linux-imx

/*

 * MMC35240 - MEMSIC 3-axis Magnetic Sensor

 *

 * Copyright (c) 2015, Intel Corporation.

 *

 * This file is subject to the terms and conditions of version 2 of

 * the GNU General Public License.  See the file COPYING in the main

 * directory of this archive for more details.

 *

 * IIO driver for MMC35240 (7-bit I2C slave address 0x30).

 *

 * TODO: offset, ACPI, continuous measurement mode, PM

 */

​

#include <linux/module.h>

#include <linux/init.h>

#include <linux/i2c.h>

#include <linux/delay.h>

#include <linux/regmap.h>

#include <linux/acpi.h>

#include <linux/pm.h>

​

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

​

#define MMC35240_DRV_NAME "mmc35240"

#define MMC35240_REGMAP_NAME "mmc35240_regmap"

​

#define MMC35240_REG_XOUT_L 0x00

#define MMC35240_REG_XOUT_H 0x01

#define MMC35240_REG_YOUT_L 0x02

#define MMC35240_REG_YOUT_H 0x03

#define MMC35240_REG_ZOUT_L 0x04

#define MMC35240_REG_ZOUT_H 0x05

​

#define MMC35240_REG_STATUS 0x06

#define MMC35240_REG_CTRL0  0x07

#define MMC35240_REG_CTRL1  0x08

​

#define MMC35240_REG_ID     0x20

​

#define MMC35240_STATUS_MEAS_DONE_BIT   BIT(0)

​

#define MMC35240_CTRL0_REFILL_BIT   BIT(7)

#define MMC35240_CTRL0_RESET_BIT    BIT(6)

#define MMC35240_CTRL0_SET_BIT      BIT(5)

#define MMC35240_CTRL0_CMM_BIT      BIT(1)

#define MMC35240_CTRL0_TM_BIT       BIT(0)

​

/* output resolution bits */

#define MMC35240_CTRL1_BW0_BIT      BIT(0)

#define MMC35240_CTRL1_BW1_BIT      BIT(1)

​

#define MMC35240_CTRL1_BW_MASK   (MMC35240_CTRL1_BW0_BIT | \

         MMC35240_CTRL1_BW1_BIT)

#define MMC35240_CTRL1_BW_SHIFT     0

​

#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, /* 7.92 ms */

    MMC35240_16_BITS_FAST,     /* 4.08 ms */

    MMC35240_14_BITS,          /* 2.16 ms */

    MMC35240_12_BITS,          /* 1.20 ms */

};

​