x86, olpc: Add XO-1.5 SCI driver

Add a driver for the ACPI-based EC event interface found on the
OLPC XO-1.5 laptop. This enables notification of battery/AC power events,
and enables various devices to be used as wakeup sources through regular
ACPI mechanisms.

This driver can't be built as a module, because some drivers need to know
at boot-time if SCI-based functionality is available via
olpc_ec_wakeup_available().

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-12-git-send-email-dsd@laptop.org
Acked-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

4 files changed, 187 insertions, 0 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0a9d573a2f9d..8af5ba8a36b7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2101,6 +2101,15 @@ config OLPC_XO1_SCI
            - AC adapter status updates
            - Battery status updates
 
+config OLPC_XO15_SCI
+        bool "OLPC XO-1.5 SCI extras"
+        depends on OLPC && ACPI && POWER_SUPPLY
+        ---help---
+          Add support for SCI-based features of the OLPC XO-1.5 laptop:
+           - EC-driven system wakeups
+           - AC adapter status updates
+           - Battery status updates
+
 endif # X86_32
 
 config AMD_NB
diff --git a/arch/x86/platform/olpc/Makefile b/arch/x86/platform/olpc/Makefile
index 8922b9b3cd7a..fd332c533947 100644
--- a/arch/x86/platform/olpc/Makefile
+++ b/arch/x86/platform/olpc/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_OLPC)		+= olpc.o olpc_ofw.o olpc_dt.o
 obj-$(CONFIG_OLPC_XO1_PM)               += olpc-xo1-pm.o xo1-wakeup.o
 obj-$(CONFIG_OLPC_XO1_RTC)      += olpc-xo1-rtc.o
 obj-$(CONFIG_OLPC_XO1_SCI)      += olpc-xo1-sci.o
+obj-$(CONFIG_OLPC_XO15_SCI)     += olpc-xo15-sci.o
diff --git a/arch/x86/platform/olpc/olpc-xo15-sci.c b/arch/x86/platform/olpc/olpc-xo15-sci.c
new file mode 100644
index 000000000000..a5990ebadbe4
--- /dev/null
+++ b/arch/x86/platform/olpc/olpc-xo15-sci.c
@@ -0,0 +1,168 @@
+/*
+ * Support for OLPC XO-1.5 System Control Interrupts (SCI)
+ *
+ * Copyright (C) 2009-2010 One Laptop per Child
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/power_supply.h>
+
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+#include <asm/olpc.h>
+
+#define DRV_NAME                        "olpc-xo15-sci"
+#define PFX                             DRV_NAME ": "
+#define XO15_SCI_CLASS                  DRV_NAME
+#define XO15_SCI_DEVICE_NAME            "OLPC XO-1.5 SCI"
+
+static unsigned long xo15_sci_gpe;
+
+static void battery_status_changed(void)
+{
+        struct power_supply *psy = power_supply_get_by_name("olpc-battery");
+
+        if (psy) {
+                power_supply_changed(psy);
+                put_device(psy->dev);
+        }
+}
+
+static void ac_status_changed(void)
+{
+        struct power_supply *psy = power_supply_get_by_name("olpc-ac");
+
+        if (psy) {
+                power_supply_changed(psy);
+                put_device(psy->dev);
+        }
+}
+
+static void process_sci_queue(void)
+{
+        u16 data;
+        int r;
+
+        do {
+                r = olpc_ec_sci_query(&data);
+                if (r || !data)
+                        break;
+
+                pr_debug(PFX "SCI 0x%x received\n", data);
+
+                switch (data) {
+                case EC_SCI_SRC_BATERR:
+                case EC_SCI_SRC_BATSOC:
+                case EC_SCI_SRC_BATTERY:
+                case EC_SCI_SRC_BATCRIT:
+                        battery_status_changed();
+                        break;
+                case EC_SCI_SRC_ACPWR:
+                        ac_status_changed();
+                        break;
+                }
+        } 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();
+}
+
+static DECLARE_WORK(sci_work, process_sci_queue_work);
+
+static u32 xo15_sci_gpe_handler(acpi_handle gpe_device, u32 gpe, void *context)
+{
+        schedule_work(&sci_work);
+        return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
+}
+
+static int xo15_sci_add(struct acpi_device *device)
+{
+        unsigned long long tmp;
+        acpi_status status;
+
+        if (!device)
+                return -EINVAL;
+
+        strcpy(acpi_device_name(device), XO15_SCI_DEVICE_NAME);
+        strcpy(acpi_device_class(device), XO15_SCI_CLASS);
+
+        /* Get GPE bit assignment (EC events). */
+        status = acpi_evaluate_integer(device->handle, "_GPE", NULL, &tmp);
+        if (ACPI_FAILURE(status))
+                return -EINVAL;
+
+        xo15_sci_gpe = tmp;
+        status = acpi_install_gpe_handler(NULL, xo15_sci_gpe,
+                                          ACPI_GPE_EDGE_TRIGGERED,
+                                          xo15_sci_gpe_handler, device);
+        if (ACPI_FAILURE(status))
+                return -ENODEV;
+
+        dev_info(&device->dev, "Initialized, GPE = 0x%lx\n", xo15_sci_gpe);
+
+        /* Flush queue, and enable all SCI events */
+        process_sci_queue();
+        olpc_ec_mask_write(EC_SCI_SRC_ALL);
+
+        acpi_enable_gpe(NULL, xo15_sci_gpe);
+
+        /* Enable wake-on-EC */
+        if (device->wakeup.flags.valid)
+                device_set_wakeup_enable(&device->dev, true);
+
+        return 0;
+}
+
+static int xo15_sci_remove(struct acpi_device *device, int type)
+{
+        acpi_disable_gpe(NULL, xo15_sci_gpe);
+        acpi_remove_gpe_handler(NULL, xo15_sci_gpe, xo15_sci_gpe_handler);
+        cancel_work_sync(&sci_work);
+        return 0;
+}
+
+static int xo15_sci_resume(struct acpi_device *device)
+{
+        /* Enable all EC events */
+        olpc_ec_mask_write(EC_SCI_SRC_ALL);
+
+        /* Power/battery status might have changed */
+        battery_status_changed();
+        ac_status_changed();
+
+        return 0;
+}
+
+static const struct acpi_device_id xo15_sci_device_ids[] = {
+        {"XO15EC", 0},
+        {"", 0},
+};
+
+static struct acpi_driver xo15_sci_drv = {
+        .name = DRV_NAME,
+        .class = XO15_SCI_CLASS,
+        .ids = xo15_sci_device_ids,
+        .ops = {
+                .add = xo15_sci_add,
+                .remove = xo15_sci_remove,
+                .resume = xo15_sci_resume,
+        },
+};
+
+static int __init xo15_sci_init(void)
+{
+        return acpi_bus_register_driver(&xo15_sci_drv);
+}
+device_initcall(xo15_sci_init);
diff --git a/arch/x86/platform/olpc/olpc.c b/arch/x86/platform/olpc/olpc.c
index 72fd041762fc..8b9940e78e2f 100644
--- a/arch/x86/platform/olpc/olpc.c
+++ b/arch/x86/platform/olpc/olpc.c
@@ -222,6 +222,15 @@ bool olpc_ec_wakeup_available(void)
                 return true;
 #endif
 
+        /*
+         * XO-1.5 EC wakeups are available when olpc-xo15-sci driver is
+         * compiled in
+         */
+#ifdef CONFIG_OLPC_XO15_SCI
+        if (olpc_platform_info.boardrev >= olpc_board_pre(0xd0)) /* XO-1.5 */
+                return true;
+#endif
+
         return false;
 }
 EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available);