misc: add dell-laptop driver

Add a driver for controlling Dell-specific backlight and rfkill interfaces.
This driver makes use of the dcdbas interface to the Dell firmware to
allow the backlight and rfkill interfaces on Dell systems to be driven
through the standardised sysfs interfaces.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Cc: Ivo van Doorn <ivdoorn@gmail.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 454 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index a01884407fe4..4bb5d4be8105 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1360,6 +1360,11 @@ P:	Maciej W. Rozycki
 M:      macro@linux-mips.org
 S:      Maintained
 
+DELL LAPTOP DRIVER
+P:      Matthew Garrett
+M:      mjg59@srcf.ucam.org
+S:      Maintained
+
 DELL LAPTOP SMM DRIVER
 P:      Massimo Dal Zotto
 M:      dz@debian.org
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index fee7304102af..3949a1c73451 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -498,6 +498,18 @@ config SGI_GRU_DEBUG
         This option enables addition debugging code for the SGI GRU driver. If
         you are unsure, say N.
 
+config DELL_LAPTOP
+        tristate "Dell Laptop Extras (EXPERIMENTAL)"
+        depends on X86
+        depends on DCDBAS
+        depends on EXPERIMENTAL
+        depends on BACKLIGHT_CLASS_DEVICE
+        depends on RFKILL
+        default n
+        ---help---
+        This driver adds support for rfkill and backlight control to Dell
+        laptops.
+
 source "drivers/misc/c2port/Kconfig"
 
 endif # MISC_DEVICES
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 817f7f5ab3bd..5de863a0e395 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_ICS932S401)	+= ics932s401.o
 obj-$(CONFIG_TC1100_WMI)        += tc1100-wmi.o
 obj-$(CONFIG_LKDTM)             += lkdtm.o
 obj-$(CONFIG_TIFM_CORE)         += tifm_core.o
+obj-$(CONFIG_DELL_LAPTOP)       += dell-laptop.o
 obj-$(CONFIG_TIFM_7XX1)         += tifm_7xx1.o
 obj-$(CONFIG_PHANTOM)           += phantom.o
 obj-$(CONFIG_SGI_IOC4)          += ioc4.o
diff --git a/drivers/misc/dell-laptop.c b/drivers/misc/dell-laptop.c
new file mode 100644
index 000000000000..4d33a2068b7a
--- /dev/null
+++ b/drivers/misc/dell-laptop.c
@@ -0,0 +1,436 @@
+/*
+ *  Driver for Dell laptop extras
+ *
+ *  Copyright (c) Red Hat <mjg@redhat.com>
+ *
+ *  Based on documentation in the libsmbios package, Copyright (C) 2005 Dell
+ *  Inc.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/dmi.h>
+#include <linux/io.h>
+#include <linux/rfkill.h>
+#include <linux/power_supply.h>
+#include <linux/acpi.h>
+#include "../firmware/dcdbas.h"
+
+#define BRIGHTNESS_TOKEN 0x7d
+
+/* This structure will be modified by the firmware when we enter
+ * system management mode, hence the volatiles */
+
+struct calling_interface_buffer {
+        u16 class;
+        u16 select;
+        volatile u32 input[4];
+        volatile u32 output[4];
+} __packed;
+
+struct calling_interface_token {
+        u16 tokenID;
+        u16 location;
+        union {
+                u16 value;
+                u16 stringlength;
+        };
+};
+
+struct calling_interface_structure {
+        struct dmi_header header;
+        u16 cmdIOAddress;
+        u8 cmdIOCode;
+        u32 supportedCmds;
+        struct calling_interface_token tokens[];
+} __packed;
+
+static int da_command_address;
+static int da_command_code;
+static int da_num_tokens;
+static struct calling_interface_token *da_tokens;
+
+static struct backlight_device *dell_backlight_device;
+static struct rfkill *wifi_rfkill;
+static struct rfkill *bluetooth_rfkill;
+static struct rfkill *wwan_rfkill;
+
+static const struct dmi_system_id __initdata dell_device_table[] = {
+        {
+                .ident = "Dell laptop",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+                        DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
+                },
+        },
+        { }
+};
+
+static void parse_da_table(const struct dmi_header *dm)
+{
+        /* Final token is a terminator, so we don't want to copy it */
+        int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
+        struct calling_interface_structure *table =
+                container_of(dm, struct calling_interface_structure, header);
+
+        /* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
+           6 bytes of entry */
+
+        if (dm->length < 17)
+                return;
+
+        da_command_address = table->cmdIOAddress;
+        da_command_code = table->cmdIOCode;
+
+        da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
+                             sizeof(struct calling_interface_token),
+                             GFP_KERNEL);
+
+        if (!da_tokens)
+                return;
+
+        memcpy(da_tokens+da_num_tokens, table->tokens,
+               sizeof(struct calling_interface_token) * tokens);
+
+        da_num_tokens += tokens;
+}
+
+static void find_tokens(const struct dmi_header *dm)
+{
+        switch (dm->type) {
+        case 0xd4: /* Indexed IO */
+                break;
+        case 0xd5: /* Protected Area Type 1 */
+                break;
+        case 0xd6: /* Protected Area Type 2 */
+                break;
+        case 0xda: /* Calling interface */
+                parse_da_table(dm);
+                break;
+        }
+}
+
+static int find_token_location(int tokenid)
+{
+        int i;
+        for (i = 0; i < da_num_tokens; i++) {
+                if (da_tokens[i].tokenID == tokenid)
+                        return da_tokens[i].location;
+        }
+
+        return -1;
+}
+
+static struct calling_interface_buffer *
+dell_send_request(struct calling_interface_buffer *buffer, int class,
+                  int select)
+{
+        struct smi_cmd command;
+
+        command.magic = SMI_CMD_MAGIC;
+        command.command_address = da_command_address;
+        command.command_code = da_command_code;
+        command.ebx = virt_to_phys(buffer);
+        command.ecx = 0x42534931;
+
+        buffer->class = class;
+        buffer->select = select;
+
+        dcdbas_smi_request(&command);
+
+        return buffer;
+}
+
+/* Derived from information in DellWirelessCtl.cpp:
+   Class 17, select 11 is radio control. It returns an array of 32-bit values.
