diff options
Diffstat (limited to 'drivers/iio/adc/ti-lmp92064.c')
| -rw-r--r-- | drivers/iio/adc/ti-lmp92064.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti-lmp92064.c b/drivers/iio/adc/ti-lmp92064.c new file mode 100644 index 000000000000..c30ed824924f --- /dev/null +++ b/drivers/iio/adc/ti-lmp92064.c @@ -0,0 +1,332 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Texas Instruments LMP92064 SPI ADC driver + * + * Copyright (c) 2022 Leonard Göhrs <kernel@pengutronix.de>, Pengutronix + * + * Based on linux/drivers/iio/adc/ti-tsc2046.c + * Copyright (c) 2021 Oleksij Rempel <kernel@pengutronix.de>, Pengutronix + */ + +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/spi.h> + +#include <linux/iio/iio.h> +#include <linux/iio/driver.h> + +#define TI_LMP92064_REG_CONFIG_A 0x0000 +#define TI_LMP92064_REG_CONFIG_B 0x0001 +#define TI_LMP92064_REG_CHIP_REV 0x0006 + +#define TI_LMP92064_REG_MFR_ID1 0x000C +#define TI_LMP92064_REG_MFR_ID2 0x000D + +#define TI_LMP92064_REG_REG_UPDATE 0x000F +#define TI_LMP92064_REG_CONFIG_REG 0x0100 +#define TI_LMP92064_REG_STATUS 0x0103 + +#define TI_LMP92064_REG_DATA_VOUT_LSB 0x0200 +#define TI_LMP92064_REG_DATA_VOUT_MSB 0x0201 +#define TI_LMP92064_REG_DATA_COUT_LSB 0x0202 +#define TI_LMP92064_REG_DATA_COUT_MSB 0x0203 + +#define TI_LMP92064_VAL_CONFIG_A 0x99 +#define TI_LMP92064_VAL_CONFIG_B 0x00 +#define TI_LMP92064_VAL_STATUS_OK 0x01 + +/* + * Channel number definitions for the two channels of the device + * - IN Current (INC) + * - IN Voltage (INV) + */ +#define TI_LMP92064_CHAN_INC 0 +#define TI_LMP92064_CHAN_INV 1 + +static const struct regmap_range lmp92064_readable_reg_ranges[] = { + regmap_reg_range(TI_LMP92064_REG_CONFIG_A, TI_LMP92064_REG_CHIP_REV), + regmap_reg_range(TI_LMP92064_REG_MFR_ID1, TI_LMP92064_REG_MFR_ID2), + regmap_reg_range(TI_LMP92064_REG_REG_UPDATE, TI_LMP92064_REG_REG_UPDATE), + regmap_reg_range(TI_LMP92064_REG_CONFIG_REG, TI_LMP92064_REG_CONFIG_REG), + regmap_reg_range(TI_LMP92064_REG_STATUS, TI_LMP92064_REG_STATUS), + regmap_reg_range(TI_LMP92064_REG_DATA_VOUT_LSB, TI_LMP92064_REG_DATA_COUT_MSB), +}; + +static const struct regmap_access_table lmp92064_readable_regs = { + .yes_ranges = lmp92064_readable_reg_ranges, + .n_yes_ranges = ARRAY_SIZE(lmp92064_readable_reg_ranges), +}; + +static const struct regmap_range lmp92064_writable_reg_ranges[] = { + regmap_reg_range(TI_LMP92064_REG_CONFIG_A, TI_LMP92064_REG_CONFIG_B), + regmap_reg_range(TI_LMP92064_REG_REG_UPDATE, TI_LMP92064_REG_REG_UPDATE), + regmap_reg_range(TI_LMP92064_REG_CONFIG_REG, TI_LMP92064_REG_CONFIG_REG), +}; + +static const struct regmap_access_table lmp92064_writable_regs = { + .yes_ranges = lmp92064_writable_reg_ranges, + .n_yes_ranges = ARRAY_SIZE(lmp92064_writable_reg_ranges), +}; + +static const struct regmap_config lmp92064_spi_regmap_config = { + .reg_bits = 16, + .val_bits = 8, + .max_register = TI_LMP92064_REG_DATA_COUT_MSB, + .rd_table = &lmp92064_readable_regs, + .wr_table = &lmp92064_writable_regs, +}; + +struct lmp92064_adc_priv { + int shunt_resistor_uohm; + struct spi_device *spi; + struct regmap *regmap; +}; + +static const struct iio_chan_spec lmp92064_adc_channels[] = { + { + .type = IIO_CURRENT, + .address = TI_LMP92064_CHAN_INC, + .info_mask_separate = + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .datasheet_name = "INC", + }, + { + .type = IIO_VOLTAGE, + .address = TI_LMP92064_CHAN_INV, + .info_mask_separate = + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .datasheet_name = "INV", + }, +}; + +static int lmp92064_read_meas(struct lmp92064_adc_priv *priv, u16 *res) +{ + __be16 raw[2]; + int ret; + + /* + * The ADC only latches in new samples if all DATA registers are read + * in descending sequential order. + * The ADC auto-decrements the register index with each clocked byte. + * Read both channels in single SPI transfer by selecting the highest + * register using the command below and clocking out all four data + * bytes. + */ + + ret = regmap_bulk_read(priv->regmap, TI_LMP92064_REG_DATA_COUT_MSB, + &raw, sizeof(raw)); + + if (ret) { + dev_err(&priv->spi->dev, "regmap_bulk_read failed: %pe\n", + ERR_PTR(ret)); + return ret; + } + + res[0] = be16_to_cpu(raw[0]); + res[1] = be16_to_cpu(raw[1]); + + return 0; +} + +static int lmp92064_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + struct lmp92064_adc_priv *priv = iio_priv(indio_dev); + u16 raw[2]; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = lmp92064_read_meas(priv, raw); + if (ret < 0) + return ret; + + *val = (chan->address == TI_LMP92064_CHAN_INC) ? raw[0] : raw[1]; + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + if (chan->address == TI_LMP92064_CHAN_INC) { + /* + * processed (mA) = raw * current_lsb (mA) + * current_lsb (mA) = shunt_voltage_lsb (nV) / shunt_resistor (uOhm) + * shunt_voltage_lsb (nV) = 81920000 / 4096 = 20000 + */ + *val = 20000; + *val2 = priv->shunt_resistor_uohm; + } else { + /* + * processed (mV) = raw * voltage_lsb (mV) + * voltage_lsb (mV) = 2048 / 4096 + */ + *val = 2048; + *val2 = 4096; + } + return IIO_VAL_FRACTIONAL; + default: + return -EINVAL; + } +} + +static int lmp92064_reset(struct lmp92064_adc_priv *priv, + struct gpio_desc *gpio_reset) +{ + unsigned int status; + int ret, i; + + if (gpio_reset) { + /* + * Perform a hard reset if gpio_reset is available. + * The datasheet specifies a very low 3.5ns reset pulse duration and does not + * specify how long to wait after a reset to access the device. + * Use more conservative pulse lengths to allow analog RC filtering of the + * reset line at the board level (as recommended in the datasheet). + */ + gpiod_set_value_cansleep(gpio_reset, 1); + usleep_range(1, 10); + gpiod_set_value_cansleep(gpio_reset, 0); + usleep_range(500, 750); + } else { + /* + * Perform a soft-reset if not. + * Also write default values to the config registers that are not + * affected by soft reset. + */ + ret = regmap_write(priv->regmap, TI_LMP92064_REG_CONFIG_A, + TI_LMP92064_VAL_CONFIG_A); + if (ret < 0) + return ret; + + ret = regmap_write(priv->regmap, TI_LMP92064_REG_CONFIG_B, + TI_LMP92064_VAL_CONFIG_B); + if (ret < 0) + return ret; + } + + /* + * Wait for the device to signal readiness to prevent reading bogus data + * and make sure device is actually connected. + * The datasheet does not specify how long this takes but usually it is + * not more than 3-4 iterations of this loop. + */ + for (i = 0; i < 10; i++) { + ret = regmap_read(priv->regmap, TI_LMP92064_REG_STATUS, &status); + if (ret < 0) + return ret; + + if (status == TI_LMP92064_VAL_STATUS_OK) + return 0; + + usleep_range(1000, 2000); + } + + /* + * No (correct) response received. + * Device is mostly likely not connected to the bus. + */ + return -ENXIO; +} + +static const struct iio_info lmp92064_adc_info = { + .read_raw = lmp92064_read_raw, +}; + +static int lmp92064_adc_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct lmp92064_adc_priv *priv; + struct gpio_desc *gpio_reset; + struct iio_dev *indio_dev; + u32 shunt_resistor_uohm; + struct regmap *regmap; + int ret; + + ret = spi_setup(spi); + if (ret < 0) + return dev_err_probe(dev, ret, "Error in SPI setup\n"); + + regmap = devm_regmap_init_spi(spi, &lmp92064_spi_regmap_config); + if (IS_ERR(regmap)) + return dev_err_probe(dev, PTR_ERR(regmap), + "Failed to set up SPI regmap\n"); + + indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); + if (!indio_dev) + return -ENOMEM; + + priv = iio_priv(indio_dev); + + priv->spi = spi; + priv->regmap = regmap; + + ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", + &shunt_resistor_uohm); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to get shunt-resistor value\n"); + + /* + * The shunt resistance is passed to userspace as the denominator of an iio + * fraction. Make sure it is in range for that. + */ + if (shunt_resistor_uohm == 0 || shunt_resistor_uohm > INT_MAX) { + dev_err(dev, "Shunt resistance is out of range\n"); + return -EINVAL; + } + + priv->shunt_resistor_uohm = shunt_resistor_uohm; + + ret = devm_regulator_get_enable(dev, "vdd"); + if (ret) + return ret; + + ret = devm_regulator_get_enable(dev, "vdig"); + if (ret) + return ret; + + gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(gpio_reset)) + return dev_err_probe(dev, PTR_ERR(gpio_reset), + "Failed to get GPIO reset pin\n"); + + ret = lmp92064_reset(priv, gpio_reset); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to reset device\n"); + + indio_dev->name = "lmp92064"; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = lmp92064_adc_channels; + indio_dev->num_channels = ARRAY_SIZE(lmp92064_adc_channels); + indio_dev->info = &lmp92064_adc_info; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct spi_device_id lmp92064_id_table[] = { + { "lmp92064" }, + {} +}; +MODULE_DEVICE_TABLE(spi, lmp92064_id_table); + +static const struct of_device_id lmp92064_of_table[] = { + { .compatible = "ti,lmp92064" }, + {} +}; +MODULE_DEVICE_TABLE(of, lmp92064_of_table); + +static struct spi_driver lmp92064_adc_driver = { + .driver = { + .name = "lmp92064", + .of_match_table = lmp92064_of_table, + }, + .probe = lmp92064_adc_probe, + .id_table = lmp92064_id_table, +}; +module_spi_driver(lmp92064_adc_driver); + +MODULE_AUTHOR("Leonard Göhrs <kernel@pengutronix.de>"); +MODULE_DESCRIPTION("TI LMP92064 ADC"); +MODULE_LICENSE("GPL"); |