diff options
Diffstat (limited to 'drivers/iio/amplifiers/hmc425a.c')
| -rw-r--r-- | drivers/iio/amplifiers/hmc425a.c | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc425a.c new file mode 100644 index 000000000000..4dbf894c7e3b --- /dev/null +++ b/drivers/iio/amplifiers/hmc425a.c @@ -0,0 +1,425 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * HMC425A and similar Gain Amplifiers + * + * Copyright 2020, 2024 Analog Devices Inc. + */ + +#include <linux/bits.h> +#include <linux/bitops.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/kernel.h> +#include <linux/math.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/regulator/consumer.h> +#include <linux/sysfs.h> + +/* + * The LTC6373 amplifier supports configuring gain using GPIO's with the following + * values (OUTPUT_V / INPUT_V): 0(shutdown), 0.25, 0.5, 1, 2, 4, 8, 16 + * + * Except for the shutdown value, all can be converted to dB using 20 * log10(x) + * From here, it is observed that all values are multiples of the '2' gain setting, + * with the correspondent of 6.020dB. + */ +#define LTC6373_CONVERSION_CONSTANT 6020 +#define LTC6373_MIN_GAIN_CODE 0x6 +#define LTC6373_CONVERSION_MASK GENMASK(2, 0) +#define LTC6373_SHUTDOWN GENMASK(2, 0) + +enum hmc425a_type { + ID_HMC425A, + ID_HMC540S, + ID_ADRF5740, + ID_LTC6373, +}; + +struct hmc425a_chip_info { + const char *name; + const struct iio_chan_spec *channels; + unsigned int num_channels; + unsigned int num_gpios; + int gain_min; + int gain_max; + int default_gain; + int powerdown_val; + bool has_powerdown; + + int (*gain_dB_to_code)(int gain, int *code); + int (*code_to_gain_dB)(int code, int *val, int *val2); +}; + +struct hmc425a_state { + struct mutex lock; /* protect sensor state */ + const struct hmc425a_chip_info *chip_info; + struct gpio_descs *gpios; + u32 gain; + bool powerdown; +}; + +static int gain_dB_to_code(struct hmc425a_state *st, int val, int val2, int *code) +{ + const struct hmc425a_chip_info *inf = st->chip_info; + int gain; + + if (val < 0) + gain = (val * 1000) - (val2 / 1000); + else + gain = (val * 1000) + (val2 / 1000); + + if (gain > inf->gain_max || gain < inf->gain_min) + return -EINVAL; + if (st->powerdown) + return -EPERM; + + return st->chip_info->gain_dB_to_code(gain, code); +} + +static int hmc425a_gain_dB_to_code(int gain, int *code) +{ + *code = ~((abs(gain) / 500) & 0x3F); + return 0; +} + +static int hmc540s_gain_dB_to_code(int gain, int *code) +{ + *code = ~((abs(gain) / 1000) & 0xF); + return 0; +} + +static int adrf5740_gain_dB_to_code(int gain, int *code) +{ + int temp = (abs(gain) / 2000) & 0xF; + + /* Bit [0-3]: 2dB 4dB 8dB 8dB */ + *code = temp & BIT(3) ? temp | BIT(2) : temp; + return 0; +} + +static int ltc6373_gain_dB_to_code(int gain, int *code) +{ + *code = ~(DIV_ROUND_CLOSEST(gain, LTC6373_CONVERSION_CONSTANT) + 3) + & LTC6373_CONVERSION_MASK; + return 0; +} + +static int code_to_gain_dB(struct hmc425a_state *st, int *val, int *val2) +{ + if (st->powerdown) + return -EPERM; + return st->chip_info->code_to_gain_dB(st->gain, val, val2); +} + +static int hmc425a_code_to_gain_dB(int code, int *val, int *val2) +{ + *val = (~code * -500) / 1000; + *val2 = ((~code * -500) % 1000) * 1000; + return 0; +} + +static int hmc540s_code_to_gain_dB(int code, int *val, int *val2) +{ + *val = (~code * -1000) / 1000; + *val2 = ((~code * -1000) % 1000) * 1000; + return 0; +} + +static int adrf5740_code_to_gain_dB(int code, int *val, int *val2) +{ + /* + * Bit [0-3]: 2dB 4dB 8dB 8dB + * When BIT(3) is set, unset BIT(2) and use 3 as double the place value + */ + code = code & BIT(3) ? code & ~BIT(2) : code; + *val = (code * -2000) / 1000; + *val2 = ((code * -2000) % 1000) * 1000; + return 0; +} + +static int ltc6373_code_to_gain_dB(int code, int *val, int *val2) +{ + int gain = ((~code & LTC6373_CONVERSION_MASK) - 3) * + LTC6373_CONVERSION_CONSTANT; + + *val = gain / 1000; + *val2 = (gain % 1000) * 1000; + return 0; +} + +static int hmc425a_write(struct iio_dev *indio_dev, u32 value) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + DECLARE_BITMAP(values, BITS_PER_TYPE(value)); + + values[0] = value; + + gpiod_multi_set_value_cansleep(st->gpios, values); + return 0; +} + +static int hmc425a_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long m) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + int ret; + + mutex_lock(&st->lock); + switch (m) { + case IIO_CHAN_INFO_HARDWAREGAIN: + ret = code_to_gain_dB(st, val, val2); + if (ret) + break; + ret = IIO_VAL_INT_PLUS_MICRO_DB; + break; + default: + ret = -EINVAL; + } + mutex_unlock(&st->lock); + + return ret; +}; + +static int hmc425a_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int val, + int val2, long mask) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + int code = 0, ret; + + mutex_lock(&st->lock); + switch (mask) { + case IIO_CHAN_INFO_HARDWAREGAIN: + ret = gain_dB_to_code(st, val, val2, &code); + if (ret) + break; + st->gain = code; + + ret = hmc425a_write(indio_dev, st->gain); + break; + default: + ret = -EINVAL; + } + mutex_unlock(&st->lock); + + return ret; +} + +static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_HARDWAREGAIN: + return IIO_VAL_INT_PLUS_MICRO_DB; + default: + return -EINVAL; + } +} + +static const struct iio_info hmc425a_info = { + .read_raw = &hmc425a_read_raw, + .write_raw = &hmc425a_write_raw, + .write_raw_get_fmt = &hmc425a_write_raw_get_fmt, +}; + +static ssize_t ltc6373_read_powerdown(struct iio_dev *indio_dev, + uintptr_t private, + const struct iio_chan_spec *chan, + char *buf) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + + return sysfs_emit(buf, "%d\n", st->powerdown); +} + +static ssize_t ltc6373_write_powerdown(struct iio_dev *indio_dev, + uintptr_t private, + const struct iio_chan_spec *chan, + const char *buf, + size_t len) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + bool powerdown; + int code, ret; + + ret = kstrtobool(buf, &powerdown); + if (ret) + return ret; + + mutex_lock(&st->lock); + st->powerdown = powerdown; + code = (powerdown) ? LTC6373_SHUTDOWN : st->gain; + hmc425a_write(indio_dev, code); + mutex_unlock(&st->lock); + return len; +} + +static const struct iio_chan_spec_ext_info ltc6373_ext_info[] = { + { + .name = "powerdown", + .read = ltc6373_read_powerdown, + .write = ltc6373_write_powerdown, + .shared = IIO_SEPARATE, + }, + { } +}; + +#define HMC425A_CHAN(_channel) \ +{ \ + .type = IIO_VOLTAGE, \ + .output = 1, \ + .indexed = 1, \ + .channel = _channel, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ +} + +#define LTC6373_CHAN(_channel) \ +{ \ + .type = IIO_VOLTAGE, \ + .output = 1, \ + .indexed = 1, \ + .channel = _channel, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ + .ext_info = ltc6373_ext_info, \ +} + +static const struct iio_chan_spec hmc425a_channels[] = { + HMC425A_CHAN(0), +}; + +static const struct iio_chan_spec ltc6373_channels[] = { + LTC6373_CHAN(0), +}; + +static const struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { + [ID_HMC425A] = { + .name = "hmc425a", + .channels = hmc425a_channels, + .num_channels = ARRAY_SIZE(hmc425a_channels), + .num_gpios = 6, + .gain_min = -31500, + .gain_max = 0, + .default_gain = -0x40, /* set default gain -31.5db*/ + .gain_dB_to_code = hmc425a_gain_dB_to_code, + .code_to_gain_dB = hmc425a_code_to_gain_dB, + }, + [ID_HMC540S] = { + .name = "hmc540s", + .channels = hmc425a_channels, + .num_channels = ARRAY_SIZE(hmc425a_channels), + .num_gpios = 4, + .gain_min = -15000, + .gain_max = 0, + .default_gain = -0x10, /* set default gain -15.0db*/ + .gain_dB_to_code = hmc540s_gain_dB_to_code, + .code_to_gain_dB = hmc540s_code_to_gain_dB, + }, + [ID_ADRF5740] = { + .name = "adrf5740", + .channels = hmc425a_channels, + .num_channels = ARRAY_SIZE(hmc425a_channels), + .num_gpios = 4, + .gain_min = -22000, + .gain_max = 0, + .default_gain = 0xF, /* set default gain -22.0db*/ + .gain_dB_to_code = adrf5740_gain_dB_to_code, + .code_to_gain_dB = adrf5740_code_to_gain_dB, + }, + [ID_LTC6373] = { + .name = "ltc6373", + .channels = ltc6373_channels, + .num_channels = ARRAY_SIZE(ltc6373_channels), + .num_gpios = 3, + .gain_min = -12041, /* gain setting x0.25*/ + .gain_max = 24082, /* gain setting x16 */ + .default_gain = LTC6373_MIN_GAIN_CODE, + .powerdown_val = LTC6373_SHUTDOWN, + .has_powerdown = true, + .gain_dB_to_code = ltc6373_gain_dB_to_code, + .code_to_gain_dB = ltc6373_code_to_gain_dB, + }, +}; + +static int hmc425a_probe(struct platform_device *pdev) +{ + struct iio_dev *indio_dev; + struct hmc425a_state *st; + int ret; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + + st->chip_info = device_get_match_data(&pdev->dev); + indio_dev->num_channels = st->chip_info->num_channels; + indio_dev->channels = st->chip_info->channels; + indio_dev->name = st->chip_info->name; + st->gain = st->chip_info->default_gain; + + st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW); + if (IS_ERR(st->gpios)) + return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios), + "failed to get gpios\n"); + + if (st->gpios->ndescs != st->chip_info->num_gpios) { + dev_err(&pdev->dev, "%d GPIOs needed to operate\n", + st->chip_info->num_gpios); + return -ENODEV; + } + + ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply"); + if (ret) + return ret; + + mutex_init(&st->lock); + + indio_dev->info = &hmc425a_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + if (st->chip_info->has_powerdown) { + st->powerdown = true; + hmc425a_write(indio_dev, st->chip_info->powerdown_val); + } else { + /* Set default gain */ + hmc425a_write(indio_dev, st->gain); + } + + return devm_iio_device_register(&pdev->dev, indio_dev); +} + +static const struct of_device_id hmc425a_of_match[] = { + { .compatible = "adi,hmc425a", + .data = &hmc425a_chip_info_tbl[ID_HMC425A]}, + { .compatible = "adi,hmc540s", + .data = &hmc425a_chip_info_tbl[ID_HMC540S]}, + { .compatible = "adi,adrf5740", + .data = &hmc425a_chip_info_tbl[ID_ADRF5740]}, + { .compatible = "adi,ltc6373", + .data = &hmc425a_chip_info_tbl[ID_LTC6373]}, + { } +}; +MODULE_DEVICE_TABLE(of, hmc425a_of_match); + +static struct platform_driver hmc425a_driver = { + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = hmc425a_of_match, + }, + .probe = hmc425a_probe, +}; +module_platform_driver(hmc425a_driver); + +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); +MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers"); +MODULE_LICENSE("GPL v2"); |