panasonic-laptop.c: add support for CD power management

Hello,

attached is a patch to the panasonic-laptop driver to enable power management (i.e. on/off) of the built-in optical drive. It creates a sysfs interface /sys/devices/platform/panasonic/cdpower which can be either queried or written to. Writing "0" enables the device, "1" disables it.

This code is based on reading the existing code[1][2], examining the DSDT on my CF-W4 system and experimentation.

The presence of the CF-Y series in the DMI table is based on the assumption that this method works on recent CF-Yx models.

I have a few questions I'd like to clear up before actually submitting this for inclusion:

1) Is a platform device the right way to do this?

2) Rather than checking the DMI system vendor and product name would it be a better approach to simply check for the presence of the \_SB.FBAY() and \_SB.STAT() ACPI methods and enable the platform device on any (Panasonic) system where these are present? This would seem like a more future-proof approach.

3) Please advise on the correct way to propagate an error result from the functions that call the ACPI methods {get,set}optd_power_state() to userspace in the sysfs interface. I couldn't find a straightforward example anywhere.

Thanks!

-mato

[1] Referenced here http://www.da-cha.jp/letsnote as "A patch to handle CD on/off button(need to merge)" (now a dead link)
[2] http://www.netlab.is.tsukuba.ac.jp/~yokota/izumi/panasonic_acpi/,
see the 20070907 version ("includes small hack for CD-ROM drive")

---

drivers/misc/panasonic-laptop.c 2009-01-13 17:04:04.911106197 +0100 renamed from drivers/misc/panasonic-laptop.c.orig 2009-01-13 17:01:53.327106958 +0100 +125 -1

@@ -24,6 +24,8 @@
 *---------------------------------------------------------------------------
 *
 * ChangeLog:
+ *     Jan.13, 2009    Martin Lucina <[email protected]>
+ *             -v0.96  add support for optical drive power in Y and W series
 *     Sep.23, 2008    Harald Welte <[email protected]>
 *             -v0.95  rename driver from drivers/acpi/pcc_acpi.c to
 *                     drivers/misc/panasonic-laptop.c

@@ -127,6 +129,8 @@
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/dmi.h>
 
 
 #ifndef ACPI_HOTKEY_COMPONENT

@@ -219,6 +223,7 @@ struct pcc_acpi {
       struct acpi_device      *device;
       struct input_dev        *input_dev;
       struct backlight_device *backlight;
+       struct platform_device  *platform;
       int                     keymap[KEYMAP_SIZE];
 };
 

@@ -226,6 +231,27 @@ struct pcc_keyinput {
       struct acpi_hotkey      *hotkey;
 };
 
+/* known models with optical drive */
+static struct dmi_system_id pcc_platform_dmi_table[] = {
+       {
+               .ident = "Panasonic Toughbook W Series",
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR,
+                               "Matsushita Electric Industrial Co.,Ltd."),
+                       DMI_MATCH(DMI_PRODUCT_NAME, "CF-W"),
+               },
+       },
+       {
+                .ident = "Panasonic Toughbook Y Series",
+               .matches = {
+                       DMI_MATCH(DMI_SYS_VENDOR,
+                               "Matsushita Electric Industrial Co.,Ltd."),
+                       DMI_MATCH(DMI_PRODUCT_NAME, "CF-Y"),
+               },
+       },
+       { }
+};
+
 /* method access functions */
 static int acpi_pcc_write_sset(struct pcc_acpi *pcc, int func, int val)
 {

@@ -360,6 +386,63 @@ static struct backlight_ops pcc_backligh
       .update_status  = bl_set_status,
 };
 
+/* get optical driver power state */
+
+static int get_optd_power_state(void)
+{
+       acpi_status status;
+       unsigned long long state;
+       int result;
+
+       status = acpi_evaluate_integer(NULL, "\\_SB.STAT", NULL, &state);
+       if (ACPI_FAILURE(status)) {
+               result = -EIO;
+               goto out;
+       }
+       switch (state) {
+       case 0: /* power off */
+               result = 1;
+               break;
+       case 0x0f: /* power on */
+               result = 0;
+               break;
+       default:
+               result = -EIO;
+               break;
+       }
+out:
+       return result;
+}
+
+/* set optical drive power state */
+
+static int set_optd_power_state(int new_state)
+{
+       int state, result;
+       acpi_status status;
+
+       state = get_optd_power_state();
+       if (new_state == state)
+               return 0;
+
+       result = 0;
+       switch (new_state) {
+       case 0: /* power on */
+               status = acpi_evaluate_object (NULL, "\\_SB.FBAY", NULL, NULL);
+               if (ACPI_FAILURE(status))
+                       result = -EIO;
+               break;
+       case 1: /* power off */
+               status = acpi_evaluate_object (NULL, "\\_SB.CDDI", NULL, NULL);
+               if (ACPI_FAILURE(status))
+                       result = -EIO;
+               break;
+       default:
+               result = -EINVAL;
+               break;
+       }
+       return result;
+}
 
