x86, olpc-xo1-sci: Add lid switch functionality

Configure the XO-1's lid switch GPIO to trigger an SCI interrupt,
and correctly expose this input device which can be used as a wakeup
source.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-9-git-send-email-dsd@laptop.org
Acked-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

3 files changed, 208 insertions, 1 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 88889106ac9b..350ccbb4d650 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2090,6 +2090,7 @@ config OLPC_XO1_SCI
            - EC-driven system wakeups
            - Power button
            - Ebook switch
+           - Lid switch
 
 endif # X86_32
 
diff --git a/arch/x86/platform/olpc/olpc-xo1-sci.c b/arch/x86/platform/olpc/olpc-xo1-sci.c
index 63f50506078b..ad0670bca833 100644
--- a/arch/x86/platform/olpc/olpc-xo1-sci.c
+++ b/arch/x86/platform/olpc/olpc-xo1-sci.c
@@ -32,9 +32,26 @@
 static unsigned long acpi_base;
 static struct input_dev *power_button_idev;
 static struct input_dev *ebook_switch_idev;
+static struct input_dev *lid_switch_idev;
 
 static int sci_irq;
 
+static bool lid_open;
+static bool lid_inverted;
+static int lid_wake_mode;
+
+enum lid_wake_modes {
+        LID_WAKE_ALWAYS,
+        LID_WAKE_OPEN,
+        LID_WAKE_CLOSE,
+};
+
+static const char * const lid_wake_mode_names[] = {
+        [LID_WAKE_ALWAYS] = "always",
+        [LID_WAKE_OPEN] = "open",
+        [LID_WAKE_CLOSE] = "close",
+};
+
 /* Report current ebook switch state through input layer */
 static void send_ebook_state(void)
 {
@@ -49,6 +66,70 @@ static void send_ebook_state(void)
         input_sync(ebook_switch_idev);
 }
 
+static void flip_lid_inverter(void)
+{
+        /* gpio is high; invert so we'll get l->h event interrupt */
+        if (lid_inverted)
+                cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_INPUT_INVERT);
+        else
+                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_INPUT_INVERT);
+        lid_inverted = !lid_inverted;
+}
+
+static void detect_lid_state(void)
+{
+        /*
+         * the edge detector hookup on the gpio inputs on the geode is
+         * odd, to say the least.  See http://dev.laptop.org/ticket/5703
+         * for details, but in a nutshell:  we don't use the edge
+         * detectors.  instead, we make use of an anomoly:  with the both
+         * edge detectors turned off, we still get an edge event on a
+         * positive edge transition.  to take advantage of this, we use the
+         * front-end inverter to ensure that that's the edge we're always
+         * going to see next.
+         */
+
+        int state;
+
+        state = cs5535_gpio_isset(OLPC_GPIO_LID, GPIO_READ_BACK);
+        lid_open = !state ^ !lid_inverted; /* x ^^ y */
+        if (!state)
+                return;
+
+        flip_lid_inverter();
+}
+
+/* Report current lid switch state through input layer */
+static void send_lid_state(void)
+{
+        input_report_switch(lid_switch_idev, SW_LID, !lid_open);
+        input_sync(lid_switch_idev);
+}
+
+static ssize_t lid_wake_mode_show(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
+{
+        const char *mode = lid_wake_mode_names[lid_wake_mode];
+        return sprintf(buf, "%s\n", mode);
+}
+static ssize_t lid_wake_mode_set(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf, size_t count)
+{
+        int i;
+        for (i = 0; i < ARRAY_SIZE(lid_wake_mode_names); i++) {
+                const char *mode = lid_wake_mode_names[i];
+                if (strlen(mode) != count || strncasecmp(mode, buf, count))
+                        continue;
+
+                lid_wake_mode = i;
+                return count;
+        }
+        return -EINVAL;
+}
+static DEVICE_ATTR(lid_wake_mode, S_IWUSR | S_IRUGO, lid_wake_mode_show,
+                   lid_wake_mode_set);
+
 /*
  * Process all items in the EC's SCI queue.
  *
@@ -111,6 +192,11 @@ static irqreturn_t xo1_sci_intr(int irq, void *dev_id)
                 schedule_work(&sci_work);
         }
 
+        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_STS);
+        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_STS);
+        detect_lid_state();
+        send_lid_state();
+
         return IRQ_HANDLED;
 }
 
@@ -126,11 +212,32 @@ static int xo1_sci_suspend(struct platform_device *pdev, pm_message_t state)
         else
                 olpc_ec_wakeup_clear(EC_SCI_SRC_EBOOK);
 
+        if (!device_may_wakeup(&lid_switch_idev->dev)) {
+                cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
+        } else if ((lid_open && lid_wake_mode == LID_WAKE_OPEN) ||
+                   (!lid_open && lid_wake_mode == LID_WAKE_CLOSE)) {
+                flip_lid_inverter();
+
+                /* we may have just caused an event */
+                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_STS);
+                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_STS);
+
+                cs5535_gpio_set(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
+        }
+
         return 0;
 }
 
 static int xo1_sci_resume(struct platform_device *pdev)
 {
+        /*
+         * We don't know what may have happened while we were asleep.
+         * Reestablish our lid setup so we're sure to catch all transitions.
+         */
+        detect_lid_state();
+        send_lid_state();
+        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
+
         /* Enable all EC events */
         olpc_ec_mask_write(EC_SCI_SRC_ALL);
         return 0;
@@ -221,6 +328,43 @@ static void free_ec_sci(void)
         gpio_free(OLPC_GPIO_ECSCI);
 }
 
