On 14/01/17 21:21, Slawomir Stepien wrote: > From: Matt Weber <matthew.weber@xxxxxxxxxxxxxxxxxxx> > > Add implementation for Maxim Integrated 5481, 5482, 5483, > and 5484 digital potentiometer devices. > > 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> > Signed-off-by: Slawomir Stepien <sst@xxxxxxxxx> A few more bits an pieces. Thanks, Jonathan > --- > > This is my resubmission of this patch after original authors decided not to > pursuit it inclusion into kernel. > > Tested using signal analyzer. > > Changes since v2: > * spi write buffer moved to struct max5481_data and ____cacheline_aligned. > * max5481_write_cmd now uses pointer to struct max5481_data as a first argument. > > Changes since v1: > * removed not needed '``' and 'c' chars > * includes are now sorted > * added coma to last item in enum max5481_variant > * removed maxpos from struct max5481_cfg > * max5481_CHANNEL is no MAX5481_CHANNEL and it does not have 'ch' argument > * max5481_write_cmd is now based around switch > * removed not needed cast in max5481_write_cmd > * wpier state is saved after iio_device_unregister > * changed names in spi_device_id and acpi_device_id to be equal to names in of_device_id > > --- > .../bindings/iio/potentiometer/max5481.txt | 23 +++ > drivers/iio/potentiometer/Kconfig | 11 ++ > drivers/iio/potentiometer/Makefile | 1 + > drivers/iio/potentiometer/max5481.c | 216 +++++++++++++++++++++ > 4 files changed, 251 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 000000000000..6a91b106e076 > --- /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>; > + reg = <0>; /* chip-select */ > +}; > diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig > index 2e9da1cf3297..8bf282510be6 100644 > --- a/drivers/iio/potentiometer/Kconfig > +++ b/drivers/iio/potentiometer/Kconfig > @@ -15,6 +15,17 @@ 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. > + > 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 8adb58f38c0b..2260d40e0936 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 000000000000..559f1635be0a > --- /dev/null > +++ b/drivers/iio/potentiometer/max5481.c > @@ -0,0 +1,216 @@ > +/* > + * 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/acpi.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/spi/spi.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, > +}; > + > +struct max5481_cfg { > + int kohms; > +}; > + > +static const struct max5481_cfg max5481_cfg[] = { > + [max5481] = { .kohms = 10, }, > + [max5482] = { .kohms = 50, }, > + [max5483] = { .kohms = 10, }, > + [max5484] = { .kohms = 50, }, > +}; > + > +struct max5481_data { > + struct spi_device *spi; > + const struct max5481_cfg *cfg; > + u8 msg[3] ____cacheline_aligned; > +}; > + > +#define MAX5481_CHANNEL { \ > + .type = IIO_RESISTANCE, \ > + .indexed = 1, \ > + .output = 1, \ > + .channel = 0, \ > + .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, > +}; > + > +static int max5481_write_cmd(struct max5481_data *data, u8 cmd, u16 val) > +{ > + struct spi_device *spi = data->spi; > + > + data->msg[0] = cmd; > + > + switch (cmd) { > + case MAX5481_WRITE_WIPER: > + data->msg[1] = val >> 2; > + data->msg[2] = (val & 0x3) << 6; > + return spi_write(spi, data->msg, ARRAY_SIZE(data->msg)); array_size will give you the number of elements in the array. Here that is fine, but inconsistent with the use of sizeof(data->msg[0]) below. > + > + case MAX5481_COPY_AB_TO_NV: > + case MAX5481_COPY_NV_TO_AB: > + return spi_write(spi, data->msg, sizeof(data->msg[0])); > + > + default: > + return -EIO; > + } > +} > + > +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 = MAX5481_MAX_POS; > + > + 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 > MAX5481_MAX_POS) > + return -EINVAL; > + > + return max5481_write_cmd(data, 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; To use the of data you have below this will need different handling, specifically the use of of_match_device to get access to the data. See something like adc/max1363 for how to do this. > + 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, 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); > + struct max5481_data *data = iio_priv(indio_dev); > + > + iio_device_unregister(indio_dev); > + > + /* save wiper reg to NV reg */ > + return max5481_write_cmd(data, MAX5481_COPY_AB_TO_NV, 0); > +} > + > +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"); > 1 -- 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
