ACPI: thinkpad-acpi: add sysfs led class support to thinkpad leds (v3.2)

Add a sysfs led class interface to the led subdriver.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 176 insertions, 7 deletions

diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index af1f2bcb6f66..73b80a7e9b03 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -876,28 +876,63 @@ The cmos command interface is prone to firmware split-brain problems, as
 in newer ThinkPads it is just a compatibility layer.  Do not use it, it is
 exported just as a debug tool.
 
-LED control -- /proc/acpi/ibm/led
----------------------------------
+LED control
+-----------
 
-Some of the LED indicators can be controlled through this feature. The
-available commands are:
+procfs: /proc/acpi/ibm/led
+sysfs attributes: as per led class, see below for names
+
+Some of the LED indicators can be controlled through this feature.  On
+some older ThinkPad models, it is possible to query the status of the
+LED indicators as well.  Newer ThinkPads cannot query the real status
+of the LED indicators.
+
+procfs notes:
+
+The available commands are:
 
         echo '<led number> on' >/proc/acpi/ibm/led
         echo '<led number> off' >/proc/acpi/ibm/led
         echo '<led number> blink' >/proc/acpi/ibm/led
 
 The <led number> range is 0 to 7. The set of LEDs that can be
-controlled varies from model to model. Here is the mapping on the X40:
+controlled varies from model to model. Here is the common ThinkPad
+mapping:
 
         0 - power
         1 - battery (orange)
         2 - battery (green)
-        3 - UltraBase
+        3 - UltraBase/dock
         4 - UltraBay
+        5 - UltraBase battery slot
+        6 - (unknown)
         7 - standby
 
 All of the above can be turned on and off and can be made to blink.
 
+sysfs notes:
+
+The ThinkPad LED sysfs interface is described in detail by the led class
+documentation, in Documentation/leds-class.txt.
+
+The leds are named (in LED ID order, from 0 to 7):
+"tpacpi::power", "tpacpi:orange:batt", "tpacpi:green:batt",
+"tpacpi::dock_active", "tpacpi::bay_active", "tpacpi::dock_batt",
+"tpacpi::unknown_led", "tpacpi::standby".
+
+Due to limitations in the sysfs led class, if the status of the LED
+indicators cannot be read due to an error, thinkpad-acpi will report it as
+a brightness of zero (same as LED off).
+
+If the thinkpad firmware doesn't support reading the current status,
+trying to read the current LED brightness will just return whatever
+brightness was last written to that attribute.
+
+These LEDs can blink using hardware acceleration.  To request that a
+ThinkPad indicator LED should blink in hardware accelerated mode, use the
+"timer" trigger, and leave the delay_on and delay_off parameters set to
+zero (to request hardware acceleration autodetection).
+
 ACPI sounds -- /proc/acpi/ibm/beep
 ----------------------------------
 
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 38a119bd931e..2ab3633f4e56 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -277,6 +277,7 @@ struct tpacpi_led_classdev {
         struct led_classdev led_classdev;
         struct work_struct work;
         enum led_brightness new_brightness;
+        unsigned int led;
 };
 
 /****************************************************************************
@@ -3814,20 +3815,38 @@ TPACPI_HANDLE(led, ec, "SLED",	/* 570 */
            "LED",               /* all others */
            );                   /* R30, R31 */
 
+#define TPACPI_LED_NUMLEDS 8
+static struct tpacpi_led_classdev *tpacpi_leds;
+static enum led_status_t tpacpi_led_state_cache[TPACPI_LED_NUMLEDS];
+static const char const *tpacpi_led_names[TPACPI_LED_NUMLEDS] = {
+        /* there's a limit of 19 chars + NULL before 2.6.26 */
+        "tpacpi::power",
+        "tpacpi:orange:batt",
+        "tpacpi:green:batt",
+        "tpacpi::dock_active",
+        "tpacpi::bay_active",
+        "tpacpi::dock_batt",
+        "tpacpi::unknown_led",
+        "tpacpi::standby",
+};
+
 static int led_get_status(unsigned int led)
 {
         int status;
+        enum led_status_t led_s;
 
         switch (led_supported) {
         case TPACPI_LED_570:
                 if (!acpi_evalf(ec_handle,
                                 &status, "GLED", "dd", 1 << led))
                         return -EIO;
-                return (status == 0)?
+                led_s = (status == 0)?
                                 TPACPI_LED_OFF :
                                 ((status == 1)?
                                         TPACPI_LED_ON :
                                         TPACPI_LED_BLINK);
+                tpacpi_led_state_cache[led] = led_s;
+                return led_s;
         default:
                 return -ENXIO;
         }
@@ -3874,11 +3893,96 @@ static int led_set_status(unsigned int led, enum led_status_t ledstatus)
                 rc = -ENXIO;
         }
 
+        if (!rc)
+                tpacpi_led_state_cache[led] = ledstatus;
+
         return rc;
 }
 
