diff options
Diffstat (limited to 'drivers/iio/adc/ltc2497-core.c')
| -rw-r--r-- | drivers/iio/adc/ltc2497-core.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/drivers/iio/adc/ltc2497-core.c b/drivers/iio/adc/ltc2497-core.c new file mode 100644 index 000000000..2a485c8a1 --- /dev/null +++ b/drivers/iio/adc/ltc2497-core.c @@ -0,0 +1,238 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ltc2497-core.c - Common code for Analog Devices/Linear Technology + * LTC2496 and LTC2497 ADCs + * + * Copyright (C) 2017 Analog Devices Inc. + */ + +#include <linux/delay.h> +#include <linux/iio/iio.h> +#include <linux/iio/driver.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> + +#include "ltc2497.h" + +#define LTC2497_SGL BIT(4) +#define LTC2497_DIFF 0 +#define LTC2497_SIGN BIT(3) + +static int ltc2497core_wait_conv(struct ltc2497core_driverdata *ddata) +{ + s64 time_elapsed; + + time_elapsed = ktime_ms_delta(ktime_get(), ddata->time_prev); + + if (time_elapsed < LTC2497_CONVERSION_TIME_MS) { + /* delay if conversion time not passed + * since last read or write + */ + if (msleep_interruptible( + LTC2497_CONVERSION_TIME_MS - time_elapsed)) + return -ERESTARTSYS; + + return 0; + } + + if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) { + /* We're in automatic mode - + * so the last reading is still not outdated + */ + return 0; + } + + return 1; +} + +static int ltc2497core_read(struct ltc2497core_driverdata *ddata, u8 address, int *val) +{ + int ret; + + ret = ltc2497core_wait_conv(ddata); + if (ret < 0) + return ret; + + if (ret || ddata->addr_prev != address) { + ret = ddata->result_and_measure(ddata, address, NULL); + if (ret < 0) + return ret; + ddata->addr_prev = address; + + if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS)) + return -ERESTARTSYS; + } + + ret = ddata->result_and_measure(ddata, address, val); + if (ret < 0) + return ret; + + ddata->time_prev = ktime_get(); + + return ret; +} + +static int ltc2497core_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct ltc2497core_driverdata *ddata = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&indio_dev->mlock); + ret = ltc2497core_read(ddata, chan->address, val); + mutex_unlock(&indio_dev->mlock); + if (ret < 0) + return ret; + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + ret = regulator_get_voltage(ddata->ref); + if (ret < 0) + return ret; + + *val = ret / 1000; + *val2 = 17; + + return IIO_VAL_FRACTIONAL_LOG2; + + default: + return -EINVAL; + } +} + +#define LTC2497_CHAN(_chan, _addr, _ds_name) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_chan), \ + .address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .datasheet_name = (_ds_name), \ +} + +#define LTC2497_CHAN_DIFF(_chan, _addr) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \ + .channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\ + .address = (_addr | _chan), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .differential = 1, \ +} + +static const struct iio_chan_spec ltc2497core_channel[] = { + LTC2497_CHAN(0, LTC2497_SGL, "CH0"), + LTC2497_CHAN(1, LTC2497_SGL, "CH1"), + LTC2497_CHAN(2, LTC2497_SGL, "CH2"), + LTC2497_CHAN(3, LTC2497_SGL, "CH3"), + LTC2497_CHAN(4, LTC2497_SGL, "CH4"), + LTC2497_CHAN(5, LTC2497_SGL, "CH5"), + LTC2497_CHAN(6, LTC2497_SGL, "CH6"), + LTC2497_CHAN(7, LTC2497_SGL, "CH7"), + LTC2497_CHAN(8, LTC2497_SGL, "CH8"), + LTC2497_CHAN(9, LTC2497_SGL, "CH9"), + LTC2497_CHAN(10, LTC2497_SGL, "CH10"), + LTC2497_CHAN(11, LTC2497_SGL, "CH11"), + LTC2497_CHAN(12, LTC2497_SGL, "CH12"), + LTC2497_CHAN(13, LTC2497_SGL, "CH13"), + LTC2497_CHAN(14, LTC2497_SGL, "CH14"), + LTC2497_CHAN(15, LTC2497_SGL, "CH15"), + LTC2497_CHAN_DIFF(0, LTC2497_DIFF), + LTC2497_CHAN_DIFF(1, LTC2497_DIFF), + LTC2497_CHAN_DIFF(2, LTC2497_DIFF), + LTC2497_CHAN_DIFF(3, LTC2497_DIFF), + LTC2497_CHAN_DIFF(4, LTC2497_DIFF), + LTC2497_CHAN_DIFF(5, LTC2497_DIFF), + LTC2497_CHAN_DIFF(6, LTC2497_DIFF), + LTC2497_CHAN_DIFF(7, LTC2497_DIFF), + LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN), + LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN), +}; + +static const struct iio_info ltc2497core_info = { + .read_raw = ltc2497core_read_raw, +}; + +int ltc2497core_probe(struct device *dev, struct iio_dev *indio_dev) +{ + struct ltc2497core_driverdata *ddata = iio_priv(indio_dev); + int ret; + + indio_dev->name = dev_name(dev); + indio_dev->info = <c2497core_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ltc2497core_channel; + indio_dev->num_channels = ARRAY_SIZE(ltc2497core_channel); + + ret = ddata->result_and_measure(ddata, LTC2497_CONFIG_DEFAULT, NULL); + if (ret < 0) + return ret; + + ddata->ref = devm_regulator_get(dev, "vref"); + if (IS_ERR(ddata->ref)) + return dev_err_probe(dev, PTR_ERR(ddata->ref), + "Failed to get vref regulator\n"); + + ret = regulator_enable(ddata->ref); + if (ret < 0) { + dev_err(dev, "Failed to enable vref regulator: %pe\n", + ERR_PTR(ret)); + return ret; + } + + if (dev->platform_data) { + struct iio_map *plat_data; + + plat_data = (struct iio_map *)dev->platform_data; + + ret = iio_map_array_register(indio_dev, plat_data); + if (ret) { + dev_err(&indio_dev->dev, "iio map err: %d\n", ret); + goto err_regulator_disable; + } + } + + ddata->addr_prev = LTC2497_CONFIG_DEFAULT; + ddata->time_prev = ktime_get(); + + ret = iio_device_register(indio_dev); + if (ret < 0) + goto err_array_unregister; + + return 0; + +err_array_unregister: + iio_map_array_unregister(indio_dev); + +err_regulator_disable: + regulator_disable(ddata->ref); + + return ret; +} +EXPORT_SYMBOL_NS(ltc2497core_probe, LTC2497); + +void ltc2497core_remove(struct iio_dev *indio_dev) +{ + struct ltc2497core_driverdata *ddata = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + + iio_map_array_unregister(indio_dev); + + regulator_disable(ddata->ref); +} +EXPORT_SYMBOL_NS(ltc2497core_remove, LTC2497); + +MODULE_DESCRIPTION("common code for LTC2496/LTC2497 drivers"); +MODULE_LICENSE("GPL v2"); |