/* * A sensor driver for the magnetometer AK8975. * * Magnetic compass sensor driver for monitoring magnetic flux information. * * Copyright (c) 2010, NVIDIA Corporation. * * 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. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Register definitions, as well as various shifts and masks to get at the * individual fields of the registers. */ #define AK8975_REG_WIA 0x00 #define AK8975_DEVICE_ID 0x48 #define AK8975_REG_INFO 0x01 #define AK8975_REG_ST1 0x02 #define AK8975_REG_ST1_DRDY_SHIFT 0 #define AK8975_REG_ST1_DRDY_MASK (1 << AK8975_REG_ST1_DRDY_SHIFT) #define AK8975_REG_HXL 0x03 #define AK8975_REG_HXH 0x04 #define AK8975_REG_HYL 0x05 #define AK8975_REG_HYH 0x06 #define AK8975_REG_HZL 0x07 #define AK8975_REG_HZH 0x08 #define AK8975_REG_ST2 0x09 #define AK8975_REG_ST2_DERR_SHIFT 2 #define AK8975_REG_ST2_DERR_MASK (1 << AK8975_REG_ST2_DERR_SHIFT) #define AK8975_REG_ST2_HOFL_SHIFT 3 #define AK8975_REG_ST2_HOFL_MASK (1 << AK8975_REG_ST2_HOFL_SHIFT) #define AK8975_REG_CNTL 0x0A #define AK8975_REG_CNTL_MODE_SHIFT 0 #define AK8975_REG_CNTL_MODE_MASK (0xF << AK8975_REG_CNTL_MODE_SHIFT) #define AK8975_REG_CNTL_MODE_POWER_DOWN 0x00 #define AK8975_REG_CNTL_MODE_ONCE 0x01 #define AK8975_REG_CNTL_MODE_SELF_TEST 0x08 #define AK8975_REG_CNTL_MODE_FUSE_ROM 0x0F #define AK8975_REG_RSVC 0x0B #define AK8975_REG_ASTC 0x0C #define AK8975_REG_TS1 0x0D #define AK8975_REG_TS2 0x0E #define AK8975_REG_I2CDIS 0x0F #define AK8975_REG_ASAX 0x10 #define AK8975_REG_ASAY 0x11 #define AK8975_REG_ASAZ 0x12 #define AK8975_MAX_REGS AK8975_REG_ASAZ /* * AK09912 Register definitions */ #define AK09912_REG_WIA1 0x00 #define AK09912_REG_WIA2 0x01 #define AK09912_DEVICE_ID 0x04 #define AK09911_DEVICE_ID 0x05 #define AK09911_REG_INFO1 0x02 #define AK09911_REG_INFO2 0x03 #define AK09912_REG_ST1 0x10 #define AK09912_REG_ST1_DRDY_SHIFT 0 #define AK09912_REG_ST1_DRDY_MASK (1 << AK09912_REG_ST1_DRDY_SHIFT) #define AK09912_REG_HXL 0x11 #define AK09912_REG_HXH 0x12 #define AK09912_REG_HYL 0x13 #define AK09912_REG_HYH 0x14 #define AK09912_REG_HZL 0x15 #define AK09912_REG_HZH 0x16 #define AK09912_REG_TMPS 0x17 #define AK09912_REG_ST2 0x18 #define AK09912_REG_ST2_HOFL_SHIFT 3 #define AK09912_REG_ST2_HOFL_MASK (1 << AK09912_REG_ST2_HOFL_SHIFT) #define AK09912_REG_CNTL1 0x30 #define AK09912_REG_CNTL2 0x31 #define AK09912_REG_CNTL_MODE_POWER_DOWN 0x00 #define AK09912_REG_CNTL_MODE_ONCE 0x01 #define AK09912_REG_CNTL_MODE_SELF_TEST 0x10 #define AK09912_REG_CNTL_MODE_FUSE_ROM 0x1F #define AK09912_REG_CNTL2_MODE_SHIFT 0 #define AK09912_REG_CNTL2_MODE_MASK (0x1F << AK09912_REG_CNTL2_MODE_SHIFT) #define AK09912_REG_CNTL3 0x32 #define AK09912_REG_TS1 0x33 #define AK09912_REG_TS2 0x34 #define AK09912_REG_TS3 0x35 #define AK09912_REG_I2CDIS 0x36 #define AK09912_REG_TS4 0x37 #define AK09912_REG_ASAX 0x60 #define AK09912_REG_ASAY 0x61 #define AK09912_REG_ASAZ 0x62 #define AK09912_MAX_REGS AK09912_REG_ASAZ /* * Miscellaneous values. */ #define AK8975_MAX_CONVERSION_TIMEOUT 500 #define AK8975_CONVERSION_DONE_POLL_TIME 10 #define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000) /* * 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) { return (((long)data + 128) * 3000) / 256; } /* * 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) { return (((long)data + 128) * 6000) / 256; } /* * 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) { return (((long)data + 128) * 1500) / 256; } /* Compatible Asahi Kasei Compass parts */ enum asahi_compass_chipset { AK8975, AK8963, AK09911, AK09912, AK_MAX_TYPE }; enum ak_ctrl_reg_addr { ST1, ST2, CNTL, ASA_BASE, MAX_REGS, REGS_END, }; enum ak_ctrl_reg_mask { ST1_DRDY, ST2_HOFL, ST2_DERR, CNTL_MODE, MASK_END, }; enum ak_ctrl_mode { POWER_DOWN, MODE_ONCE, SELF_TEST, FUSE_ROM, MODE_END, }; struct ak_def { enum asahi_compass_chipset type; long (*raw_to_gauss)(u16 data); u16 range; u8 ctrl_regs[REGS_END]; u8 ctrl_masks[MASK_END]; u8 ctrl_modes[MODE_END]; u8 data_regs[3]; }; static struct ak_def ak_def_array[AK_MAX_TYPE] = { { .type = AK8975, .raw_to_gauss = ak8975_raw_to_gauss, .range = 4096, .ctrl_regs = { AK8975_REG_ST1, AK8975_REG_ST2, AK8975_REG_CNTL, AK8975_REG_ASAX, AK8975_MAX_REGS}, .ctrl_masks = { AK8975_REG_ST1_DRDY_MASK, AK8975_REG_ST2_HOFL_MASK, AK8975_REG_ST2_DERR_MASK, AK8975_REG_CNTL_MODE_MASK}, .ctrl_modes = { AK8975_REG_CNTL_MODE_POWER_DOWN, AK8975_REG_CNTL_MODE_ONCE, AK8975_REG_CNTL_MODE_SELF_TEST, AK8975_REG_CNTL_MODE_FUSE_ROM}, .data_regs = { AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL}, }, { .type = AK8963, .raw_to_gauss = ak8963_09911_raw_to_gauss, .range = 8190, .ctrl_regs = { AK8975_REG_ST1, AK8975_REG_ST2, AK8975_REG_CNTL, AK8975_REG_ASAX, AK8975_MAX_REGS}, .ctrl_masks = { AK8975_REG_ST1_DRDY_MASK, AK8975_REG_ST2_HOFL_MASK, 0, AK8975_REG_CNTL_MODE_MASK}, .ctrl_modes = { AK8975_REG_CNTL_MODE_POWER_DOWN, AK8975_REG_CNTL_MODE_ONCE, AK8975_REG_CNTL_MODE_SELF_TEST, AK8975_REG_CNTL_MODE_FUSE_ROM}, .data_regs = { AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL}, }, { .type = AK09911, .raw_to_gauss = ak8963_09911_raw_to_gauss, .range = 8192, .ctrl_regs = { AK09912_REG_ST1, AK09912_REG_ST2, AK09912_REG_CNTL2, AK09912_REG_ASAX, AK09912_MAX_REGS}, .ctrl_masks = { AK09912_REG_ST1_DRDY_MASK, AK09912_REG_ST2_HOFL_MASK, 0, AK09912_REG_CNTL2_MODE_MASK}, .ctrl_modes = { AK09912_REG_CNTL_MODE_POWER_DOWN, AK09912_REG_CNTL_MODE_ONCE, AK09912_REG_CNTL_MODE_SELF_TEST, AK09912_REG_CNTL_MODE_FUSE_ROM}, .data_regs = { AK09912_REG_HXL, AK09912_REG_HYL, AK09912_REG_HZL}, }, { .type = AK09912, .raw_to_gauss = ak09912_raw_to_gauss, .range = 32752, .ctrl_regs = { AK09912_REG_ST1, AK09912_REG_ST2, AK09912_REG_CNTL2, AK09912_REG_ASAX, AK09912_MAX_REGS}, .ctrl_masks = { AK09912_REG_ST1_DRDY_MASK, AK09912_REG_ST2_HOFL_MASK, 0, AK09912_REG_CNTL2_MODE_MASK}, .ctrl_modes = { AK09912_REG_CNTL_MODE_POWER_DOWN, AK09912_REG_CNTL_MODE_ONCE, AK09912_REG_CNTL_MODE_SELF_TEST, AK09912_REG_CNTL_MODE_FUSE_ROM}, .data_regs = { AK09912_REG_HXL, AK09912_REG_HYL, AK09912_REG_HZL}, } }; /* * Per-instance context data for the device. */ struct ak8975_data { struct i2c_client *client; struct ak_def *def; struct attribute_group attrs; struct mutex lock; u8 asa[3]; long raw_to_gauss[3]; int eoc_gpio; int eoc_irq; wait_queue_head_t data_ready_queue; unsigned long flags; u8 cntl_cache; }; /* * 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) { u8 wia_val[2]; int ret; /* * Signature for each device: * Device | WIA1 | WIA2 * AK09912 | DEVICE_ID | AK09912_DEVICE_ID * AK09911 | DEVICE_ID | AK09911_DEVICE_ID * AK8975 | DEVICE_ID | NA * AK8963 | DEVICE_ID | NA */ ret = i2c_smbus_read_i2c_block_data(client, AK09912_REG_WIA1, 2, wia_val); if (ret < 0) { dev_err(&client->dev, "Error reading WIA\n"); return ret; } if (wia_val[0] != AK8975_DEVICE_ID) return -ENODEV; switch (type) { case AK8975: case AK8963: return 0; case AK09911: if (wia_val[1] == AK09911_DEVICE_ID) return 0; break; case AK09912: if (wia_val[1] == AK09912_DEVICE_ID) return 0; break; default: dev_err(&client->dev, "Type %d unknown\n", type); } return -ENODEV; } /* * Helper function to write to CNTL register. */ static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode) { u8 regval; int ret; regval = (data->cntl_cache & ~data->def->ctrl_masks[CNTL_MODE]) | data->def->ctrl_modes[mode]; ret = i2c_smbus_write_byte_data(data->client, data->def->ctrl_regs[CNTL], regval); if (ret < 0) { return ret; } data->cntl_cache = regval; /* After mode change wait atleast 100us */ usleep_range(100, 500); return 0; } /* * Handle data ready irq */ static irqreturn_t ak8975_irq_handler(int irq, void *data) { struct ak8975_data *ak8975 = data; set_bit(0, &ak8975->flags); wake_up(&ak8975->data_ready_queue); return IRQ_HANDLED; } /* * Install data ready interrupt handler */ static int ak8975_setup_irq(struct ak8975_data *data) { struct i2c_client *client = data->client; int rc; int irq; if (client->irq) irq = client->irq; else irq = gpio_to_irq(data->eoc_gpio); rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler, IRQF_TRIGGER_RISING | IRQF_ONESHOT, dev_name(&client->dev), data); if (rc < 0) { dev_err(&client->dev, "irq %d request failed, (gpio %d): %d\n", irq, data->eoc_gpio, rc); return rc; } init_waitqueue_head(&data->data_ready_queue); clear_bit(0, &data->flags); data->eoc_irq = irq; return rc; } /* * Perform some start-of-day setup, including reading the asa calibration * values and caching them. */ static int ak8975_setup(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); struct ak8975_data *data = iio_priv(indio_dev); int ret; /* Write the fused rom access mode. */ ret = ak8975_set_mode(data, FUSE_ROM); if (ret < 0) { dev_err(&client->dev, "Error in setting fuse access mode\n"); return ret; } /* Get asa data and store in the device data. */ ret = i2c_smbus_read_i2c_block_data(client, data->def->ctrl_regs[ASA_BASE], 3, data->asa); if (ret < 0) { dev_err(&client->dev, "Not able to read asa data\n"); return ret; } /* After reading fuse ROM data set power-down mode */ ret = ak8975_set_mode(data, POWER_DOWN); if (ret < 0) { dev_err(&client->dev, "Error in setting power-down mode\n"); return ret; } if (data->eoc_gpio > 0 || client->irq > 0) { ret = ak8975_setup_irq(data); if (ret < 0) { dev_err(&client->dev, "Error setting data ready interrupt\n"); return ret; } } data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]); data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]); data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]); return 0; } static int wait_conversion_complete_gpio(struct ak8975_data *data) { struct i2c_client *client = data->client; u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT; int ret; /* Wait for the conversion to complete. */ while (timeout_ms) { msleep(AK8975_CONVERSION_DONE_POLL_TIME); if (gpio_get_value(data->eoc_gpio)) break; timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME; } if (!timeout_ms) { dev_err(&client->dev, "Conversion timeout happened\n"); return -EINVAL; } ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]); if (ret < 0) dev_err(&client->dev, "Error in reading ST1\n"); return ret; } static int