diff options
Diffstat (limited to 'drivers/iio/adc/hi8435.c')
| -rw-r--r-- | drivers/iio/adc/hi8435.c | 568 |
1 files changed, 568 insertions, 0 deletions
diff --git a/drivers/iio/adc/hi8435.c b/drivers/iio/adc/hi8435.c new file mode 100644 index 000000000..6f6c9a348 --- /dev/null +++ b/drivers/iio/adc/hi8435.c @@ -0,0 +1,568 @@ +/* + * Holt Integrated Circuits HI-8435 threshold detector driver + * + * Copyright (C) 2015 Zodiac Inflight Innovations + * Copyright (C) 2015 Cogent Embedded, Inc. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ + +#include <linux/delay.h> +#include <linux/iio/events.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_event.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_gpio.h> +#include <linux/spi/spi.h> +#include <linux/gpio/consumer.h> + +#define DRV_NAME "hi8435" + +/* Register offsets for HI-8435 */ +#define HI8435_CTRL_REG 0x02 +#define HI8435_PSEN_REG 0x04 +#define HI8435_TMDATA_REG 0x1E +#define HI8435_GOCENHYS_REG 0x3A +#define HI8435_SOCENHYS_REG 0x3C +#define HI8435_SO7_0_REG 0x10 +#define HI8435_SO15_8_REG 0x12 +#define HI8435_SO23_16_REG 0x14 +#define HI8435_SO31_24_REG 0x16 +#define HI8435_SO31_0_REG 0x78 + +#define HI8435_WRITE_OPCODE 0x00 +#define HI8435_READ_OPCODE 0x80 + +/* CTRL register bits */ +#define HI8435_CTRL_TEST 0x01 +#define HI8435_CTRL_SRST 0x02 + +struct hi8435_priv { + struct spi_device *spi; + struct mutex lock; + + unsigned long event_scan_mask; /* soft mask/unmask channels events */ + unsigned int event_prev_val; + + unsigned threshold_lo[2]; /* GND-Open and Supply-Open thresholds */ + unsigned threshold_hi[2]; /* GND-Open and Supply-Open thresholds */ + u8 reg_buffer[3] ____cacheline_aligned; +}; + +static int hi8435_readb(struct hi8435_priv *priv, u8 reg, u8 *val) +{ + reg |= HI8435_READ_OPCODE; + return spi_write_then_read(priv->spi, ®, 1, val, 1); +} + +static int hi8435_readw(struct hi8435_priv *priv, u8 reg, u16 *val) +{ + int ret; + __be16 be_val; + + reg |= HI8435_READ_OPCODE; + ret = spi_write_then_read(priv->spi, ®, 1, &be_val, 2); + *val = be16_to_cpu(be_val); + + return ret; +} + +static int hi8435_readl(struct hi8435_priv *priv, u8 reg, u32 *val) +{ + int ret; + __be32 be_val; + + reg |= HI8435_READ_OPCODE; + ret = spi_write_then_read(priv->spi, ®, 1, &be_val, 4); + *val = be32_to_cpu(be_val); + + return ret; +} + +static int hi8435_writeb(struct hi8435_priv *priv, u8 reg, u8 val) +{ + priv->reg_buffer[0] = reg | HI8435_WRITE_OPCODE; + priv->reg_buffer[1] = val; + + return spi_write(priv->spi, priv->reg_buffer, 2); +} + +static int hi8435_writew(struct hi8435_priv *priv, u8 reg, u16 val) +{ + priv->reg_buffer[0] = reg | HI8435_WRITE_OPCODE; + priv->reg_buffer[1] = (val >> 8) & 0xff; + priv->reg_buffer[2] = val & 0xff; + + return spi_write(priv->spi, priv->reg_buffer, 3); +} + +static int hi8435_read_raw(struct iio_dev *idev, + const struct iio_chan_spec *chan, + int *val, int *val2, long mask) +{ + struct hi8435_priv *priv = iio_priv(idev); + u32 tmp; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp); + if (ret < 0) + return ret; + *val = !!(tmp & BIT(chan->channel)); + return IIO_VAL_INT; + default: + return -EINVAL; + } +} + +static int hi8435_read_event_config(struct iio_dev *idev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir) +{ + struct hi8435_priv *priv = iio_priv(idev); + + return !!