+static void led_sysfs_set_status(unsigned int led,
+                                 enum led_brightness brightness)
+{
+        led_set_status(led,
+                        (brightness == LED_OFF) ?
+                        TPACPI_LED_OFF :
+                        (tpacpi_led_state_cache[led] == TPACPI_LED_BLINK) ?
+                                TPACPI_LED_BLINK : TPACPI_LED_ON);
+}
+
+static void led_set_status_worker(struct work_struct *work)
+{
+        struct tpacpi_led_classdev *data =
+                container_of(work, struct tpacpi_led_classdev, work);
+
+        if (likely(tpacpi_lifecycle == TPACPI_LIFE_RUNNING))
+                led_sysfs_set_status(data->led, data->new_brightness);
+}
+
+static void led_sysfs_set(struct led_classdev *led_cdev,
+                        enum led_brightness brightness)
+{
+        struct tpacpi_led_classdev *data = container_of(led_cdev,
+                             struct tpacpi_led_classdev, led_classdev);
+
+        data->new_brightness = brightness;
+        schedule_work(&data->work);
+}
+
+static int led_sysfs_blink_set(struct led_classdev *led_cdev,
+                        unsigned long *delay_on, unsigned long *delay_off)
+{
+        struct tpacpi_led_classdev *data = container_of(led_cdev,
+                             struct tpacpi_led_classdev, led_classdev);
+
+        /* Can we choose the flash rate? */
+        if (*delay_on == 0 && *delay_off == 0) {
+                /* yes. set them to the hardware blink rate (1 Hz) */
+                *delay_on = 500; /* ms */
+                *delay_off = 500; /* ms */
+        } else if ((*delay_on != 500) || (*delay_off != 500))
+                return -EINVAL;
+
+        data->new_brightness = TPACPI_LED_BLINK;
+        schedule_work(&data->work);
+
+        return 0;
+}
+
+static enum led_brightness led_sysfs_get(struct led_classdev *led_cdev)
+{
+        int rc;
+
+        struct tpacpi_led_classdev *data = container_of(led_cdev,
+                             struct tpacpi_led_classdev, led_classdev);
+
+        rc = led_get_status(data->led);
+
+        if (rc == TPACPI_LED_OFF || rc < 0)
+                rc = LED_OFF;   /* no error handling in led class :( */
+        else
+                rc = LED_FULL;
+
+        return rc;
+}
+
+static void led_exit(void)
+{
+        unsigned int i;
+
+        for (i = 0; i < TPACPI_LED_NUMLEDS; i++) {
+                if (tpacpi_leds[i].led_classdev.name)
+                        led_classdev_unregister(&tpacpi_leds[i].led_classdev);
+        }
+
+        kfree(tpacpi_leds);
+        tpacpi_leds = NULL;
+}
+
 static int __init led_init(struct ibm_init_struct *iibm)
 {
+        unsigned int i;
+        int rc;
+
         vdbg_printk(TPACPI_DBG_INIT, "initializing LED subdriver\n");
 
         TPACPI_ACPIHANDLE_INIT(led);
@@ -3899,6 +4003,35 @@ static int __init led_init(struct ibm_init_struct *iibm)
         vdbg_printk(TPACPI_DBG_INIT, "LED commands are %s, mode %d\n",
                 str_supported(led_supported), led_supported);
 
+        tpacpi_leds = kzalloc(sizeof(*tpacpi_leds) * TPACPI_LED_NUMLEDS,
+                              GFP_KERNEL);
+        if (!tpacpi_leds) {
+                printk(TPACPI_ERR "Out of memory for LED data\n");
+                return -ENOMEM;
+        }
+
+        for (i = 0; i < TPACPI_LED_NUMLEDS; i++) {
+                tpacpi_leds[i].led = i;
+
+                tpacpi_leds[i].led_classdev.brightness_set = &led_sysfs_set;
+                tpacpi_leds[i].led_classdev.blink_set = &led_sysfs_blink_set;
+                if (led_supported == TPACPI_LED_570)
+                        tpacpi_leds[i].led_classdev.brightness_get =
+                                                        &led_sysfs_get;
+
+                tpacpi_leds[i].led_classdev.name = tpacpi_led_names[i];
+
+                INIT_WORK(&tpacpi_leds[i].work, led_set_status_worker);
+
+                rc = led_classdev_register(&tpacpi_pdev->dev,
+                                           &tpacpi_leds[i].led_classdev);
+                if (rc < 0) {
+                        tpacpi_leds[i].led_classdev.name = NULL;
+                        led_exit();
+                        return rc;
+                }
+        }
+
         return (led_supported != TPACPI_LED_NONE)? 0 : 1;
 }
 
@@ -3969,6 +4102,7 @@ static struct ibm_struct led_driver_data = {
         .name = "led",
         .read = led_read,
         .write = led_write,
+        .exit = led_exit,
 };
 
 /*************************************************************************