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Commit e0c70b80 authored by Paul Thomas's avatar Paul Thomas Committed by Linus Torvalds
Browse files

hwmon: add TI ads7871 a/d converter driver 



[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarPaul Thomas <pthomas8589@gmail.com>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4a70a413

drivers/hwmon/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -802,6 +802,15 @@ config SENSORS_ADS7828 
	  This driver can also be built as a module.  If so, the module

	  will be called ads7828.



config SENSORS_ADS7871

	tristate "Texas Instruments ADS7871 A/D converter"

	depends on SPI

	help

	  If you say yes here you get support for TI ADS7871 & ADS7870



	  This driver can also be built as a module.  If so, the module

	  will be called ads7871.



config SENSORS_AMC6821

	tristate "Texas Instruments AMC6821"

	depends on I2C  && EXPERIMENTAL

drivers/hwmon/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ obj-$(CONFIG_SENSORS_ADM1029) += adm1029.o 
obj-$(CONFIG_SENSORS_ADM1031)	+= adm1031.o

obj-$(CONFIG_SENSORS_ADM9240)	+= adm9240.o

obj-$(CONFIG_SENSORS_ADS7828)	+= ads7828.o

obj-$(CONFIG_SENSORS_ADS7871)	+= ads7871.o

obj-$(CONFIG_SENSORS_ADT7411)	+= adt7411.o

obj-$(CONFIG_SENSORS_ADT7462)	+= adt7462.o

obj-$(CONFIG_SENSORS_ADT7470)	+= adt7470.o

drivers/hwmon/ads7871.c

0 → 100644
+253 −0
Original line number Diff line number Diff line 
/*

 *  ads7871 - driver for TI ADS7871 A/D converter

 *

 *  Copyright (c) 2010 Paul Thomas <pthomas8589@gmail.com>

 *

 *  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.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License version 2 or

 *  later as publishhed by the Free Software Foundation.

 *

 *	You need to have something like this in struct spi_board_info

 *	{

 *		.modalias	= "ads7871",

 *		.max_speed_hz	= 2*1000*1000,

 *		.chip_select	= 0,

 *		.bus_num	= 1,

 *	},

 */



/*From figure 18 in the datasheet*/

/*Register addresses*/

#define REG_LS_BYTE	0 /*A/D Output Data, LS Byte*/

#define REG_MS_BYTE	1 /*A/D Output Data, MS Byte*/

#define REG_PGA_VALID	2 /*PGA Valid Register*/

#define REG_AD_CONTROL	3 /*A/D Control Register*/

#define REG_GAIN_MUX	4 /*Gain/Mux Register*/

#define REG_IO_STATE	5 /*Digital I/O State Register*/

#define REG_IO_CONTROL	6 /*Digital I/O Control Register*/

#define REG_OSC_CONTROL	7 /*Rev/Oscillator Control Register*/

#define REG_SER_CONTROL 24 /*Serial Interface Control Register*/

#define REG_ID		31 /*ID Register*/



/*From figure 17 in the datasheet

* These bits get ORed with the address to form

* the instruction byte */

/*Instruction Bit masks*/

#define INST_MODE_bm	(1<<7)

#define INST_READ_bm	(1<<6)

#define INST_16BIT_bm	(1<<5)



/*From figure 18 in the datasheet*/

/*bit masks for Rev/Oscillator Control Register*/

#define MUX_CNV_bv	7

#define MUX_CNV_bm	(1<<MUX_CNV_bv)

#define MUX_M3_bm	(1<<3) /*M3 selects single ended*/

#define MUX_G_bv	4 /*allows for reg = (gain << MUX_G_bv) | ...*/



/*From figure 18 in the datasheet*/

/*bit masks for Rev/Oscillator Control Register*/

#define OSC_OSCR_bm	(1<<5)

#define OSC_OSCE_bm	(1<<4)

#define OSC_REFE_bm	(1<<3)

#define OSC_BUFE_bm	(1<<2)

#define OSC_R2V_bm	(1<<1)

#define OSC_RBG_bm	(1<<0)



#include <linux/module.h>

#include <linux/init.h>

#include <linux/spi/spi.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/err.h>

#include <linux/mutex.h>

#include <linux/delay.h>



#define DEVICE_NAME	"ads7871"



struct ads7871_data {

	struct device	*hwmon_dev;

	struct mutex	update_lock;

};



static int ads7871_read_reg8(struct spi_device *spi, int reg)

{

	int ret;

	reg = reg | INST_READ_bm;

	ret = spi_w8r8(spi, reg);

	return ret;

}



static int ads7871_read_reg16(struct spi_device *spi, int reg)

{

	int ret;

	reg = reg | INST_READ_bm | INST_16BIT_bm;

	ret = spi_w8r16(spi, reg);

	return ret;

}



static int ads7871_write_reg8(struct spi_device *spi, int reg, u8 val)

{

	u8 tmp[2] = {reg, val};

	return spi_write(spi, tmp, sizeof(tmp));

}



static ssize_t show_voltage(struct device *dev,

		struct device_attribute *da, char *buf)

{

	struct spi_device *spi = to_spi_device(dev);

