linux-imx

/*

 * MC33880 high-side/low-side switch GPIO driver

 * Copyright (c) 2009 Intel Corporation

 *

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

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

 * published by the Free Software Foundation.

 *

 * 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.

 */

​

/* Supports:

 * Freescale MC33880 high-side/low-side switch

 */

​

#include <linux/init.h>

#include <linux/mutex.h>

#include <linux/spi/spi.h>

#include <linux/spi/mc33880.h>

#include <linux/gpio/driver.h>

#include <linux/slab.h>

#include <linux/module.h>

​

#define DRIVER_NAME "mc33880"

​

/*

 * Pin configurations, see MAX7301 datasheet page 6

 */

#define PIN_CONFIG_MASK 0x03

#define PIN_CONFIG_IN_PULLUP 0x03

#define PIN_CONFIG_IN_WO_PULLUP 0x02

#define PIN_CONFIG_OUT 0x01

​

#define PIN_NUMBER 8

​

​

/*

 * Some registers must be read back to modify.

 * To save time we cache them here in memory

 */

struct mc33880 {

    struct mutex    lock;   /* protect from simultaneous accesses */

    u8      port_config;

    struct gpio_chip chip;

    struct spi_device *spi;

};

​

static int mc33880_write_config(struct mc33880 *mc)

{

    return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));

}

​

​

static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)

{

    if (value)