wait_conversion_complete_polled(struct ak8975_data *data) { struct i2c_client *client = data->client; u8 read_status; u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT; int ret; /* Wait for the conversion to complete. */ while (timeout_ms) { msleep(AK8975_CONVERSION_DONE_POLL_TIME); ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]); if (ret < 0) { dev_err(&client->dev, "Error in reading ST1\n"); return ret; } read_status = ret; if (read_status) break; timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME; } if (!timeout_ms) { dev_err(&client->dev, "Conversion timeout happened\n"); return -EINVAL; } return read_status; } /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */ static int wait_conversion_complete_interrupt(struct ak8975_data *data) { int ret; ret = wait_event_timeout(data->data_ready_queue, test_bit(0, &data->flags), AK8975_DATA_READY_TIMEOUT); clear_bit(0, &data->flags); return ret > 0 ? 0 : -ETIME; } /* * Emits the raw flux value for the x, y, or z axis. */ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) { struct ak8975_data *data = iio_priv(indio_dev); struct i2c_client *client = data->client; int ret; mutex_lock(&data->lock); /* Set up the device for taking a sample. */ ret = ak8975_set_mode(data, MODE_ONCE); if (ret < 0) { dev_err(&client->dev, "Error in setting operating mode\n"); goto exit; } /* Wait for the conversion to complete. */ if (data->eoc_irq) ret = wait_conversion_complete_interrupt(data); else if (gpio_is_valid(data->eoc_gpio)) ret = wait_conversion_complete_gpio(data); else ret = wait_conversion_complete_polled(data); if (ret < 0) goto exit; /* This will be executed only for non-interrupt based waiting case */ if (ret & data->def->ctrl_masks[ST1_DRDY]) { ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST2]); if (ret < 0) { dev_err(&client->dev, "Error in reading ST2\n"); goto exit; } if (ret & (data->def->ctrl_masks[ST2_DERR] | data->def->ctrl_masks[ST2_HOFL])) { dev_err(&client->dev, "ST2 status error 0x%x\n", ret); ret = -EINVAL; goto exit; } } /* Read the flux value from the appropriate register (the register is specified in the iio device attributes). */ ret = i2c_smbus_read_word_data(client, data->def->data_regs[index]); if (ret < 0) { dev_err(&client->dev, "Read axis data fails\n"); goto exit; } mutex_unlock(&data->lock); /* Clamp to valid range. */ *val = clamp_t(s16, ret, -data->def->range, data->def->range); return IIO_VAL_INT; exit: mutex_unlock(&data->lock); return ret; } static int ak8975_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct ak8975_data *data = iio_priv(indio_dev); switch (mask) { case IIO_CHAN_INFO_RAW: return ak8975_read_axis(indio_dev, chan->address, val); case IIO_CHAN_INFO_SCALE: *val = 0; *val2 = data->raw_to_gauss[chan->address]; return IIO_VAL_INT_PLUS_MICRO; } return -EINVAL; } #define AK8975_CHANNEL(axis, index) \ { \ .type = IIO_MAGN, \ .modified = 1, \ .channel2 = IIO_MOD_##axis, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ BIT(IIO_CHAN_INFO_SCALE), \ .address = index, \ } static const struct iio_chan_spec ak8975_channels[] = { AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2), }; static const struct iio_info ak8975_info = { .read_raw = &ak8975_read_raw, .driver_module = THIS_MODULE, }; static const struct acpi_device_id