// SPDX-License-Identifier: GPL-2.0-or-later /* * A sensor driver for the magnetometer AK8975. * * Magnetic compass sensor driver for monitoring magnetic flux information. * * Copyright (c) 2010, NVIDIA Corporation. */ #include <linux/module.h> #include <linux/mod_devicetable.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/i2c.h> #include <linux/interrupt.h> #include <linux/err.h> #include <linux/mutex.h> #include <linux/delay.h> #include <linux/bitops.h> #include <linux/gpio/consumer.h> #include <linux/regulator/consumer.h> #include <linux/pm_runtime.h> #include <linux/iio/iio.h> #include <linux/iio/sysfs.h> #include <linux/iio/buffer.h> #include <linux/iio/trigger.h> #include <linux/iio/trigger_consumer.h> #include <linux/iio/triggered_buffer.h> /* * Register definitions, as well as various shifts and masks to get at the * individual fields of the registers. */ #define AK8975_REG_WIA … #define AK8975_DEVICE_ID … #define AK8975_REG_INFO … #define AK8975_REG_ST1 … #define AK8975_REG_ST1_DRDY_SHIFT … #define AK8975_REG_ST1_DRDY_MASK … #define AK8975_REG_HXL … #define AK8975_REG_HXH … #define AK8975_REG_HYL … #define AK8975_REG_HYH … #define AK8975_REG_HZL … #define AK8975_REG_HZH … #define AK8975_REG_ST2 … #define AK8975_REG_ST2_DERR_SHIFT … #define AK8975_REG_ST2_DERR_MASK … #define AK8975_REG_ST2_HOFL_SHIFT … #define AK8975_REG_ST2_HOFL_MASK … #define AK8975_REG_CNTL … #define AK8975_REG_CNTL_MODE_SHIFT … #define AK8975_REG_CNTL_MODE_MASK … #define AK8975_REG_CNTL_MODE_POWER_DOWN … #define AK8975_REG_CNTL_MODE_ONCE … #define AK8975_REG_CNTL_MODE_SELF_TEST … #define AK8975_REG_CNTL_MODE_FUSE_ROM … #define AK8975_REG_RSVC … #define AK8975_REG_ASTC … #define AK8975_REG_TS1 … #define AK8975_REG_TS2 … #define AK8975_REG_I2CDIS … #define AK8975_REG_ASAX … #define AK8975_REG_ASAY … #define AK8975_REG_ASAZ … #define AK8975_MAX_REGS … /* * AK09912 Register definitions */ #define AK09912_REG_WIA1 … #define AK09912_REG_WIA2 … #define AK09918_DEVICE_ID … #define AK09916_DEVICE_ID … #define AK09912_DEVICE_ID … #define AK09911_DEVICE_ID … #define AK09911_REG_INFO1 … #define AK09911_REG_INFO2 … #define AK09912_REG_ST1 … #define AK09912_REG_ST1_DRDY_SHIFT … #define AK09912_REG_ST1_DRDY_MASK … #define AK09912_REG_HXL … #define AK09912_REG_HXH … #define AK09912_REG_HYL … #define AK09912_REG_HYH … #define AK09912_REG_HZL … #define AK09912_REG_HZH … #define AK09912_REG_TMPS … #define AK09912_REG_ST2 … #define AK09912_REG_ST2_HOFL_SHIFT … #define AK09912_REG_ST2_HOFL_MASK … #define AK09912_REG_CNTL1 … #define AK09912_REG_CNTL2 … #define AK09912_REG_CNTL_MODE_POWER_DOWN … #define AK09912_REG_CNTL_MODE_ONCE … #define AK09912_REG_CNTL_MODE_SELF_TEST … #define AK09912_REG_CNTL_MODE_FUSE_ROM … #define AK09912_REG_CNTL2_MODE_SHIFT … #define AK09912_REG_CNTL2_MODE_MASK … #define AK09912_REG_CNTL3 … #define AK09912_REG_TS1 … #define AK09912_REG_TS2 … #define AK09912_REG_TS3 … #define AK09912_REG_I2CDIS … #define AK09912_REG_TS4 … #define AK09912_REG_ASAX … #define AK09912_REG_ASAY … #define AK09912_REG_ASAZ … #define AK09912_MAX_REGS … /* * Miscellaneous values. */ #define AK8975_MAX_CONVERSION_TIMEOUT … #define AK8975_CONVERSION_DONE_POLL_TIME … #define AK8975_DATA_READY_TIMEOUT … /* * Precalculate scale factor (in Gauss units) for each axis and * store in the device data. * * This scale factor is axis-dependent, and is derived from 3 calibration * factors ASA(x), ASA(y), and ASA(z). * * These ASA values are read from the sensor device at start of day, and * cached in the device context struct. * * Adjusting the flux value with the sensitivity adjustment value should be * done via the following formula: * * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 ) * where H is the raw value, ASA is the sensitivity adjustment, and Hadj * is the resultant adjusted value. * * We reduce the formula to: * * Hadj = H * (ASA + 128) / 256 * * H is in the range of -4096 to 4095. The magnetometer has a range of * +-1229uT. To go from the raw value to uT is: * * HuT = H * 1229/4096, or roughly, 3/10. * * Since 1uT = 0.01 gauss, our final scale factor