[PATCH] chardev: GPIO for SCx200 & PC-8736x: add 'v' command to device-file

Add a new driver command: 'v' which calls gpio_dump() on the pin.  The output
goes to the log, like all other INFO messages in the original driver.  Giving
the user control over the feedback they 'need' is construed to be a
user-friendly feature, and allows us (later) to dial down many INFO messages
to DEBUG log-level.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 17 insertions, 2 deletions

diff --git a/arch/i386/kernel/scx200.c b/arch/i386/kernel/scx200.c
index 9e96a785dd05..009e6aa16f73 100644
--- a/arch/i386/kernel/scx200.c
+++ b/arch/i386/kernel/scx200.c
@@ -105,7 +105,6 @@ u32 scx200_gpio_configure(unsigned index, u32 mask, u32 bits)
         return config;
 }
 
-#if 0
 void scx200_gpio_dump(unsigned index)
 {
         u32 config = scx200_gpio_configure(index, ~0, 0);
@@ -120,7 +119,6 @@ void scx200_gpio_dump(unsigned index)
                (config & 32) ? "HI"     : "LO",         /* trigger on rising/falling edge */
                (config & 64) ? "DEBOUNCE" : "");        /* debounce */
 }
-#endif  /*  0  */
 
 static int __init scx200_init(void)
 {
@@ -141,4 +139,5 @@ module_exit(scx200_cleanup);
 EXPORT_SYMBOL(scx200_gpio_base);
 EXPORT_SYMBOL(scx200_gpio_shadow);
 EXPORT_SYMBOL(scx200_gpio_configure);
+EXPORT_SYMBOL(scx200_gpio_dump);
 EXPORT_SYMBOL(scx200_cb_base);
diff --git a/drivers/char/scx200_gpio.c b/drivers/char/scx200_gpio.c
index e6e52c48697b..a1a56c5c8a84 100644
--- a/drivers/char/scx200_gpio.c
+++ b/drivers/char/scx200_gpio.c
@@ -41,6 +41,7 @@ static ssize_t scx200_gpio_write(struct file *file, const char __user *data,
 {
         unsigned m = iminor(file->f_dentry->d_inode);
         size_t i;
+        int err = 0;
 
         for (i = 0; i < len; ++i) {
                 char c;
@@ -77,8 +78,23 @@ static ssize_t scx200_gpio_write(struct file *file, const char __user *data,
                         printk(KERN_INFO NAME ": GPIO%d pull up disabled\n", m);
                         scx200_gpio_configure(m, ~4, 0);
                         break;
+
+                case 'v':
+                        /* View Current pin settings */
+                        scx200_gpio_dump(m);
+                        break;
+                case '\n':
+                        /* end of settings string, do nothing */
+                        break;
+                default:
+                        printk(KERN_ERR NAME
+                               ": GPIO-%2d bad setting: chr<0x%2x>\n", m,
+                               (int)c);
+                        err++;
                 }
         }
+        if (err)
+                return -EINVAL; /* full string handled, report error */
 
         return len;
 }