On Wed, 10 Jan 2018 14:17:31 +0800 Phil Reid <preid@xxxxxxxxxxxxxxxxx> wrote: > Add implementation for Analog Devices AD5272 and AD5274 digital > potentiometer devices. > > Signed-off-by: Phil Reid <preid@xxxxxxxxxxxxxxxxx> Hi Phil, A few minor comments inline, but looking pretty good. Jonathan > --- > drivers/iio/potentiometer/Kconfig | 10 ++ > drivers/iio/potentiometer/Makefile | 1 + > drivers/iio/potentiometer/ad5272.c | 219 +++++++++++++++++++++++++++++++++++++ > 3 files changed, 230 insertions(+) > create mode 100644 drivers/iio/potentiometer/ad5272.c > > diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig > index 8bf2825..0b04063 100644 > --- a/drivers/iio/potentiometer/Kconfig > +++ b/drivers/iio/potentiometer/Kconfig > @@ -5,6 +5,16 @@ > > menu "Digital potentiometers" > > +config AD5272 > + tristate "Analog Devices AD5272 Digital Potentiometer driver" > + depends on I2C > + help > + Say yes here to build support for the Analog Devices AD5272 > + digital potentiometer chip. > + > + To compile this driver as a module, choose M here: the > + module will be called ad5272. > + > config DS1803 > tristate "Maxim Integrated DS1803 Digital Potentiometer driver" > depends on I2C > diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile > index 2260d40..498bbb8 100644 > --- a/drivers/iio/potentiometer/Makefile > +++ b/drivers/iio/potentiometer/Makefile > @@ -3,6 +3,7 @@ > # > > # When adding new entries keep the list in alphabetical order > +obj-$(CONFIG_AD5272) += ad5272.o > obj-$(CONFIG_DS1803) += ds1803.o > obj-$(CONFIG_MAX5481) += max5481.o > obj-$(CONFIG_MAX5487) += max5487.o > diff --git a/drivers/iio/potentiometer/ad5272.c b/drivers/iio/potentiometer/ad5272.c > new file mode 100644 > index 0000000..b9208c2 > --- /dev/null > +++ b/drivers/iio/potentiometer/ad5272.c > @@ -0,0 +1,219 @@ > +/* > + * Analog Devices AD5372 digital potentiometer driver > + * Copyright (C) 2018 Phil Reid <preid@xxxxxxxxxxxxxxxxx> > + * > + * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf > + * > + * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address > + * ad5272 1 1024 20, 50, 100 01011xx > + * ad5274 1 256 20, 100 01011xx > + * > + * 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. Could go all SPDX with the gpl part of this. Personally I don't mind much but we'll probably end up converting it over soon anyway. > + */ > + > +#include <linux/gpio/consumer.h> > +#include <linux/i2c.h> > +#include <linux/iio/iio.h> > +#include <linux/module.h> > + > +#define AD5272_RDAC_WR 1 > +#define AD5272_RDAC_RD 2 > +#define AD5272_CTL 7 > + > +#define AD5272_RDAC_WR_EN BIT(1) > + > +struct ad5272_cfg { > + int max_pos; > + int kohms; > + int shift; > +}; > + > +enum ad5272_type { > + AD5272_020, > + AD5272_050, > + AD5272_100, > + AD5274_020, > + AD5274_100, > +}; > + > +static const struct ad5272_cfg ad5272_cfg[] = { > + /* on-semiconductor parts */ > + [AD5272_020] = { .max_pos = 1024, .kohms = 20 }, > + [AD5272_050] = { .max_pos = 1024, .kohms = 50 }, > + [AD5272_100] = { .max_pos = 1024, .kohms = 100 }, > + [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 }, > + [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 }, > +}; > + > +struct ad5272_data { > + struct i2c_client *client; > + struct mutex lock; > + const struct ad5272_cfg *cfg; > +}; > + > +static const struct iio_chan_spec ad5272_channel = { > + .type = IIO_RESISTANCE, > + .output = 1, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), > + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), > +}; > + > +static int ad5272_write(struct ad5272_data *data, int reg, int val) > +{ > + u8 buf[2]; > + int ret; > + > + buf[0] = ((reg & 0xf) << 2) | ((val >> 8) & 0x3); > + buf[1] = (u8)val; again, could do as buf[2] = {...