ak_acpi_match[] = { {"AK8975", AK8975}, {"AK8963", AK8963}, {"INVN6500", AK8963}, {"AK09911", AK09911}, {"AK09912", AK09912}, { }, }; MODULE_DEVICE_TABLE(acpi, ak_acpi_match); static const char *ak8975_match_acpi_device(struct device *dev, enum asahi_compass_chipset *chipset) { const struct acpi_device_id *id; id = acpi_match_device(dev->driver->acpi_match_table, dev); if (!id) return NULL; *chipset = (int)id->driver_data; return dev_name(dev); } static int ak8975_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct ak8975_data *data; struct iio_dev *indio_dev; int eoc_gpio; int err; const char *name = NULL; enum asahi_compass_chipset chipset; /* Grab and set up the supplied GPIO. */ if (client->dev.platform_data) eoc_gpio = *(int *)(client->dev.platform_data); else if (client->dev.of_node) eoc_gpio = of_get_gpio(client->dev.of_node, 0); else eoc_gpio = -1; if (eoc_gpio == -EPROBE_DEFER) return -EPROBE_DEFER; /* We may not have a GPIO based IRQ to scan, that is fine, we will poll if so */ if (gpio_is_valid(eoc_gpio)) { err = devm_gpio_request_one(&client->dev, eoc_gpio, GPIOF_IN, "ak_8975"); if (err < 0) { dev_err(&client->dev, "failed to request GPIO %d, error %d\n", eoc_gpio, err); return err; } } /* Register with IIO */ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (indio_dev == NULL) return -ENOMEM; data = iio_priv(indio_dev); i2c_set_clientdata(client, indio_dev); data->client = client; data->eoc_gpio = eoc_gpio; data->eoc_irq = 0; /* id will be NULL when enumerated via ACPI */ if (id) { chipset = (enum asahi_compass_chipset)(id->driver_data); name = id->name; } else if (ACPI_HANDLE(&client->dev)) name = ak8975_match_acpi_device(&client->dev, &chipset); else return -ENOSYS; if (chipset >= AK_MAX_TYPE) { dev_err(&client->dev, "AKM device type unsupported: %d\n", chipset); return -ENODEV; } data->def = &ak_def_array[chipset]; err = ak8975_who_i_am(client, data->def->type); if (err < 0) { dev_err(&client->dev, "Unexpected device\n"); return err; } dev_dbg(&client->dev, "Asahi compass chip %s\n", name); /* Perform some basic start-of-day setup of the device. */ err = ak8975_setup(client); if (err < 0) { dev_err(&client->dev, "%s initialization fails\n", name); return err; } mutex_init(&data->lock); indio_dev->dev.parent = &client->dev; indio_dev->channels = ak8975_channels; indio_dev->num_channels = ARRAY_SIZE(ak8975_channels); indio_dev->info = &ak8975_info; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->name = name; return devm_iio_device_register(&client->dev, indio_dev); } static const struct i2c_device_id ak8975_id[] = { {"ak8975", AK8975}, {"ak8963", AK8963}, {"ak09911", AK09911}, {"ak09912", AK09912}, {} }; MODULE_DEVICE_TABLE(i2c, ak8975_id); static const struct of_device_id ak8975_of_match[] = { { .compatible = "asahi-kasei,ak8975", }, { .compatible = "ak8975", }, { .compatible = "asahi-kasei,ak8963", }, { .compatible = "ak8963", }, { .compatible = "asahi-kasei,ak09911", }, { .compatible = "ak09911", }, { .compatible = "asahi-kasei,ak09912", }, { .compatible = "ak09912", }, {} }; MODULE_DEVICE_TABLE(of, ak8975_of_match); static struct i2c_driver ak8975_driver = { .driver = { .name = "ak8975", .of_match_table = of_match_ptr(ak8975_of_match), .acpi_match_table = ACPI_PTR(ak_acpi_match), }, .probe = ak8975_probe, .id_table = ak8975_id, }; module_i2c_driver(ak8975_driver); MODULE_AUTHOR("Laxman Dewangan "); MODULE_DESCRIPTION("AK8975 magnetometer driver"); MODULE_LICENSE("GPL");