+
+   result[0]: return code
+   result[1]:
+     Bit 0:      Hardware switch supported
+     Bit 1:      Wifi locator supported
+     Bit 2:      Wifi is supported
+     Bit 3:      Bluetooth is supported
+     Bit 4:      WWAN is supported
+     Bit 5:      Wireless keyboard supported
+     Bits 6-7:   Reserved
+     Bit 8:      Wifi is installed
+     Bit 9:      Bluetooth is installed
+     Bit 10:     WWAN is installed
+     Bits 11-15: Reserved
+     Bit 16:     Hardware switch is on
+     Bit 17:     Wifi is blocked
+     Bit 18:     Bluetooth is blocked
+     Bit 19:     WWAN is blocked
+     Bits 20-31: Reserved
+   result[2]: NVRAM size in bytes
+   result[3]: NVRAM format version number
+*/
+
+static int dell_rfkill_set(int radio, enum rfkill_state state)
+{
+        struct calling_interface_buffer buffer;
+        int disable = (state == RFKILL_STATE_UNBLOCKED) ? 0 : 1;
+
+        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
+        buffer.input[0] = (1 | (radio<<8) | (disable << 16));
+        dell_send_request(&buffer, 17, 11);
+
+        return 0;
+}
+
+static int dell_wifi_set(void *data, enum rfkill_state state)
+{
+        return dell_rfkill_set(1, state);
+}
+
+static int dell_bluetooth_set(void *data, enum rfkill_state state)
+{
+        return dell_rfkill_set(2, state);
+}
+
+static int dell_wwan_set(void *data, enum rfkill_state state)
+{
+        return dell_rfkill_set(3, state);
+}
+
+static int dell_rfkill_get(int bit, enum rfkill_state *state)
+{
+        struct calling_interface_buffer buffer;
+        int status;
+        int new_state = RFKILL_STATE_HARD_BLOCKED;
+
+        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
+        dell_send_request(&buffer, 17, 11);
+        status = buffer.output[1];
+
+        if (status & (1<<16))
+                new_state = RFKILL_STATE_SOFT_BLOCKED;
+
+        if (status & (1<<bit))
+                *state = new_state;
+        else
+                *state = RFKILL_STATE_UNBLOCKED;
+
+        return 0;
+}
+
+static int dell_wifi_get(void *data, enum rfkill_state *state)
+{
+        return dell_rfkill_get(17, state);
+}
+
+static int dell_bluetooth_get(void *data, enum rfkill_state *state)
+{
+        return dell_rfkill_get(18, state);
+}
+
+static int dell_wwan_get(void *data, enum rfkill_state *state)
+{
+        return dell_rfkill_get(19, state);
+}
+
+static int dell_setup_rfkill(void)
+{
+        struct calling_interface_buffer buffer;
+        int status;
+        int ret;
+
+        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
+        dell_send_request(&buffer, 17, 11);
+        status = buffer.output[1];
+
+        if ((status & (1<<2|1<<8)) == (1<<2|1<<8)) {
+                wifi_rfkill = rfkill_allocate(NULL, RFKILL_TYPE_WLAN);
+                if (!wifi_rfkill)
+                        goto err_wifi;
+                wifi_rfkill->name = "dell-wifi";
+                wifi_rfkill->toggle_radio = dell_wifi_set;
+                wifi_rfkill->get_state = dell_wifi_get;
+                ret = rfkill_register(wifi_rfkill);
+                if (ret)
+                        goto err_wifi;
+        }
+
+        if ((status & (1<<3|1<<9)) == (1<<3|1<<9)) {
+                bluetooth_rfkill = rfkill_allocate(NULL, RFKILL_TYPE_BLUETOOTH);
+                if (!bluetooth_rfkill)
+                        goto err_bluetooth;
+                bluetooth_rfkill->name = "dell-bluetooth";
+                bluetooth_rfkill->toggle_radio = dell_bluetooth_set;
+                bluetooth_rfkill->get_state = dell_bluetooth_get;
+                ret = rfkill_register(bluetooth_rfkill);
+                if (ret)
+                        goto err_bluetooth;
+        }
+
+        if ((status & (1<<4|1<<10)) == (1<<4|1<<10)) {
+                wwan_rfkill = rfkill_allocate(NULL, RFKILL_TYPE_WWAN);
+                if (!wwan_rfkill)
+                        goto err_wwan;
+                wwan_rfkill->name = "dell-wwan";
+                wwan_rfkill->toggle_radio = dell_wwan_set;
+                wwan_rfkill->get_state = dell_wwan_get;
+                ret = rfkill_register(wwan_rfkill);
+                if (ret)
+                        goto err_wwan;
+        }
+
+        return 0;
+err_wwan:
+        if (wwan_rfkill)
+                rfkill_free(wwan_rfkill);
+        if (bluetooth_rfkill) {
