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- // SPDX-License-Identifier: GPL-2.0
- /*
- * HMC425A and similar Gain Amplifiers
- *
- * Copyright 2020 Analog Devices Inc.
- */
- #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/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>
- enum hmc425a_type {
- ID_HMC425A,
- };
- 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;
- };
- struct hmc425a_state {
- struct regulator *reg;
- struct mutex lock; /* protect sensor state */
- struct hmc425a_chip_info *chip_info;
- struct gpio_descs *gpios;
- enum hmc425a_type type;
- u32 gain;
- };
- 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_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
- NULL, 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 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;
- break;
- }
- *val = gain / 1000;
- *val2 = (gain % 1000) * 1000;
- 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);
- 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;
- }
- mutex_lock(&st->lock);
- switch (mask) {
- case IIO_CHAN_INFO_HARDWAREGAIN:
- 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,
- };
- #define HMC425A_CHAN(_channel) \
- { \
- .type = IIO_VOLTAGE, \
- .output = 1, \
- .indexed = 1, \
- .channel = _channel, \
- .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
- }
- 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 },
- {},
- };
- MODULE_DEVICE_TABLE(of, hmc425a_of_match);
- static void hmc425a_reg_disable(void *data)
- {
- struct hmc425a_state *st = data;
- regulator_disable(st->reg);
- }
- static 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*/
- },
- };
- 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->type = (uintptr_t)device_get_match_data(&pdev->dev);
- st->chip_info = &hmc425a_chip_info_tbl[st->type];
- 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;
- }
- st->reg = devm_regulator_get(&pdev->dev, "vcc-supply");
- if (IS_ERR(st->reg))
- return PTR_ERR(st->reg);
- ret = regulator_enable(st->reg);
- if (ret)
- return ret;
- ret = devm_add_action_or_reset(&pdev->dev, hmc425a_reg_disable, st);
- if (ret)
- return ret;
- mutex_init(&st->lock);
- indio_dev->info = &hmc425a_info;
- indio_dev->modes = INDIO_DIRECT_MODE;
- return devm_iio_device_register(&pdev->dev, indio_dev);
- }
- 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 <[email protected]>");
- MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
- MODULE_LICENSE("GPL v2");
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