}; > + > + mutex_lock(&data->lock); > + ret = i2c_master_send(data->client, buf, 2); sizeof(buf) preferred. > + mutex_unlock(&data->lock); > + return ret < 0 ? ret : 0; > +} > + > +static int ad5272_read(struct ad5272_data *data, int reg, int *val) > +{ > + u8 buf[2]; Could assign value here for compactness. u8 buf[2] = {(reg & 0xf) << 2, 0); It's a little paranoid to mask reg given you are controlling it entirely in the driver and anything of more than 4 bits is a bug anyway. > + int ret; > + > + buf[0] = (reg & 0xf) << 2; > + buf[1] = 0; > + > + mutex_lock(&data->lock); > + ret = i2c_master_send(data->client, buf, 2); > + if (ret < 0) > + goto error; > + > + ret = i2c_master_recv(data->client, buf, 2); > + if (ret < 0) > + goto error; > + > + *val = ((buf[0] & 0x3) << 8) | buf[1]; > + ret = 0; > +error: > + mutex_unlock(&data->lock); > + return ret; > +} > + > +static int ad5272_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct ad5272_data *data = iio_priv(indio_dev); > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: { > + ret = ad5272_read(data, AD5272_RDAC_RD, val); > + *val = *val >> data->cfg->shift; > + return ret ? ret : IIO_VAL_INT; > + } > + case IIO_CHAN_INFO_SCALE: > + *val = 1000 * data->cfg->kohms; > + *val2 = data->cfg->max_pos; > + return IIO_VAL_FRACTIONAL; > + } > + > + return -EINVAL; > +} > + > +static int ad5272_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct ad5272_data *data = iio_priv(indio_dev); > + > + if (mask != IIO_CHAN_INFO_RAW) > + return -EINVAL; > + > + if (val >= data->cfg->max_pos || val < 0) > + return -EINVAL; Also verify that val2 = 0 as otherwise the classic 1.999999 evaluates to 1 rather surprises users. > + > + val = val << data->cfg->shift; I would role this into the next line. return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift); > + > + return ad5272_write(data, AD5272_RDAC_WR, val); > +} > + > +static const struct iio_info ad5272_info = { > + .read_raw = ad5272_read_raw, > + .write_raw = ad5272_write_raw, > + .driver_module = THIS_MODULE, .driver_module no longer exists so just drop this. We do the equivalent with some macro tricks to avoid having to have this same line in every driver. > +}; > + > +static int ad5272_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct device *dev = &client->dev; > + struct gpio_desc *reset_gpio; > + struct iio_dev *indio_dev; > + struct ad5272_data *data; > + int ret; > + > + reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", > + GPIOD_OUT_LOW); > + if (IS_ERR(reset_gpio)) > + return PTR_ERR(reset_gpio); > + > + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); > + if (!indio_dev) > + return -ENOMEM; > + > + i2c_set_clientdata(client, indio_dev); > + > + data = iio_priv(indio_dev); > + data->client = client; > + mutex_init(&data->lock); > + data->cfg = &ad5272_cfg[id->driver_data]; Calling it cfg kind of implies config to me whereas this is chip type specific data. > + > + ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN); > + if (ret < 0) > + return -ENODEV; > + > + indio_dev->dev.parent = dev; > + indio_dev->info = &ad5272_info; > + indio_dev->channels = &ad5272_channel; > + indio_dev->num_channels = 1; > + indio_dev->name = client->name; > + > + return devm_iio_device_register(dev, indio_dev); > +} > + > +#if defined(CONFIG_OF) > +static const struct of_device_id ad5272_dt_ids[] = { > + { .compatible = "adi,ad5272-020", .data = &ad5272_cfg[AD5272_020] }, Why do this rather than stash the index in the data parameter and look up later (more consistent with the i2c_device_id table below)? > + { .compatible = "adi,ad5272-050", .data = &ad5272_cfg[AD5272_050] }, > + { .compatible = "adi,ad5272-100", .data = &ad5272_cfg[AD5272_100] }, > + { .compatible = "adi,ad5274-020", .data = &ad5272_cfg[AD5274_020] }, > + { .compatible = "adi,ad5274-100", .data = &ad5272_cfg[AD5274_100] }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, ad5272_dt_ids); > +#endif /* CONFIG_OF */ > + > +static const struct i2c_device_id ad5272_id[] = { > + { "ad5272-020", AD5272_020 }, > + { "ad5272-050", AD5272_050 }, > + { "ad5272-100", AD5272_100 }, > + { "ad5274-020", AD5274_020 }, > + { "ad5274-100", AD5274_100 }, > + {} > +}; > +MODULE_DEVICE_TABLE(i2c, ad5272_id); > + > +static struct i2c_driver ad5272_driver = { > + .driver = { > + .name = "ad5272", > + .of_match_table = of_match_ptr(ad5272_dt_ids), > + }, > + .probe = ad5272_probe, > + .id_table = ad5272_id, > +}; > + > +module_i2c_driver(ad5272_driver); > + > +MODULE_AUTHOR("Phil Reid <preid@xxxxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("AD5272 digital potentiometer"); > +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