+static int __devinit setup_lid_events(void)
+{
+        int r;
+
+        r = gpio_request(OLPC_GPIO_LID, "OLPC-LID");
+        if (r)
+                return r;
+
+        gpio_direction_input(OLPC_GPIO_LID);
+
+        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_INPUT_INVERT);
+        lid_inverted = 0;
+
+        /* Clear edge detection and event enable for now */
+        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
+        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_EN);
+        cs5535_gpio_clear(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_EN);
+        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_NEGATIVE_EDGE_STS);
+        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_POSITIVE_EDGE_STS);
+
+        /* Set the LID to cause an PME event on group 6 */
+        cs5535_gpio_setup_event(OLPC_GPIO_LID, 6, 1);
+
+        /* Set PME group 6 to fire the SCI interrupt */
+        cs5535_gpio_set_irq(6, sci_irq);
+
+        /* Enable the event */
+        cs5535_gpio_set(OLPC_GPIO_LID, GPIO_EVENTS_ENABLE);
+
+        return 0;
+}
+
+static void free_lid_events(void)
+{
+        gpio_free(OLPC_GPIO_LID);
+}
+
 static int __devinit setup_power_button(struct platform_device *pdev)
 {
         int r;
@@ -283,6 +427,50 @@ static void free_ebook_switch(void)
         input_free_device(ebook_switch_idev);
 }
 
+static int __devinit setup_lid_switch(struct platform_device *pdev)
+{
+        int r;
+
+        lid_switch_idev = input_allocate_device();
+        if (!lid_switch_idev)
+                return -ENOMEM;
+
+        lid_switch_idev->name = "Lid Switch";
+        lid_switch_idev->phys = DRV_NAME "/input2";
+        set_bit(EV_SW, lid_switch_idev->evbit);
+        set_bit(SW_LID, lid_switch_idev->swbit);
+
+        lid_switch_idev->dev.parent = &pdev->dev;
+        device_set_wakeup_capable(&lid_switch_idev->dev, true);
+
+        r = input_register_device(lid_switch_idev);
+        if (r) {
+                dev_err(&pdev->dev, "failed to register lid switch: %d\n", r);
+                goto err_register;
+        }
+
+        r = device_create_file(&lid_switch_idev->dev, &dev_attr_lid_wake_mode);
+        if (r) {
+                dev_err(&pdev->dev, "failed to create wake mode attr: %d\n", r);
+                goto err_create_attr;
+        }
+
+        return 0;
+
+err_create_attr:
+        input_unregister_device(lid_switch_idev);
+err_register:
+        input_free_device(lid_switch_idev);
+        return r;
+}
+
+static void free_lid_switch(void)
+{
+        device_remove_file(&lid_switch_idev->dev, &dev_attr_lid_wake_mode);
+        input_unregister_device(lid_switch_idev);
+        input_free_device(lid_switch_idev);
+}
+
 static int __devinit xo1_sci_probe(struct platform_device *pdev)
 {
         struct resource *res;
@@ -311,12 +499,21 @@ static int __devinit xo1_sci_probe(struct platform_device *pdev)
         if (r)
                 goto err_ebook;
 
+        r = setup_lid_switch(pdev);
+        if (r)
+                goto err_lid;
+
+        r = setup_lid_events();
+        if (r)
+                goto err_lidevt;
+
         r = setup_ec_sci();
         if (r)
                 goto err_ecsci;
 
         /* Enable PME generation for EC-generated events */
-        outl(CS5536_GPIOM7_PME_EN, acpi_base + CS5536_PM_GPE0_EN);
+        outl(CS5536_GPIOM6_PME_EN | CS5536_GPIOM7_PME_EN,
+                acpi_base + CS5536_PM_GPE0_EN);
 
         /* Clear pending events */
         outl(0xffffffff, acpi_base + CS5536_PM_GPE0_STS);
@@ -324,6 +521,8 @@ static int __devinit xo1_sci_probe(struct platform_device *pdev)
 
         /* Initial sync */
         send_ebook_state();
+        detect_lid_state();
+        send_lid_state();
 
         r = setup_sci_interrupt(pdev);
         if (r)
@@ -337,6 +536,10 @@ static int __devinit xo1_sci_probe(struct platform_device *pdev)
 err_sci:
         free_ec_sci();
 err_ecsci:
+        free_lid_events();
+err_lidevt:
+        free_lid_switch();
+err_lid:
         free_ebook_switch();
 err_ebook:
         free_power_button();
@@ -349,6 +552,8 @@ static int __devexit xo1_sci_remove(struct platform_device *pdev)
         free_irq(sci_irq, pdev);
         cancel_work_sync(&sci_work);
         free_ec_sci();
+        free_lid_events();
+        free_lid_switch();
         free_ebook_switch();
         free_power_button();
         acpi_base = 0;
diff --git a/include/linux/cs5535.h b/include/linux/cs5535.h
index d7e9a7f6ddb0..72954c6bf5d6 100644
--- a/include/linux/cs5535.h
+++ b/include/linux/cs5535.h
@@ -102,6 +102,7 @@ static inline int cs5535_pic_unreqz_select_high(unsigned int group,
 
 /* CS5536_PM_GPE0_EN bits */
 #define CS5536_GPIOM7_PME_EN    (1 << 31)
+#define CS5536_GPIOM6_PME_EN    (1 << 30)
 
 /* VSA2 magic values */
 #define VSA_VRC_INDEX           0xAC1C