powerpc/cell: Add support for power button of future IBM cell blades

This patch adds support for the power button on future IBM cell blades.
It actually doesn't shut down the machine. Instead it exposes an
input device /dev/input/event0 to userspace which sends KEY_POWER
if power button has been pressed.
haldaemon actually recognizes the button, so a plattform independent acpid
replacement should handle it correctly.

Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 127 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/Kconfig b/arch/powerpc/platforms/cell/Kconfig
index 2d1957bc450d..c14d7d8d96c8 100644
--- a/arch/powerpc/platforms/cell/Kconfig
+++ b/arch/powerpc/platforms/cell/Kconfig
@@ -91,6 +91,14 @@ config PPC_IBM_CELL_RESETBUTTON
           Support Pinhole Resetbutton on IBM Cell blades.
           This adds a method to trigger system reset via front panel pinhole button.
 
+config PPC_IBM_CELL_POWERBUTTON
+        tristate "IBM Cell Blade power button"
+        depends on PPC_IBM_CELL_BLADE && PPC_PMI && INPUT_EVDEV
+        default y
+        help
+          Support Powerbutton on IBM Cell blades.
+          This will enable the powerbutton as an input device.
+
 config CBE_THERM
         tristate "CBE thermal support"
         default m
diff --git a/arch/powerpc/platforms/cell/Makefile b/arch/powerpc/platforms/cell/Makefile
index 7fcf09bd80b8..7fd830872c43 100644
--- a/arch/powerpc/platforms/cell/Makefile
+++ b/arch/powerpc/platforms/cell/Makefile
@@ -10,6 +10,8 @@ obj-$(CONFIG_CBE_CPUFREQ)		+= cbe-cpufreq.o
 cbe-cpufreq-y                           += cbe_cpufreq_pervasive.o cbe_cpufreq.o
 obj-$(CONFIG_CBE_CPUFREQ_SPU_GOVERNOR)  += cpufreq_spudemand.o
 
+obj-$(CONFIG_PPC_IBM_CELL_POWERBUTTON)  += cbe_powerbutton.o
+
 ifeq ($(CONFIG_SMP),y)
 obj-$(CONFIG_PPC_CELL_NATIVE)           += smp.o
 endif
diff --git a/arch/powerpc/platforms/cell/cbe_powerbutton.c b/arch/powerpc/platforms/cell/cbe_powerbutton.c
new file mode 100644
index 000000000000..dcddaa5fcb66
--- /dev/null
+++ b/arch/powerpc/platforms/cell/cbe_powerbutton.c
@@ -0,0 +1,117 @@
+/*
+ * driver for powerbutton on IBM cell blades
+ *
+ * (C) Copyright IBM Corp. 2005-2008
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * 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, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <asm/pmi.h>
+#include <asm/prom.h>
+
+static struct input_dev *button_dev;
+static struct platform_device *button_pdev;
+
+static void cbe_powerbutton_handle_pmi(pmi_message_t pmi_msg)
+{
+        BUG_ON(pmi_msg.type != PMI_TYPE_POWER_BUTTON);
+
+        input_report_key(button_dev, KEY_POWER, 1);
+        input_sync(button_dev);
+        input_report_key(button_dev, KEY_POWER, 0);
+        input_sync(button_dev);
+}
+
+static struct pmi_handler cbe_pmi_handler = {
+        .type                   = PMI_TYPE_POWER_BUTTON,
+        .handle_pmi_message     = cbe_powerbutton_handle_pmi,
+};
+
+static int __init cbe_powerbutton_init(void)
+{
+        int ret = 0;
+        struct input_dev *dev;
+
+        if (!machine_is_compatible("IBM,CBPLUS-1.0")) {
+                printk(KERN_ERR "%s: Not a cell blade.\n", __func__);
+                ret = -ENODEV;
+                goto out;
+        }
+
+        dev = input_allocate_device();
+        if (!dev) {
+                ret = -ENOMEM;
+                printk(KERN_ERR "%s: Not enough memory.\n", __func__);
+                goto out;
+        }
+
+        set_bit(EV_KEY, dev->evbit);
+        set_bit(KEY_POWER, dev->keybit);
+
+        dev->name = "Power Button";
+        dev->id.bustype = BUS_HOST;
+
+        /* this makes the button look like an acpi power button
+         * no clue whether anyone relies on that though */
+        dev->id.product = 0x02;
+        dev->phys = "LNXPWRBN/button/input0";
+
+        button_pdev = platform_device_register_simple("power_button", 0, NULL, 0);
+        if (IS_ERR(button_pdev)) {
+                ret = PTR_ERR(button_pdev);
+                goto out_free_input;
+        }
+
+        dev->dev.parent = &button_pdev->dev;
+        ret = input_register_device(dev);
+        if (ret) {
+                printk(KERN_ERR "%s: Failed to register device\n", __func__);
+                goto out_free_pdev;
+        }
+
+        button_dev = dev;
+
+        ret = pmi_register_handler(&cbe_pmi_handler);
+        if (ret) {
+                printk(KERN_ERR "%s: Failed to register with pmi.\n", __func__);
+                goto out_free_pdev;
+        }
+
+        goto out;
+
+out_free_pdev:
+        platform_device_unregister(button_pdev);
+out_free_input:
+        input_free_device(dev);
+out:
+        return ret;
+}
+
+static void __exit cbe_powerbutton_exit(void)
+{
+        pmi_unregister_handler(&cbe_pmi_handler);
+        platform_device_unregister(button_pdev);
+        input_free_device(button_dev);
+}
+
+module_init(cbe_powerbutton_init);
+module_exit(cbe_powerbutton_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");