diff options
Diffstat (limited to 'drivers/iio/amplifiers/hmc425a.c')
| -rw-r--r-- | drivers/iio/amplifiers/hmc425a.c | 274 |
1 files changed, 216 insertions, 58 deletions
diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc425a.c index ed4d7292269619..2ee4c0d70281e2 100644 --- a/drivers/iio/amplifiers/hmc425a.c +++ b/drivers/iio/amplifiers/hmc425a.c @@ -2,9 +2,10 @@ /* * HMC425A and similar Gain Amplifiers * - * Copyright 2020 Analog Devices Inc. + * Copyright 2020, 2024 Analog Devices Inc. */ +#include <linux/bits.h> #include <linux/bitops.h> #include <linux/device.h> #include <linux/err.h> @@ -12,6 +13,7 @@ #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> @@ -20,10 +22,24 @@ #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_ADRF5740, + ID_LTC6373, }; struct hmc425a_chip_info { @@ -34,16 +50,110 @@ struct hmc425a_chip_info { 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 */ - struct hmc425a_chip_info *chip_info; + const struct hmc425a_chip_info *chip_info; struct gpio_descs *gpios; - enum hmc425a_type type; 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); @@ -61,30 +171,14 @@ static int hmc425a_read_raw(struct iio_dev *indio_dev, int *val2, long m) { struct hmc425a_state *st = iio_priv(indio_dev); - int code, gain = 0; int ret; mutex_lock(&st->lock); switch (m) { case IIO_CHAN_INFO_HARDWAREGAIN: - code = st->gain; - - switch (st->type) { - case ID_HMC425A: - gain = ~code * -500; + ret = code_to_gain_dB(st, val, val2); + if (ret) break; - case ID_HMC540S: - gain = ~code * -1000; - break; - case ID_ADRF5740: - code = code & BIT(3) ? code & ~BIT(2) : code; - gain = code * -2000; - break; - } - - *val = gain / 1000; - *val2 = (gain % 1000) * 1000; - ret = IIO_VAL_INT_PLUS_MICRO_DB; break; default: @@ -100,34 +194,14 @@ static int hmc425a_write_raw(struct iio_dev *indio_dev, int val2, long mask) { struct hmc425a_state *st = iio_priv(indio_dev); - struct hmc425a_chip_info *inf = st->chip_info; - int code = 0, gain; - int ret; - - 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; - - switch (st->type) { - case ID_HMC425A: - code = ~((abs(gain) / 500) & 0x3F); - break; - case ID_HMC540S: - code = ~((abs(gain) / 1000) & 0xF); - break; - case ID_ADRF5740: - code = (abs(gain) / 2000) & 0xF; - code = code & BIT(3) ? code | BIT(2) : code; - break; - } + 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); @@ -158,6 +232,48 @@ static const struct iio_info hmc425a_info = { .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, \ @@ -167,20 +283,25 @@ static const struct iio_info hmc425a_info = { .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), }; -/* Match table for of_platform binding */ -static const struct of_device_id hmc425a_of_match[] = { - { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A }, - { .compatible = "adi,hmc540s", .data = (void *)ID_HMC540S }, - { .compatible = "adi,adrf5740", .data = (void *)ID_ADRF5740 }, - {}, +static const struct iio_chan_spec ltc6373_channels[] = { + LTC6373_CHAN(0), }; -MODULE_DEVICE_TABLE(of, hmc425a_of_match); -static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { +static const struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { [ID_HMC425A] = { .name = "hmc425a", .channels = hmc425a_channels, @@ -189,6 +310,8 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { .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", @@ -198,6 +321,8 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { .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", @@ -207,6 +332,21 @@ static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { .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, }, }; @@ -221,9 +361,8 @@ static int hmc425a_probe(struct platform_device *pdev) return -ENOMEM; st = iio_priv(indio_dev); - st->type = (uintptr_t)device_get_match_data(&pdev->dev); - st->chip_info = &hmc425a_chip_info_tbl[st->type]; + 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; @@ -249,12 +388,31 @@ static int hmc425a_probe(struct platform_device *pdev) indio_dev->info = &hmc425a_info; indio_dev->modes = INDIO_DIRECT_MODE; - /* Set default gain */ - hmc425a_write(indio_dev, st->gain); + 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); } +/* Match table for of_platform binding */ +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, |