[PATCH #3355] Add sysfs support for powering down the OLPC 88W8838 wireless chip.

[Chris Ball]

Hi Deepak,

   > I think the preffered way to do this is via sscanf() of the
   > incoming buffer as you can catch errors such as non-integer
   > input. simple_stroul() will just return 0 which is not what we
   > want.

   > I'd also change the mode to 0400 as this is a write-only bit.

   > My preffered option is to make it r/w, call it wlan_enabled and
   > than we could check the state via the file too by storing the
   > current setting.

All applied in the replacement patch below.  Thanks!

- Chris.

From: Chris Ball <cjb at laptop.org>
Date: Fri, 13 Jun 2008 19:53:30 -0400
Subject: [PATCH #3355] Add sysfs support for powering down the OLPC 88W8838 wireless chip.

This uses the OLPC EC 0x35/0x25 interface.

Signed-off-by: Chris Ball <cjb at laptop.org>
---
 arch/x86/kernel/olpc-pm.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/olpc-pm.c b/arch/x86/kernel/olpc-pm.c
index e99a464..bc6c160 100644
--- a/arch/x86/kernel/olpc-pm.c
+++ b/arch/x86/kernel/olpc-pm.c
@@ -43,6 +43,8 @@
 /* These, and the battery EC commands, should be in an olpc.h. */
 #define EC_WRITE_SCI_MASK 0x1b
 #define EC_READ_SCI_MASK  0x1c
+#define EC_WLAN_ENTER_RESET 0x35
+#define EC_WLAN_LEAVE_RESET 0x25
 
 extern void do_olpc_suspend_lowlevel(void);
 
@@ -69,6 +71,8 @@ static u16 olpc_wakeup_mask = 0;
 static unsigned int test_timeout = 0;
 static char *wackup_source = "none";
 
+static unsigned int wlan_enabled = 1;
+
 struct platform_device olpc_powerbutton_dev = {
 	.name = "powerbutton",
 	.id = -1,
@@ -661,6 +665,30 @@ static ssize_t wackup_show(struct kobject *s, struct kobj_attribute *attr,
 	return sprintf(buf, "%s\n", wackup_source ? wackup_source : "none");
 }
 
+static ssize_t wlan_enabled_show(struct kobject *s, struct kobj_attribute *attr,
+		char *buf)
+{
+	return sprintf(buf, "%u\n", wlan_enabled);
+}
+
+static ssize_t wlan_enabled_store(struct kobject *s, struct kobj_attribute *attr,
+		const char *buf, size_t n)
+{
+	unsigned int val;
+	if (!sscanf(buf, "%u", &val) == 1) {
+		return -EINVAL;
+	}
+	if (val == 1) {
+		olpc_ec_cmd(EC_WLAN_LEAVE_RESET, NULL, 0, NULL, 0);
+		wlan_enabled = 1;
+	}
+	else if (val == 0) {
+		olpc_ec_cmd(EC_WLAN_ENTER_RESET, NULL, 0, NULL, 0);
+		wlan_enabled = 0;
+	}
+	return n;
+}
+
 static struct kobj_attribute control_attr =
 	__ATTR(olpc-pm, 0644, control_show, control_store);
 
@@ -670,10 +698,14 @@ static struct kobj_attribute test_attr =
 static struct kobj_attribute wackup_attr =
 	__ATTR(wakeup-source, 0400, wackup_show, NULL);
 
+static struct kobj_attribute wlanenabled_attr =
+	__ATTR(wlan-enabled, 0644, wlan_enabled_show, wlan_enabled_store);
+
 static struct attribute * olpc_attributes[] = {
 	&control_attr.attr,
 	&test_attr.attr,
 	&wackup_attr.attr,
+	&wlanenabled_attr.attr,
 	NULL
 };
 
-- 
1.5.4.3