diff options
-rw-r--r-- | drivers/iio/magnetometer/ak8975.c | 281 |
1 files changed, 186 insertions, 95 deletions
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c index 4e69480e67b5..0f86a8e72034 100644 --- a/drivers/iio/magnetometer/ak8975.c +++ b/drivers/iio/magnetometer/ak8975.c @@ -86,13 +86,155 @@ #define AK8975_MAX_CONVERSION_TIMEOUT 500 #define AK8975_CONVERSION_DONE_POLL_TIME 10 #define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000) -#define RAW_TO_GAUSS_8975(asa) ((((asa) + 128) * 3000) / 256) -#define RAW_TO_GAUSS_8963(asa) ((((asa) + 128) * 6000) / 256) + +/* + * 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, 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_raw_to_gauss(u16 data) +{ + return (((long)data + 128) * 6000) / 256; +} /* Compatible Asahi Kasei Compass parts */ enum asahi_compass_chipset { AK8975, AK8963, + 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_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}, + }, }; /* @@ -100,40 +242,36 @@ enum asahi_compass_chipset { */ 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]; - u8 reg_cache[AK8975_MAX_REGS]; int eoc_gpio; int eoc_irq; wait_queue_head_t data_ready_queue; unsigned long flags; - enum asahi_compass_chipset chipset; -}; - -static const int ak8975_index_to_reg[] = { - AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL, + u8 cntl_cache; }; /* - * Helper function to write to the I2C device's registers. + * Helper function to write to CNTL register. */ -static int ak8975_write_data(struct i2c_client *client, - u8 reg, u8 val, u8 mask, u8 shift) +static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode) { - struct iio_dev *indio_dev = i2c_get_clientdata(client); - struct ak8975_data *data = iio_priv(indio_dev); u8 regval; int ret; - regval = (data->reg_cache[reg] & ~mask) | (val << shift); - ret = i2c_smbus_write_byte_data(client, reg, regval); + 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) { - dev_err(&client->dev, "Write to device fails status %x\n", ret); return ret; } - data->reg_cache[reg] = regval; + data->cntl_cache = regval; + /* After mode change wait atleast 100us */ + usleep_range(100, 500); return 0; } @@ -207,18 +345,15 @@ static int ak8975_setup(struct i2c_client *client) } /* Write the fused rom access mode. */ - ret = ak8975_write_data(client, - AK8975_REG_CNTL, - AK8975_REG_CNTL_MODE_FUSE_ROM, - AK8975_REG_CNTL_MODE_MASK, - AK8975_REG_CNTL_MODE_SHIFT); + 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, AK8975_REG_ASAX, + 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"); @@ -226,11 +361,7 @@ static int ak8975_setup(struct i2c_client *client) } /* After reading fuse ROM data set power-down mode */ - ret = ak8975_write_data(client, - AK8975_REG_CNTL, - AK8975_REG_CNTL_MODE_POWER_DOWN, - AK8975_REG_CNTL_MODE_MASK, - AK8975_REG_CNTL_MODE_SHIFT); + ret = ak8975_set_mode(data, POWER_DOWN); if (ret < 0) { dev_err(&client->dev, "Error in setting power-down mode\n"); return ret; @@ -245,56 +376,9 @@ static int ak8975_setup(struct i2c_client *client) } } -/* - * 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(). - */ - if (data->chipset == AK8963) { - /* - * H range is +-8190 and magnetometer range is +-4912. - * So HuT using the above explanation for 8975, - * 4912/8190 = ~ 6/10. - * So the Hadj should use 6/10 instead of 3/10. - */ - data->raw_to_gauss[0] = RAW_TO_GAUSS_8963(data->asa[0]); - data->raw_to_gauss[1] = RAW_TO_GAUSS_8963(data->asa[1]); - data->raw_to_gauss[2] = RAW_TO_GAUSS_8963(data->asa[2]); - } else { - data->raw_to_gauss[0] = RAW_TO_GAUSS_8975(data->asa[0]); - data->raw_to_gauss[1] = RAW_TO_GAUSS_8975(data->asa[1]); - data->raw_to_gauss[2] = RAW_TO_GAUSS_8975(data->asa[2]); - } + 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; } @@ -317,7 +401,7 @@ static int wait_conversion_complete_gpio(struct ak8975_data *data) return -EINVAL; } - ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1); + ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]); if (ret < 0) dev_err(&client->dev, "Error in reading ST1\n"); @@ -334,7 +418,8 @@ static int wait_conversion_complete_polled(struct ak8975_data *data) /* Wait for the conversion to complete. */ while (timeout_ms) { msleep(AK8975_CONVERSION_DONE_POLL_TIME); - ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1); + 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; @@ -377,11 +462,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) mutex_lock(&data->lock); /* Set up the device for taking a sample. */ - ret = ak8975_write_data(client, - AK8975_REG_CNTL, - AK8975_REG_CNTL_MODE_ONCE, - AK8975_REG_CNTL_MODE_MASK, - AK8975_REG_CNTL_MODE_SHIFT); + ret = ak8975_set_mode(data, MODE_ONCE); if (ret < 0) { dev_err(&client->dev, "Error in setting operating mode\n"); goto exit; @@ -398,14 +479,15 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) goto exit; /* This will be executed only for non-interrupt based waiting case */ - if (ret & AK8975_REG_ST1_DRDY_MASK) { - ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2); + 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 & (AK8975_REG_ST2_DERR_MASK | - AK8975_REG_ST2_HOFL_MASK)) { + 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; @@ -414,7 +496,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) /* Read the flux value from the appropriate register (the register is specified in the iio device attributes). */ - ret = i2c_smbus_read_word_data(client, ak8975_index_to_reg[index]); + 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; @@ -423,7 +505,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) mutex_unlock(&data->lock); /* Clamp to valid range. */ - *val = clamp_t(s16, ret, -4096, 4095); + *val = clamp_t(s16, ret, -data->def->range, data->def->range); return IIO_VAL_INT; exit: @@ -497,6 +579,7 @@ static int ak8975_probe(struct i2c_client *client, 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) @@ -536,14 +619,20 @@ static int ak8975_probe(struct i2c_client *client, /* id will be NULL when enumerated via ACPI */ if (id) { - data->chipset = - (enum asahi_compass_chipset)(id->driver_data); + chipset = (enum asahi_compass_chipset)(id->driver_data); name = id->name; } else if (ACPI_HANDLE(&client->dev)) - name = ak8975_match_acpi_device(&client->dev, &data->chipset); + 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]; dev_dbg(&client->dev, "Asahi compass chip %s\n", name); /* Perform some basic start-of-day setup of the device. */ @@ -574,7 +663,9 @@ 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", }, + {} }; MODULE_DEVICE_TABLE(of, ak8975_of_match); |