x86, olpc-xo1-sci: Add GPE handler and ebook switch functionality

The EC in the OLPC XO-1 delivers GPE events to provide various
notifications. Add the basic code for GPE/EC event processing and
enable the ebook switch, which can be used as a wakeup source.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-8-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, 187 insertions, 3 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 66b7b9d519d..88889106ac9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2087,7 +2087,9 @@ config OLPC_XO1_SCI
         select MFD_CORE
         ---help---
           Add support for SCI-based features of the OLPC XO-1 laptop:
+           - EC-driven system wakeups
            - Power button
+           - Ebook switch
 
 endif # X86_32
 
diff --git a/arch/x86/include/asm/olpc.h b/arch/x86/include/asm/olpc.h
index 0e56d01907f..87bdbca72f9 100644
--- a/arch/x86/include/asm/olpc.h
+++ b/arch/x86/include/asm/olpc.h
@@ -111,6 +111,7 @@ extern int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 #define EC_WRITE_SCI_MASK               0x1b
 #define EC_WAKE_UP_WLAN                 0x24
 #define EC_WLAN_LEAVE_RESET             0x25
+#define EC_READ_EB_MODE                 0x2a
 #define EC_SET_SCI_INHIBIT              0x32
 #define EC_SET_SCI_INHIBIT_RELEASE      0x34
 #define EC_WLAN_ENTER_RESET             0x35
@@ -144,7 +145,7 @@ extern int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 #define OLPC_GPIO_SMB_CLK      14
 #define OLPC_GPIO_SMB_DATA     15
 #define OLPC_GPIO_WORKAUX       geode_gpio(24)
-#define OLPC_GPIO_LID           geode_gpio(26)
-#define OLPC_GPIO_ECSCI         geode_gpio(27)
+#define OLPC_GPIO_LID           26
+#define OLPC_GPIO_ECSCI         27
 
 #endif /* _ASM_X86_OLPC_H */
diff --git a/arch/x86/platform/olpc/olpc-xo1-sci.c b/arch/x86/platform/olpc/olpc-xo1-sci.c
index 8fbf961dae8..63f50506078 100644
--- a/arch/x86/platform/olpc/olpc-xo1-sci.c
+++ b/arch/x86/platform/olpc/olpc-xo1-sci.c
@@ -12,12 +12,15 @@
  */
 
 #include <linux/cs5535.h>
+#include <linux/device.h>
+#include <linux/gpio.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/mfd/core.h>
 #include <linux/suspend.h>
+#include <linux/workqueue.h>
 
 #include <asm/io.h>
 #include <asm/msr.h>
@@ -28,8 +31,60 @@
 
 static unsigned long acpi_base;
 static struct input_dev *power_button_idev;
+static struct input_dev *ebook_switch_idev;
+
 static int sci_irq;
 
+/* Report current ebook switch state through input layer */
+static void send_ebook_state(void)
+{
+        unsigned char state;
+
+        if (olpc_ec_cmd(EC_READ_EB_MODE, NULL, 0, &state, 1)) {
+                pr_err(PFX "failed to get ebook state\n");
+                return;
+        }
+
+        input_report_switch(ebook_switch_idev, SW_TABLET_MODE, state);
+        input_sync(ebook_switch_idev);
+}
+
+/*
+ * Process all items in the EC's SCI queue.
+ *
+ * This is handled in a workqueue because olpc_ec_cmd can be slow (and
+ * can even timeout).
+ *
+ * If propagate_events is false, the queue is drained without events being
+ * generated for the interrupts.
+ */
+static void process_sci_queue(bool propagate_events)
+{
+        int r;
+        u16 data;
+
+        do {
+                r = olpc_ec_sci_query(&data);
+                if (r || !data)
+                        break;
+
+                pr_debug(PFX "SCI 0x%x received\n", data);
+
+                if (data == EC_SCI_SRC_EBOOK && propagate_events)
+                        send_ebook_state();
+        } while (data);
+
+        if (r)
+                pr_err(PFX "Failed to clear SCI queue");
+}
+
+static void process_sci_queue_work(struct work_struct *work)
+{
+        process_sci_queue(true);
+}
+
+static DECLARE_WORK(sci_work, process_sci_queue_work);
+
 static irqreturn_t xo1_sci_intr(int irq, void *dev_id)
 {
         struct platform_device *pdev = dev_id;
@@ -51,6 +106,11 @@ static irqreturn_t xo1_sci_intr(int irq, void *dev_id)
                 input_sync(power_button_idev);
         }
 
+        if (gpe & CS5536_GPIOM7_PME_FLAG) { /* EC GPIO */
+                cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_NEGATIVE_EDGE_STS);
+                schedule_work(&sci_work);
+        }
+
         return IRQ_HANDLED;
 }
 
@@ -60,6 +120,19 @@ static int xo1_sci_suspend(struct platform_device *pdev, pm_message_t state)
                 olpc_xo1_pm_wakeup_set(CS5536_PM_PWRBTN);
         else
                 olpc_xo1_pm_wakeup_clear(CS5536_PM_PWRBTN);
+
+        if (device_may_wakeup(&ebook_switch_idev->dev))
+                olpc_ec_wakeup_set(EC_SCI_SRC_EBOOK);
+        else
+                olpc_ec_wakeup_clear(EC_SCI_SRC_EBOOK);
+
+        return 0;
+}
+
+static int xo1_sci_resume(struct platform_device *pdev)
+{
+        /* Enable all EC events */
+        olpc_ec_mask_write(EC_SCI_SRC_ALL);
         return 0;
 }
 