(priv->event_scan_mask & BIT(chan->channel)); +} + +static int hi8435_write_event_config(struct iio_dev *idev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, int state) +{ + struct hi8435_priv *priv = iio_priv(idev); + int ret; + u32 tmp; + + if (state) { + ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp); + if (ret < 0) + return ret; + if (tmp & BIT(chan->channel)) + priv->event_prev_val |= BIT(chan->channel); + else + priv->event_prev_val &= ~BIT(chan->channel); + + priv->event_scan_mask |= BIT(chan->channel); + } else + priv->event_scan_mask &= ~BIT(chan->channel); + + return 0; +} + +static int hi8435_read_event_value(struct iio_dev *idev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, + int *val, int *val2) +{ + struct hi8435_priv *priv = iio_priv(idev); + int ret; + u8 mode, psen; + u16 reg; + + ret = hi8435_readb(priv, HI8435_PSEN_REG, &psen); + if (ret < 0) + return ret; + + /* Supply-Open or GND-Open sensing mode */ + mode = !!(psen & BIT(chan->channel / 8)); + + ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG : + HI8435_GOCENHYS_REG, ®); + if (ret < 0) + return ret; + + if (dir == IIO_EV_DIR_FALLING) + *val = ((reg & 0xff) - (reg >> 8)) / 2; + else if (dir == IIO_EV_DIR_RISING) + *val = ((reg & 0xff) + (reg >> 8)) / 2; + + return IIO_VAL_INT; +} + +static int hi8435_write_event_value(struct iio_dev *idev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, + int val, int val2) +{ + struct hi8435_priv *priv = iio_priv(idev); + int ret; + u8 mode, psen; + u16 reg; + + ret = hi8435_readb(priv, HI8435_PSEN_REG, &psen); + if (ret < 0) + return ret; + + /* Supply-Open or GND-Open sensing mode */ + mode = !!(psen & BIT(chan->channel / 8)); + + ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG : + HI8435_GOCENHYS_REG, ®); + if (ret < 0) + return ret; + + if (dir == IIO_EV_DIR_FALLING) { + /* falling threshold range 2..21V, hysteresis minimum 2V */ + if (val < 2 || val > 21 || (val + 2) > priv->threshold_hi[mode]) + return -EINVAL; + + if (val == priv->threshold_lo[mode]) + return 0; + + priv->threshold_lo[mode] = val; + + /* hysteresis must not be odd */ + if ((priv->threshold_hi[mode] - priv->threshold_lo[mode]) % 2) + priv->threshold_hi[mode]--; + } else if (dir == IIO_EV_DIR_RISING) { + /* rising threshold range 3..22V, hysteresis minimum 2V */ + if (val < 3 || val > 22 || val < (priv->threshold_lo[mode] + 2)) + return -EINVAL; + + if (val == priv->threshold_hi[mode]) + return 0; + + priv->threshold_hi[mode] = val; + + /* hysteresis must not be odd */ + if ((priv->threshold_hi[mode] - priv->threshold_lo[mode]) % 2) + priv->threshold_lo[mode]++; + } + + /* program thresholds */ + mutex_lock(&priv->lock); + + ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG : + HI8435_GOCENHYS_REG, ®); + if (ret < 0) { + mutex_unlock(&priv->lock); + return ret; + } + + /* hysteresis */ + reg = priv->threshold_hi[mode] - priv->threshold_lo[mode]; + reg <<= 8; + /* threshold center */ + reg |= (priv->threshold_hi[mode] + priv->threshold_lo[mode]); + + ret = hi8435_writew(priv, mode ? HI8435_SOCENHYS_REG : + HI8435_GOCENHYS_REG, reg); + + mutex_unlock(&priv->lock); + + return ret; +} + +static int hi8435_debugfs_reg_access(struct iio_dev *idev, + unsigned reg, unsigned writeval, + unsigned *readval) +{ + struct hi8435_priv *priv = iio_priv(idev); + int ret; + u8 val; + + if (readval != NULL) { + ret = hi8435_readb(priv, reg, &val); + *readval = val; + } else { + val = (u8)writeval; + ret = hi8435_writeb(priv, reg, val); + } + + return ret; +} + +static const struct iio_event_spec hi8435_events[] = { + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_RISING, + .mask_separate = BIT(IIO_EV_INFO_VALUE), + }, { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_FALLING, + .mask_separate = BIT(IIO_EV_INFO_VALUE), + }, { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_EITHER, + .mask_separate = BIT(IIO_EV_INFO_ENABLE), + }, +}; + +static int hi8435_get_sensing_mode(struct iio_dev *idev, + const struct iio_chan_spec *chan) +{ + struct hi8435_priv *priv = iio_priv(idev); + int ret; + u8 reg; + + ret = hi8435_readb(priv, HI8435_PSEN_REG, ®); + if (ret < 0) + return ret; + + return !!