = &max5481_cfg[max5482] }, > + { .compatible = "maxim,max5483", .data = &max5481_cfg[max5483] }, > + { .compatible = "maxim,max5484", .data = &max5481_cfg[max5484] }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, max5481_match); > +#endif > + > +#if defined(CONFIG_ACPI) > +static const struct acpi_device_id max5481_acpi_match[] = { > + { "MAX5481", max5481 }, > + { "MAX5482", max5482 }, > + { "MAX5483", max5483 }, > + { "MAX5484", max5484 }, > + { } > +}; > +MODULE_DEVICE_TABLE(acpi, max5481_acpi_match); > +#endif > + > +static struct spi_driver max5481_driver = > +{ > + .driver = > + { > + .name = "max5481", > + .owner = THIS_MODULE, > + .of_match_table = of_match_ptr(max5481_match), > + .acpi_match_table = ACPI_PTR(max5481_acpi_match), > + }, > + .probe = max5481_probe, > + .remove = max5481_remove, > + .id_table = max5481_id_table, > +}; > + > +module_spi_driver(max5481_driver); > + > +MODULE_AUTHOR("Maury Anderson <maury.anderson@xxxxxxxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("max5481 SPI driver"); > +MODULE_LICENSE("GPL v2"); > -- Peter Meerwald-Stadler +43-664-2444418 (mobile) -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
