diff options
Diffstat (limited to 'drivers/iio/light/st_uvis25_core.c')
| -rw-r--r-- | drivers/iio/light/st_uvis25_core.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/drivers/iio/light/st_uvis25_core.c b/drivers/iio/light/st_uvis25_core.c new file mode 100644 index 000000000000..302635836e6b --- /dev/null +++ b/drivers/iio/light/st_uvis25_core.c @@ -0,0 +1,359 @@ +/* + * STMicroelectronics uvis25 sensor driver + * + * Copyright 2017 STMicroelectronics Inc. + * + * Lorenzo Bianconi <lorenzo.bianconi83@gmail.com> + * + * Licensed under the GPL-2. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/iio/sysfs.h> +#include <linux/delay.h> +#include <linux/pm.h> +#include <linux/interrupt.h> +#include <linux/irqreturn.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/buffer.h> +#include <linux/regmap.h> + +#include "st_uvis25.h" + +#define ST_UVIS25_REG_WHOAMI_ADDR 0x0f +#define ST_UVIS25_REG_WHOAMI_VAL 0xca +#define ST_UVIS25_REG_CTRL1_ADDR 0x20 +#define ST_UVIS25_REG_ODR_MASK BIT(0) +#define ST_UVIS25_REG_BDU_MASK BIT(1) +#define ST_UVIS25_REG_CTRL2_ADDR 0x21 +#define ST_UVIS25_REG_BOOT_MASK BIT(7) +#define ST_UVIS25_REG_CTRL3_ADDR 0x22 +#define ST_UVIS25_REG_HL_MASK BIT(7) +#define ST_UVIS25_REG_STATUS_ADDR 0x27 +#define ST_UVIS25_REG_UV_DA_MASK BIT(0) +#define ST_UVIS25_REG_OUT_ADDR 0x28 + +static const struct iio_chan_spec st_uvis25_channels[] = { + { + .type = IIO_UVINDEX, + .address = ST_UVIS25_REG_OUT_ADDR, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .scan_index = 0, + .scan_type = { + .sign = 'u', + .realbits = 8, + .storagebits = 8, + }, + }, + IIO_CHAN_SOFT_TIMESTAMP(1), +}; + +static int st_uvis25_check_whoami(struct st_uvis25_hw *hw) +{ + int err, data; + + err = regmap_read(hw->regmap, ST_UVIS25_REG_WHOAMI_ADDR, &data); + if (err < 0) { + dev_err(regmap_get_device(hw->regmap), + "failed to read whoami register\n"); + return err; + } + + if (data != ST_UVIS25_REG_WHOAMI_VAL) { + dev_err(regmap_get_device(hw->regmap), + "wrong whoami {%02x vs %02x}\n", + data, ST_UVIS25_REG_WHOAMI_VAL); + return -ENODEV; + } + + return 0; +} + +static int st_uvis25_set_enable(struct st_uvis25_hw *hw, bool enable) +{ + int err; + + err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR, + ST_UVIS25_REG_ODR_MASK, enable); + if (err < 0) + return err; + + hw->enabled = enable; + + return 0; +} + +static int st_uvis25_read_oneshot(struct st_uvis25_hw *hw, u8 addr, int *val) +{ + int err; + + err = st_uvis25_set_enable(hw, true); + if (err < 0) + return err; + + msleep(1500); + + /* + * in order to avoid possible race conditions with interrupt + * generation, disable the sensor first and then poll output + * register. That sequence guarantees the interrupt will be reset + * when irq line is unmasked + */ + err = st_uvis25_set_enable(hw, false); + if (err < 0) + return err; + + err = regmap_read(hw->regmap, addr, val); + + return err < 0 ? err : IIO_VAL_INT; +} + +static int st_uvis25_read_raw(struct iio_dev *iio_dev, + struct iio_chan_spec const *ch, + int *val, int *val2, long mask) +{ + int ret; + + ret = iio_device_claim_direct_mode(iio_dev); + if (ret) + return ret; + + switch (mask) { + case IIO_CHAN_INFO_PROCESSED: { + struct st_uvis25_hw *hw = iio_priv(iio_dev); + + /* + * mask irq line during oneshot read since the sensor + * does not export the capability to disable data-ready line + * in the register map and it is enabled by default. + * If the line is unmasked during read_raw() it will be set + * active and never reset since the trigger is disabled + */ + if (hw->irq > 0) + disable_irq(hw->irq); + ret = st_uvis25_read_oneshot(hw, ch->address, val); + if (hw->irq > 0) + enable_irq(hw->irq); + break; + } + default: + ret = -EINVAL; + break; + } + + iio_device_release_direct_mode(iio_dev); + + return ret; +} + +static irqreturn_t st_uvis25_trigger_handler_thread(int irq, void *private) +{ + struct st_uvis25_hw *hw = private; + int err, status; + + err = regmap_read(hw->regmap, ST_UVIS25_REG_STATUS_ADDR, &status); + if (err < 0) + return IRQ_HANDLED; + + if (!