--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ROHM ADC driver for BD79112 signal monitoring hub.
+ * Copyright (C) 2025, ROHM Semiconductor.
+ *
+ * SPI communication derived from ad7923.c and ti-ads7950.c
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/gpio/driver.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+#include <linux/iio/adc-helpers.h>
+#include <linux/iio/iio.h>
+
+#define BD79112_MAX_NUM_CHANNELS 32
+
+struct bd79112_data {
+ struct spi_device *spi;
+ struct regmap *map;
+ struct device *dev;
+ struct gpio_chip gc;
+ unsigned long gpio_valid_mask;
+ unsigned int vref_mv;
+ struct spi_transfer read_xfer[2];
+ struct spi_transfer write_xfer;
+ struct spi_message read_msg;
+ struct spi_message write_msg;
+ /* 16-bit TX, valid data in high byte */
+ u8 read_tx[2] __aligned(IIO_DMA_MINALIGN);
+ /* 8-bit address followed by 8-bit data */
+ u8 reg_write_tx[2];
+ /* 12-bit of ADC data or 8 bit of reg data */
+ __be16 read_rx;
+};
+
+/*
+ * The ADC data is read issuing SPI-command matching the channel number.
+ * We treat this as a register address.
+ */
+#define BD79112_REG_AGIO0A 0x00
+#define BD79112_REG_AGIO15B 0x1f
+
+/*
+ * ADC STATUS_FLAG appended to ADC data will be set, if the ADC result is being
+ * read for a channel, which input pin is muxed to be a GPIO.
+ */
+#define BD79112_ADC_STATUS_FLAG BIT(14)
+
+/*
+ * The BD79112 requires "R/W bit" to be set for SPI register (not ADC data)
+ * reads and an "IOSET bit" to be set for read/write operations (which aren't
+ * reading the ADC data).
+ */
+#define BD79112_BIT_RW BIT(4)
+#define BD79112_BIT_IO BIT(5)
+
+#define BD79112_REG_GPI_VALUE_B8_15 (BD79112_BIT_IO | 0x0)
+#define BD79112_REG_GPI_VALUE_B0_B7 (BD79112_BIT_IO | 0x1)
+#define BD79112_REG_GPI_VALUE_A8_15 (BD79112_BIT_IO | 0x2)
+#define BD79112_REG_GPI_VALUE_A0_A7 (BD79112_BIT_IO | 0x3)
+
+#define BD79112_REG_GPI_EN_B7_B15 (BD79112_BIT_IO | 0x4)
+#define BD79112_REG_GPI_EN_B0_B7 (BD79112_BIT_IO | 0x5)
+#define BD79112_REG_GPI_EN_A8_A15 (BD79112_BIT_IO | 0x6)
+#define BD79112_REG_GPI_EN_A0_A7 (BD79112_BIT_IO | 0x7)
+
+#define BD79112_REG_GPO_EN_B7_B15 (BD79112_BIT_IO | 0x8)
+#define BD79112_REG_GPO_EN_B0_B7 (BD79112_BIT_IO | 0x9)
+#define BD79112_REG_GPO_EN_A8_A15 (BD79112_BIT_IO | 0xa)
+#define BD79112_REG_GPO_EN_A0_A7 (BD79112_BIT_IO | 0xb)
+
+#define BD79112_NUM_GPIO_EN_REGS 8
+#define BD79112_FIRST_GPIO_EN_REG BD79112_REG_GPI_EN_B7_B15
+
+#define BD79112_REG_GPO_VALUE_B8_15 (BD79112_BIT_IO | 0xc)
+#define BD79112_REG_GPO_VALUE_B0_B7 (BD79112_BIT_IO | 0xd)
+#define BD79112_REG_GPO_VALUE_A8_15 (BD79112_BIT_IO | 0xe)
+#define BD79112_REG_GPO_VALUE_A0_A7 (BD79112_BIT_IO | 0xf)
+
+#define BD79112_REG_MAX BD79112_REG_GPO_VALUE_A0_A7
+
+/*
+ * Read transaction consists of two 16-bit sequences separated by CSB.
