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/*
* procfs1.c - create a "file" in /proc
*
*/
#include <linux/module.h> /* Specifically, a module */
#include <linux/kernel.h> /* We're doing kernel work */
#include <linux/proc_fs.h> /* Necessary because we use the proc fs */
#include <linux/gpio.h>
#include <mach/wmt_iomux.h>
#include <asm/uaccess.h> //for copy_from_user
#include <linux/delay.h> // for mdelay
#define DRIVER_AUTHOR "rubbitxiao "
#define DRIVER_DESC "printer power control"
#define procfs_name "gpio_ctrl"
extern int wmt_getsyspara(char *varname, unsigned char *varval, int *varlen);
extern struct proc_dir_entry proc_root;
/**
* This structure hold information about the /proc file
*
*/
static struct proc_dir_entry *Our_Proc_File;
int power_on = -1; //control printer power on/off
int lid_stat = -1; //inflext printer lid open or close status
enum{
LOW=0,
HIGH,
};
/* Put data into the proc fs file.
*
* Arguments
* =========
* 1. The buffer where the data is to be inserted, if
* you decide to use it.
* 2. A pointer to a pointer to characters. This is
* useful if you don't want to use the buffer
* allocated by the kernel.
* 3. The current position in the file
* 4. The size of the buffer in the first argument.
* 5. Write a "1" here to indicate EOF.
* 6. A pointer to data (useful in case one common
* read for multiple /proc/... entries)
*
* Usage and Return Value
* ======================
* A return value of zero means you have no further
* information at this time (end of file). A negative
* return value is an error condition.
*
* For More Information
* ====================
* The way I discovered what to do with this function
* wasn't by reading documentation, but by reading the
* code which used it. I just looked to see what uses
* the get_info field of proc_dir_entry struct (I used a
* combination of find and grep, if you're interested),
* and I saw that it is used in <kernel source
* directory>/fs/proc/array.c.
*
* If something is unknown about the kernel, this is
* usually the way to go. In Linux we have the great
* advantage of having the kernel source code for
* free - use it.
*/
static int
procfile_read(char *buffer,
char **buffer_location,
off_t offset, int buffer_length, int *eof, void *data)
{
int ret;
int value = -1;
if (offset > 0) {
/* we have finished to read, return 0 */
ret = 0;
} else {
if(lid_stat >=0){
gpio_direction_input(lid_stat);
value = __gpio_get_value(lid_stat);
/* fill the buffer, return the buffer size */
ret = sprintf(buffer,"%d",value);
}else{
printk("err! have not set wmt.gpo.printer uboot variant\n");
ret = -1;
}
}
return ret;
}
static int procfile_write(struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
int ret = 0;
char tmp[128];
int num;
int on = 0;
if(buffer && !copy_from_user(tmp, buffer, sizeof(tmp))) {
num = sscanf(tmp, "%d", &on);
printk("your input power on/off:%d\n",on);
if(power_on<0){
printk("err! have not set wmt.gpo.printer uboot variant\n");
return -1;
}
if(on){
gpio_direction_output(power_on, HIGH);
mdelay(200);
printk("power on printer\n");
}else{
gpio_direction_output(power_on, LOW);
printk("power off printer\n");
}
return strlen(tmp);
}else{
printk("copy_from_user failed or buffer is null\n");
return -1;
}
}
static int __init wifi_proc_init(void)
{
int retval = 0;
int varlen = 127;
char buf[200]={0};
Our_Proc_File = create_proc_entry(procfs_name, 0644, NULL);
if (Our_Proc_File == NULL) {
remove_proc_entry(procfs_name, NULL);
printk(KERN_ALERT "Error: Could not initialize /proc/%s\n",
procfs_name);
return -ENOMEM;
}
/*
* wmt.gpo.printer format as follows:
* power_on:lid_stat
* for example: setenv wmt.gpo.printer 153:3
* gpio8 for power on; gpio9 for lid status
*/
retval = wmt_getsyspara("wmt.gpo.printer", buf, &varlen);
if(!retval)
{
sscanf(buf, "%d:%d",&power_on,&lid_stat);
printk("power_on:%d,lid_stat:%d\n", power_on,lid_stat);
//request gpio for printer power control
retval = gpio_request(power_on, "printer power pin");
if(retval < 0) {
printk("reques gpio:%x failed!!! for printer power pin\n",power_on);
return -1;
}else{
printk("request gpio:%d for printer power pin success!!!\n", power_on);
}
//request gpio for printer lid status
retval = gpio_request(lid_stat, "printer lid status");
if(retval < 0) {
printk("reques gpio:%x failed!!! for printer lid status\n",lid_stat);
return -1;
}else{
printk("request gpio:%d for printer lid status success!!!\n", lid_stat);
}
}else{
printk("have not set wmt.gpo.printer");
}
Our_Proc_File->read_proc = procfile_read;
Our_Proc_File->write_proc = procfile_write;
Our_Proc_File->mode = S_IFREG | S_IRUGO;
Our_Proc_File->uid = 0;
Our_Proc_File->gid = 0;
Our_Proc_File->size = 37;
return 0; /* everything is ok */
}
static void __exit wifi_proc_uninit(void)
{
remove_proc_entry(procfs_name, NULL);
if(power_on)
gpio_free(power_on);
if(lid_stat)
gpio_free(lid_stat);
}
module_init(wifi_proc_init);
module_exit(wifi_proc_uninit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");
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