@@ -104,6 +177,50 @@ static int __devinit setup_sci_interrupt(struct platform_device *pdev)
         return r;
 }
 
+static int __devinit setup_ec_sci(void)
+{
+        int r;
+
+        r = gpio_request(OLPC_GPIO_ECSCI, "OLPC-ECSCI");
+        if (r)
+                return r;
+
+        gpio_direction_input(OLPC_GPIO_ECSCI);
+
+        /* Clear pending EC SCI events */
+        cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_NEGATIVE_EDGE_STS);
+        cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_POSITIVE_EDGE_STS);
+
+        /*
+         * Enable EC SCI events, and map them to both a PME and the SCI
+         * interrupt.
+         *
+         * Ordinarily, in addition to functioning as GPIOs, Geode GPIOs can
+         * be mapped to regular interrupts *or* Geode-specific Power
+         * Management Events (PMEs) - events that bring the system out of
+         * suspend. In this case, we want both of those things - the system
+         * wakeup, *and* the ability to get an interrupt when an event occurs.
+         *
+         * To achieve this, we map the GPIO to a PME, and then we use one
+         * of the many generic knobs on the CS5535 PIC to additionally map the
+         * PME to the regular SCI interrupt line.
+         */
+        cs5535_gpio_set(OLPC_GPIO_ECSCI, GPIO_EVENTS_ENABLE);
+
+        /* Set the SCI to cause a PME event on group 7 */
+        cs5535_gpio_setup_event(OLPC_GPIO_ECSCI, 7, 1);
+
+        /* And have group 7 also fire the SCI interrupt */
+        cs5535_pic_unreqz_select_high(7, sci_irq);
+
+        return 0;
+}
+
+static void free_ec_sci(void)
+{
+        gpio_free(OLPC_GPIO_ECSCI);
+}
+
 static int __devinit setup_power_button(struct platform_device *pdev)
 {
         int r;
@@ -135,6 +252,37 @@ static void free_power_button(void)
         input_free_device(power_button_idev);
 }
 
+static int __devinit setup_ebook_switch(struct platform_device *pdev)
+{
+        int r;
+
+        ebook_switch_idev = input_allocate_device();
+        if (!ebook_switch_idev)
+                return -ENOMEM;
+
+        ebook_switch_idev->name = "EBook Switch";
+        ebook_switch_idev->phys = DRV_NAME "/input1";
+        set_bit(EV_SW, ebook_switch_idev->evbit);
+        set_bit(SW_TABLET_MODE, ebook_switch_idev->swbit);
+
+        ebook_switch_idev->dev.parent = &pdev->dev;
+        device_set_wakeup_capable(&ebook_switch_idev->dev, true);
+
+        r = input_register_device(ebook_switch_idev);
+        if (r) {
+                dev_err(&pdev->dev, "failed to register ebook switch: %d\n", r);
+                input_free_device(ebook_switch_idev);
+        }
+
+        return r;
+}
+
+static void free_ebook_switch(void)
+{
+        input_unregister_device(ebook_switch_idev);
+        input_free_device(ebook_switch_idev);
+}
+
 static int __devinit xo1_sci_probe(struct platform_device *pdev)
 {
         struct resource *res;
@@ -159,10 +307,39 @@ static int __devinit xo1_sci_probe(struct platform_device *pdev)
         if (r)
                 return r;
 
+        r = setup_ebook_switch(pdev);
+        if (r)
+                goto err_ebook;
+
+        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);
+
+        /* Clear pending events */
+        outl(0xffffffff, acpi_base + CS5536_PM_GPE0_STS);
+        process_sci_queue(false);
+
+        /* Initial sync */
+        send_ebook_state();
+
         r = setup_sci_interrupt(pdev);
         if (r)
-                free_power_button();
+                goto err_sci;
 
+        /* Enable all EC events */
+        olpc_ec_mask_write(EC_SCI_SRC_ALL);
+
+        return r;
+
+err_sci:
+        free_ec_sci();
+err_ecsci:
+        free_ebook_switch();
+err_ebook:
+        free_power_button();
         return r;
 }
 
@@ -170,6 +347,9 @@ static int __devexit xo1_sci_remove(struct platform_device *pdev)
 {
         mfd_cell_disable(pdev);
         free_irq(sci_irq, pdev);
+        cancel_work_sync(&sci_work);
+        free_ec_sci();
+        free_ebook_switch();
         free_power_button();
         acpi_base = 0;
         return 0;
@@ -182,6 +362,7 @@ static struct platform_driver xo1_sci_driver = {
         .probe = xo1_sci_probe,
         .remove = __devexit_p(xo1_sci_remove),
         .suspend = xo1_sci_suspend,
+        .resume = xo1_sci_resume,
 };
 
 static int __init xo1_sci_init(void)