+ * For register read, 'IOSET' bit must be set. For ADC read, IOSET is cleared
+ * and ADDR equals the channel number (0 ... 31).
+ *
+ * First 16-bit sequence, MOSI as below, MISO data ignored:
+ * - SCK: | 1 | 2 | 3 | 4 | 5 .. 8 | 9 .. 16 |
+ * - MOSI:| 0 | 0 | IOSET | RW (1) | ADDR | 8'b0 |
+ *
+ * CSB released and re-acquired between these sequences
+ *
+ * Second 16-bit sequence, MISO as below, MOSI data ignored:
+ * For Register read data is 8 bits:
+ * - SCK: | 1 .. 8 | 9 .. 16 |
+ * - MISO:| 8'b0 | 8-bit data |
+ *
+ * For ADC read data is 12 bits:
+ * - SCK: | 1 | 2 | 3 4 | 4 .. 16 |
+ * - MISO:| 0 | STATUS_FLAG | 2'b0 | 12-bit data |
+ * The 'STATUS_FLAG' is set if the read input pin was configured as a GPIO.
+ */
+static int bd79112_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+ struct bd79112_data *data = context;
+ int ret;
+
+ if (reg & BD79112_BIT_IO)
+ reg |= BD79112_BIT_RW;
+
+ data->read_tx[0] = reg;
+
+ ret = spi_sync(data->spi, &data->read_msg);
+ if (!ret)
+ *val = be16_to_cpu(data->read_rx);
+
+ return ret;
+}
+
+/*
+ * Write, single 16-bit sequence (broken down below):
+ *
+ * First 8-bit, MOSI as below, MISO data ignored:
+ * - SCK: | 1 | 2 | 3 | 4 | 5 .. 8 |
+ * - MOSI:| 0 | 0 |IOSET| RW(0) | ADDR |
+ *
+ * Last 8 SCK cycles (b8 ... b15), MISO contains register data, MOSI ignored.
+ * - SCK: | 9 .. 16 |
+ * - MISO:| data |
+ */
+static int bd79112_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+ struct bd79112_data *data = context;
+
+ data->reg_write_tx[0] = reg;
+ data->reg_write_tx[1] = val;
+
+ return spi_sync(data->spi, &data->write_msg);
+}
+
+static int _get_gpio_reg(unsigned int offset, unsigned int base)
+{
+ int regoffset = offset / 8;
+
+ if (offset > 31)
+ return -EINVAL;
+
+ return base - regoffset;
+}
+
+#define GET_GPIO_BIT(offset) BIT((offset) % 8)
+#define GET_GPO_EN_REG(offset) _get_gpio_reg((offset), BD79112_REG_GPO_EN_A0_A7)
+#define GET_GPI_EN_REG(offset) _get_gpio_reg((offset), BD79112_REG_GPI_EN_A0_A7)
+#define GET_GPO_VAL_REG(offset) _get_gpio_reg((offset), BD79112_REG_GPO_VALUE_A0_A7)
+#define GET_GPI_VAL_REG(offset) _get_gpio_reg((offset), BD79112_REG_GPI_VALUE_A0_A7)
+
+static const struct regmap_range bd71815_volatile_ro_ranges[] = {
+ {
+ /* Read ADC data */
+ .range_min = BD79112_REG_AGIO0A,
+ .range_max = BD79112_REG_AGIO15B,
+ }, {
+ /* GPI state */
+ .range_min = BD79112_REG_GPI_VALUE_B8_15,
+ .range_max = BD79112_REG_GPI_VALUE_A0_A7,
+ },
+};
+
+static const struct regmap_access_table bd79112_volatile_regs = {
+ .yes_ranges = &bd71815_volatile_ro_ranges[0],
+ .n_yes_ranges = ARRAY_SIZE(bd71815_volatile_ro_ranges),
+};
+
+static const struct regmap_access_table bd79112_ro_regs = {
+ .no_ranges = &bd71815_volatile_ro_ranges[0],
+ .n_no_ranges = ARRAY_SIZE(bd71815_volatile_ro_ranges),
+};
+
+static const struct regmap_config bd79112_regmap = {
+ .reg_read = bd79112_reg_read,
+ .reg_write = bd79112_reg_write,
+ .volatile_table = &bd79112_volatile_regs,
+ .wr_table = &bd79112_ro_regs,
+ .cache_type = REGCACHE_MAPLE,
+ .max_register = BD79112_REG_MAX,
+};