becomes: * * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100 * Hadj = H * ((ASA + 128) * 0.003) / 256 * * Since ASA doesn't change, we cache the resultant scale factor into the * device context in ak8975_setup(). * * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we * multiply the stored scale value by 1e6. */ static long ak8975_raw_to_gauss(u16 data) { … } /* * For AK8963 and AK09911, same calculation, but the device is less sensitive: * * H is in the range of +-8190. The magnetometer has a range of * +-4912uT. To go from the raw value to uT is: * * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10. */ static long ak8963_09911_raw_to_gauss(u16 data) { … } /* * For AK09912, same calculation, except the device is more sensitive: * * H is in the range of -32752 to 32752. The magnetometer has a range of * +-4912uT. To go from the raw value to uT is: * * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10. */ static long ak09912_raw_to_gauss(u16 data) { … } /* Compatible Asahi Kasei Compass parts */ enum asahi_compass_chipset { … }; enum ak_ctrl_reg_addr { … }; enum ak_ctrl_reg_mask { … }; enum ak_ctrl_mode { … }; struct ak_def { … }; static const struct ak_def ak_def_array[] = …; /* * Per-instance context data for the device. */ struct ak8975_data { … }; /* Enable attached power regulator if any. */ static int ak8975_power_on(const struct ak8975_data *data) { … } /* Disable attached power regulator if any. */ static void ak8975_power_off(const struct ak8975_data *data) { … } /* * Return 0 if the i2c device is the one we expect. * return a negative error number otherwise */ static int ak8975_who_i_am(struct i2c_client *client, enum asahi_compass_chipset type) { … } /* * Helper function to write to CNTL register. */ static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode) { … } /* * Handle data ready irq */ static irqreturn_t ak8975_irq_handler(int irq, void *data) { … } /* * Install data ready interrupt handler */ static int ak8975_setup_irq(struct ak8975_data *data) { … } /* * Perform some start-of-day setup, including reading the asa calibration * values and caching them. */ static int ak8975_setup(struct i2c_client *client) { … } static int wait_conversion_complete_gpio(struct ak8975_data *data) { … } static int wait_conversion_complete_polled(struct ak8975_data *data) { … } /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */ static int wait_conversion_complete_interrupt(struct ak8975_data *data) { … } static int ak8975_start_read_axis(struct ak8975_data *data, const struct i2c_client *client) { … } /* Retrieve raw flux value for one of the x, y, or z axis. */ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) { … } static int ak8975_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { … } static const struct iio_mount_matrix * ak8975_get_mount_matrix(const struct iio_dev *indio_dev, const struct iio_chan_spec *chan) { … } static const struct iio_chan_spec_ext_info ak8975_ext_info[] = …; #define AK8975_CHANNEL(axis, index) … static const struct iio_chan_spec ak8975_channels[] = …; static const unsigned long ak8975_scan_masks[] = …; static const struct iio_info ak8975_info = …; static void ak8975_fill_buffer(struct iio_dev *indio_dev) { … } static irqreturn_t ak8975_handle_trigger(int irq, void *p) { … } static int ak8975_probe(struct i2c_client *client) { … } static void ak8975_remove(struct i2c_client *client) { … } static int ak8975_runtime_suspend(struct device *dev) { … } static int ak8975_runtime_resume(struct device *dev) { … } static DEFINE_RUNTIME_DEV_PM_OPS(ak8975_dev_pm_ops, ak8975_runtime_suspend, ak8975_runtime_resume, NULL); static const struct acpi_device_id ak_acpi_match[] = …; MODULE_DEVICE_TABLE(acpi, ak_acpi_match); static const struct i2c_device_id ak8975_id[] = …; MODULE_DEVICE_TABLE(i2c, ak8975_id); static const struct of_device_id ak8975_of_match[] = …; MODULE_DEVICE_TABLE(of, ak8975_of_match); static struct i2c_driver ak8975_driver = …; module_i2c_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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