diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/magnetometer/mmc35240.c | 62 |
1 files changed, 58 insertions, 4 deletions
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c index b2ab58e..7a2ea71 100644 --- a/drivers/iio/magnetometer/mmc35240.c +++ b/drivers/iio/magnetometer/mmc35240.c @@ -58,6 +58,31 @@ #define MMC35240_WAIT_CHARGE_PUMP 50000 /* us */ #define MMC53240_WAIT_SET_RESET 1000 /* us */ +/* + * Memsic OTP process code piece is put here for reference: + * + * #define OTP_CONVERT(REG) ((float)((REG) >=32 ? (32 - (REG)) : (REG)) * 0.006 + * 1) For X axis, the COEFFICIENT is always 1. + * 2) For Y axis, the COEFFICIENT is as below: + * f_OTP_matrix[4] = OTP_CONVERT(((reg_data[1] & 0x03) << 4) | + * (reg_data[2] >> 4)) + 1.0; + * 3) For Z axis, the COEFFICIENT is as below: + * f_OTP_matrix[8] = (OTP_CONVERT(reg_data[3] & 0x3f) + 1) * 1.35; + * We implemented the OTP logic into driver. + */ + +/* scale = 1000 here for Y otp */ +#define MMC35240_OTP_CONVERT_Y(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 6) + +/* 0.6 * 1.35 = 0.81, scale 10000 for Z otp */ +#define MMC35240_OTP_CONVERT_Z(REG) (((REG) >= 32 ? (32 - (REG)) : (REG)) * 81) + +#define MMC35240_X_COEFF(x) (x) +#define MMC35240_Y_COEFF(y) (y + 1000) +#define MMC35240_Z_COEFF(z) (z + 13500) + +#define MMC35240_OTP_START_ADDR 0x1B + enum mmc35240_resolution { MMC35240_16_BITS_SLOW = 0, /* 100 Hz */ MMC35240_16_BITS_FAST, /* 200 Hz */ @@ -102,6 +127,10 @@ struct mmc35240_data { struct mutex mutex; struct regmap *regmap; enum mmc35240_resolution res; + + /* OTP compensation */ + int axis_coef[3]; + int axis_scale[3]; }; static const int mmc35240_samp_freq[] = {100, 200, 333, 666}; @@ -172,8 +201,9 @@ static int mmc35240_hw_set(struct mmc35240_data *data, bool set) static int mmc35240_init(struct mmc35240_data *data) { - int ret; + int ret, y_convert, z_convert; unsigned int reg_id; + u8 otp_data[6]; ret = regmap_read(data->regmap, MMC35240_REG_ID, ®_id); if (ret < 0) { @@ -197,9 +227,30 @@ static int mmc35240_init(struct mmc35240_data *data) return ret; /* set default sampling frequency */ - return regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, - MMC35240_CTRL1_BW_MASK, - data->res << MMC35240_CTRL1_BW_SHIFT); + ret = regmap_update_bits(data->regmap, MMC35240_REG_CTRL1, + MMC35240_CTRL1_BW_MASK, + data->res << MMC35240_CTRL1_BW_SHIFT); + if (ret < 0) + return ret; + + ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR, + (u8 *)otp_data, sizeof(otp_data)); + if (ret < 0) + return ret; + + y_convert = MMC35240_OTP_CONVERT_Y(((otp_data[1] & 0x03) << 4) | + (otp_data[2] >> 4)); + z_convert = MMC35240_OTP_CONVERT_Z(otp_data[3] & 0x3f); + + data->axis_coef[0] = MMC35240_X_COEFF(1); + data->axis_coef[1] = MMC35240_Y_COEFF(y_convert); + data->axis_coef[2] = MMC35240_Z_COEFF(z_convert); + + data->axis_scale[0] = 1; + data->axis_scale[1] = 1000; + data->axis_scale[2] = 10000; + + return 0; } static int mmc35240_take_measurement(struct mmc35240_data *data) @@ -286,6 +337,9 @@ static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index, default: return -EINVAL; } + /* apply OTP compensation */ + *val = (*val) * data->axis_coef[index] / data->axis_scale[index]; + return 0; } |