+
+static int bd79112_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val,
+ int *val2, long m)
+{
+ struct bd79112_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ ret = regmap_read(data->map, chan->channel, val);
+ if (ret < 0)
+ return ret;
+
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = data->vref_mv;
+ *val2 = 12;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info bd79112_info = {
+ .read_raw = bd79112_read_raw,
+};
+
+static const struct iio_chan_spec bd79112_chan_template = {
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ .indexed = 1,
+};
+
+static int bd79112_gpio_init_valid_mask(struct gpio_chip *gc,
+ unsigned long *valid_mask,
+ unsigned int ngpios)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+
+ *valid_mask = data->gpio_valid_mask;
+
+ return 0;
+}
+
+static int bd79112_gpio_dir_get(struct gpio_chip *gc, unsigned int offset)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+ unsigned int reg, bit, val;
+ int ret;
+
+ bit = GET_GPIO_BIT(offset);
+ reg = GET_GPO_EN_REG(offset);
+
+ ret = regmap_read(data->map, reg, &val);
+ if (ret)
+ return ret;
+
+ if (bit & val)
+ return GPIO_LINE_DIRECTION_OUT;
+
+ reg = GET_GPI_EN_REG(offset);
+ ret = regmap_read(data->map, reg, &val);
+ if (ret)
+ return ret;
+
+ if (bit & val)
+ return GPIO_LINE_DIRECTION_IN;
+
+ /*
+ * Ouch. Seems the pin is ADC input - shouldn't happen as changing mux
+ * at runtime is not supported and non GPIO pins should be invalidated
+ * by the valid_mask at probe. Maybe someone wrote a register bypassing
+ * the driver?
+ */
+ dev_err(data->dev, "Pin not a GPIO\n");
+
+ return -EINVAL;
+}
+
+static int bd79112_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+ unsigned int reg, bit, val;
+ int ret;
+
+ bit = GET_GPIO_BIT(offset);
+ reg = GET_GPI_VAL_REG(offset);
+
+ ret = regmap_read(data->map, reg, &val);
+ if (ret)
+ return ret;
+
+ return !!(val & bit);
+}
+
+static int bd79112_gpio_set(struct gpio_chip *gc, unsigned int offset,
+ int value)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+ unsigned int reg, bit;
+
+ bit = GET_GPIO_BIT(offset);
+ reg = GET_GPO_VAL_REG(offset);
+
+ return regmap_assign_bits(data->map, reg, bit, value);
+}
+
+static int bd79112_gpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+ unsigned long i, bank_mask;
+
+ for_each_set_clump8(i, bank_mask, mask, gc->ngpio) {
+ unsigned long bank_bits;
+ unsigned int reg;
+ int ret;
+
+ bank_bits = bitmap_get_value8(bits, i);
+ reg = BD79112_REG_GPO_VALUE_A0_A7 - i / 8;
+ ret = regmap_update_bits(data->map, reg, bank_mask, bank_bits);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int bd79112_gpio_dir_set(struct bd79112_data *data, unsigned int offset,
+ int dir)
+{
+ unsigned int gpi_reg, gpo_reg, bit;
+ int ret;
+
+ bit = GET_GPIO_BIT(offset);
+ gpi_reg = GET_GPI_EN_REG(offset);
+ gpo_reg = GET_GPO_EN_REG(offset);
+
+ if (dir == GPIO_LINE_DIRECTION_OUT) {
+ ret = regmap_clear_bits(data->map, gpi_reg, bit);
+ if (ret)
+ return ret;
+
+ return regmap_set_bits(data->map, gpo_reg, bit);
+ }
+
+ ret = regmap_set_bits(data->map, gpi_reg, bit);
