linux-imx

/* display7seg.c - Driver implementation for the 7-segment display

 *                 present on Sun Microsystems CP1400 and CP1500

 *

 * Copyright (c) 2000 Eric Brower (ebrower@usa.net)

 */

​

#include <linux/device.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/fs.h>

#include <linux/errno.h>

#include <linux/major.h>

#include <linux/miscdevice.h>

#include <linux/ioport.h>       /* request_region */

#include <linux/slab.h>

#include <linux/mutex.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/atomic.h>

#include <linux/uaccess.h>      /* put_/get_user            */

#include <asm/io.h>

​

#include <asm/display7seg.h>

​

#define DRIVER_NAME "d7s"

#define PFX     DRIVER_NAME ": "

​

static DEFINE_MUTEX(d7s_mutex);

static int sol_compat = 0;      /* Solaris compatibility mode   */

​

/* Solaris compatibility flag -

 * The Solaris implementation omits support for several

 * documented driver features (ref Sun doc 806-0180-03).  

 * By default, this module supports the documented driver 

 * abilities, rather than the Solaris implementation:

 *

 *  1) Device ALWAYS reverts to OBP-specified FLIPPED mode

 *     upon closure of device or module unload.

 *  2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of

 *     FLIP bit

 *

 * If you wish the device to operate as under Solaris,

 * omitting above features, set this parameter to non-zero.

 */

module_param(sol_compat, int, 0);

MODULE_PARM_DESC(sol_compat, 

         "Disables documented functionality omitted from Solaris driver");

​

MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");

MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500");

MODULE_LICENSE("GPL");

MODULE_SUPPORTED_DEVICE("d7s");

​

struct d7s {

    void __iomem    *regs;

    bool        flipped;

};

struct d7s *d7s_device;

​

/*

 * Register block address- see header for details

 * -----------------------------------------

 * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |

 * -----------------------------------------

 *

 * DP       - Toggles decimal point on/off 

 * ALARM    - Toggles "Alarm" LED green/red

 * FLIP     - Inverts display for upside-down mounted board

 * bits 0-4 - 7-segment display contents

 */

static atomic_t d7s_users = ATOMIC_INIT(0);

​

static int d7s_open(struct inode *inode, struct file *f)

{

    if (D7S_MINOR != iminor(inode))

        return -ENODEV;

    atomic_inc(&d7s_users);

    return 0;

}

​

static int d7s_release(struct inode *inode, struct file *f)

{

    /* Reset flipped state to OBP default only if

     * no other users have the device open and we

     * are not operating in solaris-compat mode

     */

    if (atomic_dec_and_test(&d7s_users) && !sol_compat) {

        struct d7s *p = d7s_device;

        u8 regval = 0;

​

        regval = readb(p->regs);

        if (p->flipped)