(status & ST_UVIS25_REG_UV_DA_MASK)) + return IRQ_NONE; + + iio_trigger_poll_chained(hw->trig); + + return IRQ_HANDLED; +} + +static int st_uvis25_allocate_trigger(struct iio_dev *iio_dev) +{ + struct st_uvis25_hw *hw = iio_priv(iio_dev); + struct device *dev = regmap_get_device(hw->regmap); + bool irq_active_low = false; + unsigned long irq_type; + int err; + + irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq)); + + switch (irq_type) { + case IRQF_TRIGGER_HIGH: + case IRQF_TRIGGER_RISING: + break; + case IRQF_TRIGGER_LOW: + case IRQF_TRIGGER_FALLING: + irq_active_low = true; + break; + default: + dev_info(dev, "mode %lx unsupported\n", irq_type); + return -EINVAL; + } + + err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL3_ADDR, + ST_UVIS25_REG_HL_MASK, irq_active_low); + if (err < 0) + return err; + + err = devm_request_threaded_irq(dev, hw->irq, NULL, + st_uvis25_trigger_handler_thread, + irq_type | IRQF_ONESHOT, + iio_dev->name, hw); + if (err) { + dev_err(dev, "failed to request trigger irq %d\n", + hw->irq); + return err; + } + + hw->trig = devm_iio_trigger_alloc(dev, "%s-trigger", + iio_dev->name); + if (!hw->trig) + return -ENOMEM; + + iio_trigger_set_drvdata(hw->trig, iio_dev); + hw->trig->dev.parent = dev; + + return devm_iio_trigger_register(dev, hw->trig); +} + +static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev) +{ + return st_uvis25_set_enable(iio_priv(iio_dev), true); +} + +static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev) +{ + return st_uvis25_set_enable(iio_priv(iio_dev), false); +} + +static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = { + .preenable = st_uvis25_buffer_preenable, + .postenable = iio_triggered_buffer_postenable, + .predisable = iio_triggered_buffer_predisable, + .postdisable = st_uvis25_buffer_postdisable, +}; + +static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p) +{ + u8 buffer[ALIGN(sizeof(u8), sizeof(s64)) + sizeof(s64)]; + struct iio_poll_func *pf = p; + struct iio_dev *iio_dev = pf->indio_dev; + struct st_uvis25_hw *hw = iio_priv(iio_dev); + int err; + + err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer); + if (err < 0) + goto out; + + iio_push_to_buffers_with_timestamp(iio_dev, buffer, + iio_get_time_ns(iio_dev)); + +out: + iio_trigger_notify_done(hw->trig); + + return IRQ_HANDLED; +} + +static int st_uvis25_allocate_buffer(struct iio_dev *iio_dev) +{ + struct st_uvis25_hw *hw = iio_priv(iio_dev); + + return devm_iio_triggered_buffer_setup(regmap_get_device(hw->regmap), + iio_dev, NULL, + st_uvis25_buffer_handler_thread, + &st_uvis25_buffer_ops); +} + +static const struct iio_info st_uvis25_info = { + .read_raw = st_uvis25_read_raw, +}; + +static int st_uvis25_init_sensor(struct st_uvis25_hw *hw) +{ + int err; + + err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL2_ADDR, + ST_UVIS25_REG_BOOT_MASK, 1); + if (err < 0) + return err; + + msleep(2000); + + return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR, + ST_UVIS25_REG_BDU_MASK, 1); +} + +int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap) +{ + struct st_uvis25_hw *hw; + struct iio_dev *iio_dev; + int err; + + iio_dev = devm_iio_device_alloc(dev, sizeof(*hw)); + if (!iio_dev) + return -ENOMEM; + + dev_set_drvdata(dev, (void *)iio_dev); + + hw = iio_priv(iio_dev); + hw->irq = irq; + hw->regmap = regmap; + + err = st_uvis25_check_whoami(hw); + if (err < 0) + return err; + + iio_dev->modes = INDIO_DIRECT_MODE; + iio_dev->dev.parent = dev; + iio_dev->channels = st_uvis25_channels; + iio_dev->num_channels = ARRAY_SIZE(st_uvis25_channels); + iio_dev->name = ST_UVIS25_DEV_NAME; + iio_dev->info = &st_uvis25_info; + + err = st_uvis25_init_sensor(hw); + if (err < 0) + return err; + + if (hw->irq > 0) { + err = st_uvis25_allocate_buffer(iio_dev); + if (err < 0) + return err; + + err = st_uvis25_allocate_trigger(iio_dev); + if (err) + return err; + } + + return devm_iio_device_register(dev, iio_dev); +} +EXPORT_SYMBOL(st_uvis25_probe); + +static int __maybe_unused st_uvis25_suspend(struct device *dev) +{ + struct iio_dev *iio_dev = dev_get_drvdata(dev); + struct st_uvis25_hw *hw = iio_priv(iio_dev); + + return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR, + ST_UVIS25_REG_ODR_MASK, 0); +} + +static int __maybe_unused st_uvis25_resume(struct device *dev) +{ + struct iio_dev *iio_dev = dev_get_drvdata(dev); + struct st_uvis25_hw *hw = iio_priv(iio_dev); + + if (hw->enabled) + return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR, + ST_UVIS25_REG_ODR_MASK, 1); + + return 0; +} + +const struct dev_pm_ops st_uvis25_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(st_uvis25_suspend, st_uvis25_resume) +}; +EXPORT_SYMBOL(st_uvis25_pm_ops); + +MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>"); +MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver"); +MODULE_LICENSE("GPL v2"); |