+ if (ret)
+ return ret;
+
+ return regmap_clear_bits(data->map, gpo_reg, bit);
+}
+
+static int bd79112_gpio_input(struct gpio_chip *gc, unsigned int offset)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+
+ return bd79112_gpio_dir_set(data, offset, GPIO_LINE_DIRECTION_IN);
+}
+
+static int bd79112_gpio_output(struct gpio_chip *gc, unsigned int offset,
+ int value)
+{
+ struct bd79112_data *data = gpiochip_get_data(gc);
+ int ret;
+
+ ret = bd79112_gpio_set(gc, offset, value);
+ if (ret)
+ return ret;
+
+ return bd79112_gpio_dir_set(data, offset, GPIO_LINE_DIRECTION_OUT);
+}
+
+static const struct gpio_chip bd79112_gpio_chip = {
+ .label = "bd79112-gpio",
+ .get_direction = bd79112_gpio_dir_get,
+ .direction_input = bd79112_gpio_input,
+ .direction_output = bd79112_gpio_output,
+ .get = bd79112_gpio_get,
+ .set = bd79112_gpio_set,
+ .set_multiple = bd79112_gpio_set_multiple,
+ .init_valid_mask = bd79112_gpio_init_valid_mask,
+ .can_sleep = true,
+ .ngpio = 32,
+ .base = -1,
+};
+
+static unsigned int bd79112_get_gpio_pins(const struct iio_chan_spec *cs, int num_channels)
+{
+ unsigned int i, gpio_channels;
+
+ /*
+ * Let's initialize the mux config to say that all 32 channels are
+ * GPIOs. Then we can just loop through the iio_chan_spec and clear the
+ * bits for found ADC channels.
+ */
+ gpio_channels = GENMASK(31, 0);
+ for (i = 0; i < num_channels; i++)
+ gpio_channels &= ~BIT(cs[i].channel);
+
+ return gpio_channels;
+}
+
+/* ADC channels as named in the data-sheet */
+static const char * const bd79112_chan_names[] = {
+ "AGIO0A", "AGIO1A", "AGIO2A", "AGIO3A", /* 0 - 3 */
+ "AGIO4A", "AGIO5A", "AGIO6A", "AGIO7A", /* 4 - 7 */
+ "AGIO8A", "AGIO9A", "AGIO10A", "AGIO11A", /* 8 - 11 */
+ "AGIO12A", "AGIO13A", "AGIO14A", "AGIO15A", /* 12 - 15 */
+ "AGIO0B", "AGIO1B", "AGIO2B", "AGIO3B", /* 16 - 19 */
+ "AGIO4B", "AGIO5B", "AGIO6B", "AGIO7B", /* 20 - 23 */
+ "AGIO8B", "AGIO9B", "AGIO10B", "AGIO11B", /* 24 - 27 */
+ "AGIO12B", "AGIO13B", "AGIO14B", "AGIO15B", /* 28 - 31 */
+};
+
+static int bd79112_probe(struct spi_device *spi)
+{
+ struct bd79112_data *data;
+ struct iio_dev *iio_dev;
+ struct iio_chan_spec *cs;
+ struct device *dev = &spi->dev;
+ unsigned long gpio_pins, pin;
+ unsigned int i;
+ int ret;
+
+ iio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!iio_dev)
+ return -ENOMEM;
+
+ data = iio_priv(iio_dev);
+ data->spi = spi;
+ data->dev = dev;
+ data->map = devm_regmap_init(dev, NULL, data, &bd79112_regmap);
+ if (IS_ERR(data->map))
+ return dev_err_probe(dev, PTR_ERR(data->map),
+ "Failed to initialize Regmap\n");
+
+ ret = devm_regulator_get_enable_read_voltage(dev, "vdd");
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to get the Vdd\n");
+
+ data->vref_mv = ret / 1000;
+
+ ret = devm_regulator_get_enable(dev, "iovdd");
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to enable I/O voltage\n");
+
+ data->read_xfer[0].tx_buf = &data->read_tx[0];
+ data->read_xfer[0].len = sizeof(data->read_tx);
+ data->read_xfer[0].cs_change = 1;
+ data->read_xfer[1].rx_buf = &data->read_rx;