	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

	int ret, val, i = 0;

	uint8_t channel, mux_cnv;



	channel = attr->index;

	/*TODO: add support for conversions

	 *other than single ended with a gain of 1*/

	/*MUX_M3_bm forces single ended*/

	/*This is also where the gain of the PGA would be set*/

	ads7871_write_reg8(spi, REG_GAIN_MUX,

		(MUX_CNV_bm | MUX_M3_bm | channel));



	ret = ads7871_read_reg8(spi, REG_GAIN_MUX);

	mux_cnv = ((ret & MUX_CNV_bm)>>MUX_CNV_bv);

	/*on 400MHz arm9 platform the conversion

	 *is already done when we do this test*/

	while ((i < 2) && mux_cnv) {

		i++;

		ret = ads7871_read_reg8(spi, REG_GAIN_MUX);

		mux_cnv = ((ret & MUX_CNV_bm)>>MUX_CNV_bv);

		msleep_interruptible(1);

	}



	if (mux_cnv == 0) {

		val = ads7871_read_reg16(spi, REG_LS_BYTE);

		/*result in volts*10000 = (val/8192)*2.5*10000*/

		val = ((val>>2) * 25000) / 8192;

		return sprintf(buf, "%d\n", val);

	} else {

		return -1;

	}

}



static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, show_voltage, NULL, 0);

static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, show_voltage, NULL, 1);

static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, show_voltage, NULL, 2);

static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, show_voltage, NULL, 3);

static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, show_voltage, NULL, 4);

static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, show_voltage, NULL, 5);

static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, show_voltage, NULL, 6);

static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, show_voltage, NULL, 7);



static struct attribute *ads7871_attributes[] = {

	&sensor_dev_attr_in0_input.dev_attr.attr,

	&sensor_dev_attr_in1_input.dev_attr.attr,

	&sensor_dev_attr_in2_input.dev_attr.attr,

	&sensor_dev_attr_in3_input.dev_attr.attr,

	&sensor_dev_attr_in4_input.dev_attr.attr,

	&sensor_dev_attr_in5_input.dev_attr.attr,

	&sensor_dev_attr_in6_input.dev_attr.attr,

	&sensor_dev_attr_in7_input.dev_attr.attr,

	NULL

};



static const struct attribute_group ads7871_group = {

	.attrs = ads7871_attributes,

};



static int __devinit ads7871_probe(struct spi_device *spi)

{

	int status, ret, err = 0;

	uint8_t val;

	struct ads7871_data *pdata;



	dev_dbg(&spi->dev, "probe\n");



	pdata = kzalloc(sizeof(struct ads7871_data), GFP_KERNEL);

	if (!pdata) {

		err = -ENOMEM;

		goto exit;

	}



	status = sysfs_create_group(&spi->dev.kobj, &ads7871_group);

	if (status < 0)

		goto error_free;



	pdata->hwmon_dev = hwmon_device_register(&spi->dev);

	if (IS_ERR(pdata->hwmon_dev)) {

		err = PTR_ERR(pdata->hwmon_dev);

		goto error_remove;

	}



	spi_set_drvdata(spi, pdata);



	/* Configure the SPI bus */

	spi->mode = (SPI_MODE_0);

	spi->bits_per_word = 8;

	spi_setup(spi);



	ads7871_write_reg8(spi, REG_SER_CONTROL, 0);

	ads7871_write_reg8(spi, REG_AD_CONTROL, 0);



	val = (OSC_OSCR_bm | OSC_OSCE_bm | OSC_REFE_bm | OSC_BUFE_bm);

	ads7871_write_reg8(spi, REG_OSC_CONTROL, val);

	ret = ads7871_read_reg8(spi, REG_OSC_CONTROL);



	dev_dbg(&spi->dev, "REG_OSC_CONTROL write:%x, read:%x\n", val, ret);

	/*because there is no other error checking on an SPI bus

	we need to make sure we really have a chip*/

	if (val != ret) {

		err = -ENODEV;

		goto error_remove;

	}



	return 0;



error_remove:

	sysfs_remove_group(&spi->dev.kobj, &ads7871_group);

error_free:

	kfree(pdata);

exit:

	return err;

}



static int __devexit ads7871_remove(struct spi_device *spi)

{

	struct ads7871_data *pdata = spi_get_drvdata(spi);



	hwmon_device_unregister(pdata->hwmon_dev);

	sysfs_remove_group(&spi->dev.kobj, &ads7871_group);

	kfree(pdata);

	return 0;

}



static struct spi_driver ads7871_driver = {

	.driver = {

		.name = DEVICE_NAME,

		.bus = &spi_bus_type,

		.owner = THIS_MODULE,

	},



	.probe = ads7871_probe,

	.remove = __devexit_p(ads7871_remove),

};



static int __init ads7871_init(void)

{

	return spi_register_driver(&ads7871_driver);

}



static void __exit ads7871_exit(void)

{

	spi_unregister_driver(&ads7871_driver);

}



module_init(ads7871_init);

module_exit(ads7871_exit);



MODULE_AUTHOR("Paul Thomas <pthomas8589@gmail.com>");

MODULE_DESCRIPTION("TI ADS7871 A/D driver");

MODULE_LICENSE("GPL");