 /* sysfs user interface functions */
 

@@ -427,10 +510,29 @@ static ssize_t set_sticky(struct device
       return count;
 }
 
+static ssize_t show_cdpower(struct device *dev, struct device_attribute *attr,
+                           char *buf)
+{
+       return snprintf(buf, PAGE_SIZE, "%d\n", get_optd_power_state());
+}
+
+static ssize_t set_cdpower(struct device *dev, struct device_attribute *attr,
+                          const char *buf, size_t count)
+{
+       int value;
+
+       if (count) {
+               value = simple_strtoul(buf, NULL, 10);
+               set_optd_power_state (value);
+       }
+       return count;
+}
+
 static DEVICE_ATTR(numbatt, S_IRUGO, show_numbatt, NULL);
 static DEVICE_ATTR(lcdtype, S_IRUGO, show_lcdtype, NULL);
 static DEVICE_ATTR(mute, S_IRUGO, show_mute, NULL);
 static DEVICE_ATTR(sticky_key, S_IRUGO | S_IWUSR, show_sticky, set_sticky);
+static DEVICE_ATTR(cdpower, S_IRUGO | S_IWUSR, show_cdpower, set_cdpower);
 
 static struct attribute *pcc_sysfs_entries[] = {
       &dev_attr_numbatt.attr,

@@ -691,8 +793,26 @@ static int acpi_pcc_hotkey_add(struct ac
       if (result)
               goto out_backlight;
 
+       /* platform device initialization */
+       if (!dmi_check_system(pcc_platform_dmi_table)) {
+               pcc->platform = NULL;
+               goto out_no_optd;
+       }
+       pcc->platform = platform_device_register_simple("panasonic", -1,
+               NULL, 0);
+       if (IS_ERR(pcc->platform)) {
+               result = PTR_ERR(pcc->platform);
+               goto out_backlight;
+       }
+       result = device_create_file(&pcc->platform->dev, &dev_attr_cdpower);
+       if (result)
+               goto out_platform;
+
+out_no_optd:
       return 0;
 
+out_platform:
+       platform_device_unregister(pcc->platform);
 out_backlight:
       backlight_device_unregister(pcc->backlight);
 out_notify:

@@ -738,6 +858,11 @@ static int acpi_pcc_hotkey_remove(struct
       if (!device || !pcc)
               return -EINVAL;
 
+       if (pcc->platform) {
+               device_remove_file(&pcc->platform->dev, &dev_attr_cdpower);
+               platform_device_unregister(pcc->platform);
+       }
+
       sysfs_remove_group(&device->dev.kobj, &pcc_attr_group);
 
       backlight_device_unregister(pcc->backlight);
--

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To an end user, writing "0" to enable the device & "1" to disable it sounds counter-intuitive, especially when the sysfs entry is called "cdpower". Is there a reason to not flip that?

3) Please advise on the correct way to propagate an error result from the functions that call the ACPI methods {get,set}optd_power_state() to userspace in the sysfs interface. I couldn't find a straightforward example anywhere.

Add support for power control of the built in optical drive on models with the required ACPI methods present. Tested on Panasonic CF-W4.

Creates an interface in /sys/devices/platform/panasonic/cdpower, to which you can write "1" to switch the drive on, "0" to switch it off or read from to query the current state.

Signed-off-by Martin Lucina <[email protected]>

---

Harald, this should address all the comments in this thread. I've removed the DMI table and enable the code if _SB.{STAT,FBAY,CDDI} are all present.

I've not figured out how to return an actual error from the sysfs show/store functions so I've at least added ACPI_DEBUG_PRINT to print an error if the relevant methods fail.

-mato

Harald,
It's your driver. What do you what to do with this patch.

I'd delegate http://patchwork.kernel.org/patch/2372/
to you, but you don't seem to have a patchwork account yet.

Please don't apply this just yet.

Quoted 19 lines · Martin Lucina

Add support for power control of the built in optical drive on models with the required ACPI methods present. Tested on Panasonic CF-W4.

Creates an interface in /sys/devices/platform/panasonic/cdpower, to which you can write "1" to switch the drive on, "0" to switch it off or read from to query the current state.

Signed-off-by Martin Lucina <[email protected]>

---

Harald, this should address all the comments in this thread. I've removed the DMI table and enable the code if _SB.{STAT,FBAY,CDDI} are all present.

I've not figured out how to return an actual error from the sysfs show/store functions so I've at least added ACPI_DEBUG_PRINT to print an error if the relevant methods fail.

Quoted 1 line

-mato

Harald,
It's your driver. What do you what to do with this patch.

I'd delegate http://patchwork.kernel.org/patch/2372/
to you, but you don't seem to have a patchwork account yet.