+ data->read_xfer[1].len = sizeof(data->read_rx);
+ spi_message_init_with_transfers(&data->read_msg, data->read_xfer, 2);
+ ret = devm_spi_optimize_message(dev, spi, &data->read_msg);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "Failed to optimize SPI read message\n");
+
+ data->write_xfer.tx_buf = &data->reg_write_tx[0];
+ data->write_xfer.len = sizeof(data->reg_write_tx);
+ spi_message_init_with_transfers(&data->write_msg, &data->write_xfer, 1);
+ ret = devm_spi_optimize_message(dev, spi, &data->write_msg);
+ if (ret < 0)
+ return dev_err_probe(dev, ret,
+ "Failed to optimize SPI write message\n");
+
+ ret = devm_iio_adc_device_alloc_chaninfo_se(dev, &bd79112_chan_template,
+ BD79112_MAX_NUM_CHANNELS - 1,
+ &cs);
+
+ /* Register all pins as GPIOs if there are no ADC channels */
+ if (ret == -ENOENT)
+ goto register_gpios;
+
+ if (ret < 0)
+ return ret;
+
+ iio_dev->num_channels = ret;
+ iio_dev->channels = cs;
+
+ for (i = 0; i < iio_dev->num_channels; i++)
+ cs[i].datasheet_name = bd79112_chan_names[cs[i].channel];
+
+ iio_dev->info = &bd79112_info;
+ iio_dev->name = "bd79112";
+ iio_dev->modes = INDIO_DIRECT_MODE;
+
+ /*
+ * Ensure all channels are ADCs. This allows us to register the IIO
+ * device early (before checking which pins are to be used for GPIO)
+ * without having to worry about some pins being initially used for
+ * GPIO.
+ */
+ for (i = 0; i < BD79112_NUM_GPIO_EN_REGS; i++) {
+ ret = regmap_write(data->map, BD79112_FIRST_GPIO_EN_REG + i, 0);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to initialize channels\n");
+ }
+
+ ret = devm_iio_device_register(data->dev, iio_dev);
+ if (ret)
+ return dev_err_probe(data->dev, ret, "Failed to register ADC\n");
+
+register_gpios:
+ gpio_pins = bd79112_get_gpio_pins(iio_dev->channels,
+ iio_dev->num_channels);
+
+ /* If all channels are reserved for ADC, then we're done. */
+ if (!gpio_pins)
+ return 0;
+
+ /* Default all the GPIO pins to GPI */
+ for_each_set_bit(pin, &gpio_pins, BD79112_MAX_NUM_CHANNELS) {
+ ret = bd79112_gpio_dir_set(data, pin, GPIO_LINE_DIRECTION_IN);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to mark pin as GPI\n");
+ }
+
+ data->gpio_valid_mask = gpio_pins;
+ data->gc = bd79112_gpio_chip;
+ data->gc.parent = dev;
+
+ return devm_gpiochip_add_data(dev, &data->gc, data);
+}
+
+static const struct of_device_id bd79112_of_match[] = {
+ { .compatible = "rohm,bd79112" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, bd79112_of_match);
+
+static const struct spi_device_id bd79112_id[] = {
+ { "bd79112" },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, bd79112_id);
+
+static struct spi_driver bd79112_driver = {
+ .driver = {
+ .name = "bd79112",
+ .of_match_table = bd79112_of_match,
+ },
+ .probe = bd79112_probe,
+ .id_table = bd79112_id,
+};
+module_spi_driver(bd79112_driver);
+
+MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>");
+MODULE_DESCRIPTION("Driver for ROHM BD79112 ADC/GPIO");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("IIO_DRIVER");
projects / thirdparty / linux.git / commitdiff
