linux-imx

/*

 * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles

 * (C) 2007 EADS Astrium

 *

 * This driver is based on the lm75 and other lm_sensors/hwmon drivers

 *

 * Written by Steve Hardy <shardy@redhat.com>

 *

 * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>

 *

 * For further information, see the Documentation/hwmon/ads7828 file.

 *

 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

​

#include <linux/err.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/i2c.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/of_device.h>

#include <linux/platform_data/ads7828.h>

#include <linux/regmap.h>

#include <linux/slab.h>

#include <linux/regulator/consumer.h>

​

/* The ADS7828 registers */

#define ADS7828_CMD_SD_SE   0x80    /* Single ended inputs */

#define ADS7828_CMD_PD1     0x04    /* Internal vref OFF && A/D ON */

#define ADS7828_CMD_PD3     0x0C    /* Internal vref ON && A/D ON */

#define ADS7828_INT_VREF_MV 2500    /* Internal vref is 2.5V, 2500mV */

#define ADS7828_EXT_VREF_MV_MIN 50  /* External vref min value 0.05V */

#define ADS7828_EXT_VREF_MV_MAX 5250    /* External vref max value 5.25V */

​

/* List of supported devices */

enum ads7828_chips { ads7828, ads7830 };

​

/* Client specific data */

struct ads7828_data {

    struct regmap *regmap;

    u8 cmd_byte;            /* Command byte without channel bits */

    unsigned int lsb_resol;     /* Resolution of the ADC sample LSB */

};

​

/* Command byte C2,C1,C0 - see datasheet */

static inline u8 ads7828_cmd_byte(u8 cmd, int ch)

{

    return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);

}

​