+                rfkill_unregister(bluetooth_rfkill);
+                bluetooth_rfkill = NULL;
+        }
+err_bluetooth:
+        if (bluetooth_rfkill)
+                rfkill_free(bluetooth_rfkill);
+        if (wifi_rfkill) {
+                rfkill_unregister(wifi_rfkill);
+                wifi_rfkill = NULL;
+        }
+err_wifi:
+        if (wifi_rfkill)
+                rfkill_free(wifi_rfkill);
+
+        return ret;
+}
+
+static int dell_send_intensity(struct backlight_device *bd)
+{
+        struct calling_interface_buffer buffer;
+
+        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
+        buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
+        buffer.input[1] = bd->props.brightness;
+
+        if (buffer.input[0] == -1)
+                return -ENODEV;
+
+        if (power_supply_is_system_supplied() > 0)
+                dell_send_request(&buffer, 1, 2);
+        else
+                dell_send_request(&buffer, 1, 1);
+
+        return 0;
+}
+
+static int dell_get_intensity(struct backlight_device *bd)
+{
+        struct calling_interface_buffer buffer;
+
+        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
+        buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
+
+        if (buffer.input[0] == -1)
+                return -ENODEV;
+
+        if (power_supply_is_system_supplied() > 0)
+                dell_send_request(&buffer, 0, 2);
+        else
+                dell_send_request(&buffer, 0, 1);
+
+        return buffer.output[1];
+}
+
+static struct backlight_ops dell_ops = {
+        .get_brightness = dell_get_intensity,
+        .update_status  = dell_send_intensity,
+};
+
+static int __init dell_init(void)
+{
+        struct calling_interface_buffer buffer;
+        int max_intensity = 0;
+        int ret;
+
+        if (!dmi_check_system(dell_device_table))
+                return -ENODEV;
+
+        dmi_walk(find_tokens);
+
+        if (!da_tokens)  {
+                printk(KERN_INFO "dell-laptop: Unable to find dmi tokens\n");
+                return -ENODEV;
+        }
+
+        ret = dell_setup_rfkill();
+
+        if (ret) {
+                printk(KERN_WARNING "dell-laptop: Unable to setup rfkill\n");
+                goto out;
+        }
+
+#ifdef CONFIG_ACPI
+        /* In the event of an ACPI backlight being available, don't
+         * register the platform controller.
+         */
+        if (acpi_video_backlight_support())
+                return 0;
+#endif
+
+        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
+        buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
+
+        if (buffer.input[0] != -1) {
+                dell_send_request(&buffer, 0, 2);
+                max_intensity = buffer.output[3];
+        }
+
+        if (max_intensity) {
+                dell_backlight_device = backlight_device_register(
+                        "dell_backlight",
+                        NULL, NULL,
+                        &dell_ops);
+
+                if (IS_ERR(dell_backlight_device)) {
+                        ret = PTR_ERR(dell_backlight_device);
+                        dell_backlight_device = NULL;
+                        goto out;
+                }
+
+                dell_backlight_device->props.max_brightness = max_intensity;
+                dell_backlight_device->props.brightness =
+                        dell_get_intensity(dell_backlight_device);
+                backlight_update_status(dell_backlight_device);
+        }
+
+        return 0;
+out:
+        if (wifi_rfkill)
+                rfkill_unregister(wifi_rfkill);
+        if (bluetooth_rfkill)
+                rfkill_unregister(bluetooth_rfkill);
+        if (wwan_rfkill)
+                rfkill_unregister(wwan_rfkill);
+        kfree(da_tokens);
+        return ret;
+}
+
+static void __exit dell_exit(void)
+{
+        backlight_device_unregister(dell_backlight_device);
+        if (wifi_rfkill)
+                rfkill_unregister(wifi_rfkill);
+        if (bluetooth_rfkill)
+                rfkill_unregister(bluetooth_rfkill);
+        if (wwan_rfkill)
+                rfkill_unregister(wwan_rfkill);
+}
+
+module_init(dell_init);
+module_exit(dell_exit);
+
+MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
+MODULE_DESCRIPTION("Dell laptop driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("dmi:*svnDellInc.:*:ct8:*");