(reg & BIT(chan->channel / 8)); +} + +static int hi8435_set_sensing_mode(struct iio_dev *idev, + const struct iio_chan_spec *chan, + unsigned int mode) +{ + struct hi8435_priv *priv = iio_priv(idev); + int ret; + u8 reg; + + mutex_lock(&priv->lock); + + ret = hi8435_readb(priv, HI8435_PSEN_REG, ®); + if (ret < 0) { + mutex_unlock(&priv->lock); + return ret; + } + + reg &= ~BIT(chan->channel / 8); + if (mode) + reg |= BIT(chan->channel / 8); + + ret = hi8435_writeb(priv, HI8435_PSEN_REG, reg); + + mutex_unlock(&priv->lock); + + return ret; +} + +static const char * const hi8435_sensing_modes[] = { "GND-Open", + "Supply-Open" }; + +static const struct iio_enum hi8435_sensing_mode = { + .items = hi8435_sensing_modes, + .num_items = ARRAY_SIZE(hi8435_sensing_modes), + .get = hi8435_get_sensing_mode, + .set = hi8435_set_sensing_mode, +}; + +static const struct iio_chan_spec_ext_info hi8435_ext_info[] = { + IIO_ENUM("sensing_mode", IIO_SEPARATE, &hi8435_sensing_mode), + IIO_ENUM_AVAILABLE("sensing_mode", &hi8435_sensing_mode), + {}, +}; + +#define HI8435_VOLTAGE_CHANNEL(num) \ +{ \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = num, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .event_spec = hi8435_events, \ + .num_event_specs = ARRAY_SIZE(hi8435_events), \ + .ext_info = hi8435_ext_info, \ +} + +static const struct iio_chan_spec hi8435_channels[] = { + HI8435_VOLTAGE_CHANNEL(0), + HI8435_VOLTAGE_CHANNEL(1), + HI8435_VOLTAGE_CHANNEL(2), + HI8435_VOLTAGE_CHANNEL(3), + HI8435_VOLTAGE_CHANNEL(4), + HI8435_VOLTAGE_CHANNEL(5), + HI8435_VOLTAGE_CHANNEL(6), + HI8435_VOLTAGE_CHANNEL(7), + HI8435_VOLTAGE_CHANNEL(8), + HI8435_VOLTAGE_CHANNEL(9), + HI8435_VOLTAGE_CHANNEL(10), + HI8435_VOLTAGE_CHANNEL(11), + HI8435_VOLTAGE_CHANNEL(12), + HI8435_VOLTAGE_CHANNEL(13), + HI8435_VOLTAGE_CHANNEL(14), + HI8435_VOLTAGE_CHANNEL(15), + HI8435_VOLTAGE_CHANNEL(16), + HI8435_VOLTAGE_CHANNEL(17), + HI8435_VOLTAGE_CHANNEL(18), + HI8435_VOLTAGE_CHANNEL(19), + HI8435_VOLTAGE_CHANNEL(20), + HI8435_VOLTAGE_CHANNEL(21), + HI8435_VOLTAGE_CHANNEL(22), + HI8435_VOLTAGE_CHANNEL(23), + HI8435_VOLTAGE_CHANNEL(24), + HI8435_VOLTAGE_CHANNEL(25), + HI8435_VOLTAGE_CHANNEL(26), + HI8435_VOLTAGE_CHANNEL(27), + HI8435_VOLTAGE_CHANNEL(28), + HI8435_VOLTAGE_CHANNEL(29), + HI8435_VOLTAGE_CHANNEL(30), + HI8435_VOLTAGE_CHANNEL(31), + IIO_CHAN_SOFT_TIMESTAMP(32), +}; + +static const struct iio_info hi8435_info = { + .read_raw = hi8435_read_raw, + .read_event_config = hi8435_read_event_config, + .write_event_config = hi8435_write_event_config, + .read_event_value = hi8435_read_event_value, + .write_event_value = hi8435_write_event_value, + .debugfs_reg_access = hi8435_debugfs_reg_access, +}; + +static void hi8435_iio_push_event(struct iio_dev *idev, unsigned int val) +{ + struct hi8435_priv *priv = iio_priv(idev); + enum iio_event_direction dir; + unsigned int i; + unsigned int status = priv->event_prev_val ^ val; + + if (!status) + return; + + for_each_set_bit(i, &priv->event_scan_mask, 32) { + if (status & BIT(i)) { + dir = val & BIT(i) ? IIO_EV_DIR_RISING : + IIO_EV_DIR_FALLING; + iio_push_event(idev, + IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i, + IIO_EV_TYPE_THRESH, dir), + iio_get_time_ns(idev)); + } + } + + priv->event_prev_val = val; +} + +static irqreturn_t hi8435_trigger_handler(int irq, void *private) +{ + struct iio_poll_func *pf = private; + struct iio_dev *idev = pf->indio_dev; + struct hi8435_priv *priv = iio_priv(idev); + u32 val; + int ret; + + ret = hi8435_readl(priv, HI8435_SO31_0_REG, &val); + if (ret < 0) + goto err_read; + + hi8435_iio_push_event(idev, val); + +err_read: + iio_trigger_notify_done(idev->trig); + + return IRQ_HANDLED; +} + +static int hi8435_probe(struct spi_device *spi) +{ + struct iio_dev *idev; + struct hi8435_priv *priv; + struct gpio_desc *reset_gpio; + int ret; + + idev = devm_iio_device_alloc(&spi->dev, sizeof(*priv)); + if (!idev) + return -ENOMEM; + + priv = iio_priv(idev); + priv->spi = spi; + + reset_gpio = devm_gpiod_get(&spi->dev, NULL, GPIOD_OUT_LOW); + if (IS_ERR(reset_gpio)) { + /* chip s/w reset if h/w reset failed */ + hi8435_writeb(priv, HI8435_CTRL_REG, HI8435_CTRL_SRST); + hi8435_writeb(priv, HI8435_CTRL_REG, 0); + } else { + udelay(5); + gpiod_set_value(reset_gpio, 1); + } + + spi_set_drvdata(spi, idev); + mutex_init(&priv->lock); + + idev->dev.parent = &spi->dev; + idev->dev.of_node = spi->dev.of_node; + idev->name = spi_get_device_id(spi)->name; + idev->modes = INDIO_DIRECT_MODE; + idev->info = &hi8435_info; + idev->channels = hi8435_channels; + idev->num_channels = ARRAY_SIZE(hi8435_channels); + + /* unmask all events */ + priv->event_scan_mask = ~(0); + /* + * There is a restriction in the chip - the hysteresis can not be odd. + * If the hysteresis is set to odd value then chip gets into lock state + * and not functional anymore. + * After chip reset the thresholds are in undefined state, so we need to + * initialize thresholds to some initial values and then prevent + * userspace setting odd hysteresis. + * + * Set threshold low voltage to 2V, threshold high voltage to 4V + * for both GND-Open and Supply-Open sensing modes. + */ + priv->threshold_lo[0] = priv->threshold_lo[1] = 2; + priv->threshold_hi[0] = priv->threshold_hi[1] = 4; + hi8435_writew(priv, HI8435_GOCENHYS_REG, 0x206); + hi8435_writew(priv, HI8435_SOCENHYS_REG, 0x206); + + ret = iio_triggered_event_setup(idev, NULL, hi8435_trigger_handler); + if (ret) + return ret; + + ret = iio_device_register(idev); + if (ret < 0) { + dev_err(&spi->dev, "unable to register device\n"); + goto unregister_triggered_event; + } + + return 0; + +unregister_triggered_event: + iio_triggered_event_cleanup(idev); + return ret; +} + +static int hi8435_remove(struct spi_device *spi) +{ + struct iio_dev *idev = spi_get_drvdata(spi); + + iio_device_unregister(idev); + iio_triggered_event_cleanup(idev); + + return 0; +} + +static const struct of_device_id hi8435_dt_ids[] = { + { .compatible = "holt,hi8435" }, + {}, +}; +MODULE_DEVICE_TABLE(of, hi8435_dt_ids); + +static const struct spi_device_id hi8435_id[] = { + { "hi8435", 0}, + { } +}; +MODULE_DEVICE_TABLE(spi, hi8435_id); + +static struct spi_driver hi8435_driver = { + .driver = { + .name = DRV_NAME, + .of_match_table = of_match_ptr(hi8435_dt_ids), + }, + .probe = hi8435_probe, + .remove = hi8435_remove, + .id_table = hi8435_id, +}; +module_spi_driver(hi8435_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Vladimir Barinov"); +MODULE_DESCRIPTION("HI-8435 threshold detector"); |