Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / staging / olpc_dcon / olpc_dcon.c
diff --git a/kernel/drivers/staging/olpc_dcon/olpc_dcon.c b/kernel/drivers/staging/olpc_dcon/olpc_dcon.c
new file mode 100644 (file)
index 0000000..d115f5c
--- /dev/null
@@ -0,0 +1,817 @@
+/*
+ * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
+ *
+ * Copyright © 2006-2007  Red Hat, Inc.
+ * Copyright © 2006-2007  Advanced Micro Devices, Inc.
+ * Copyright © 2009       VIA Technology, Inc.
+ * Copyright (c) 2010-2011  Andres Salomon <dilinger@queued.net>
+ *
+ * This program is free software.  You can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/fb.h>
+#include <linux/console.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/backlight.h>
+#include <linux/device.h>
+#include <linux/uaccess.h>
+#include <linux/ctype.h>
+#include <linux/reboot.h>
+#include <linux/olpc-ec.h>
+#include <asm/tsc.h>
+#include <asm/olpc.h>
+
+#include "olpc_dcon.h"
+
+/* Module definitions */
+
+static ushort resumeline = 898;
+module_param(resumeline, ushort, 0444);
+
+static struct dcon_platform_data *pdata;
+
+/* I2C structures */
+
+/* Platform devices */
+static struct platform_device *dcon_device;
+
+static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
+
+static s32 dcon_write(struct dcon_priv *dcon, u8 reg, u16 val)
+{
+       return i2c_smbus_write_word_data(dcon->client, reg, val);
+}
+
+static s32 dcon_read(struct dcon_priv *dcon, u8 reg)
+{
+       return i2c_smbus_read_word_data(dcon->client, reg);
+}
+
+/* ===== API functions - these are called by a variety of users ==== */
+
+static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
+{
+       uint16_t ver;
+       int rc = 0;
+
+       ver = dcon_read(dcon, DCON_REG_ID);
+       if ((ver >> 8) != 0xDC) {
+               pr_err("DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
+               rc = -ENXIO;
+               goto err;
+       }
+
+       if (is_init) {
+               pr_info("Discovered DCON version %x\n", ver & 0xFF);
+               rc = pdata->init(dcon);
+               if (rc != 0) {
+                       pr_err("Unable to init.\n");
+                       goto err;
+               }
+       }
+
+       if (ver < 0xdc02) {
+               dev_err(&dcon->client->dev,
+                               "DCON v1 is unsupported, giving up..\n");
+               rc = -ENODEV;
+               goto err;
+       }
+
+       /* SDRAM setup/hold time */
+       dcon_write(dcon, 0x3a, 0xc040);
+       dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000);  /* clear option bits */
+       dcon_write(dcon, DCON_REG_MEM_OPT_A,
+                               MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
+       dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
+
+       /* Colour swizzle, AA, no passthrough, backlight */
+       if (is_init) {
+               dcon->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
+                               MODE_CSWIZZLE | MODE_COL_AA;
+       }
+       dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
+
+
+       /* Set the scanline to interrupt on during resume */
+       dcon_write(dcon, DCON_REG_SCAN_INT, resumeline);
+
+err:
+       return rc;
+}
+
+/*
+ * The smbus doesn't always come back due to what is believed to be
+ * hardware (power rail) bugs.  For older models where this is known to
+ * occur, our solution is to attempt to wait for the bus to stabilize;
+ * if it doesn't happen, cut power to the dcon, repower it, and wait
+ * for the bus to stabilize.  Rinse, repeat until we have a working
+ * smbus.  For newer models, we simply BUG(); we want to know if this
+ * still happens despite the power fixes that have been made!
+ */
+static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
+{
+       unsigned long timeout;
+       u8 pm;
+       int x;
+
+power_up:
+       if (is_powered_down) {
+               pm = 1;
+               x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
+               if (x) {
+                       pr_warn("unable to force dcon to power up: %d!\n", x);
+                       return x;
+               }
+               usleep_range(10000, 11000);  /* we'll be conservative */
+       }
+
+       pdata->bus_stabilize_wiggle();
+
+       for (x = -1, timeout = 50; timeout && x < 0; timeout--) {
+               usleep_range(1000, 1100);
+               x = dcon_read(dcon, DCON_REG_ID);
+       }
+       if (x < 0) {
+               pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
+               BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
+               pm = 0;
+               olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
+               msleep(100);
+               is_powered_down = 1;
+               goto power_up;  /* argh, stupid hardware.. */
+       }
+
+       if (is_powered_down)
+               return dcon_hw_init(dcon, 0);
+       return 0;
+}
+
+static void dcon_set_backlight(struct dcon_priv *dcon, u8 level)
+{
+       dcon->bl_val = level;
+       dcon_write(dcon, DCON_REG_BRIGHT, dcon->bl_val);
+
+       /* Purposely turn off the backlight when we go to level 0 */
+       if (dcon->bl_val == 0) {
+               dcon->disp_mode &= ~MODE_BL_ENABLE;
+               dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
+       } else if (!(dcon->disp_mode & MODE_BL_ENABLE)) {
+               dcon->disp_mode |= MODE_BL_ENABLE;
+               dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
+       }
+}
+
+/* Set the output type to either color or mono */
+static int dcon_set_mono_mode(struct dcon_priv *dcon, bool enable_mono)
+{
+       if (dcon->mono == enable_mono)
+               return 0;
+
+       dcon->mono = enable_mono;
+
+       if (enable_mono) {
+               dcon->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
+               dcon->disp_mode |= MODE_MONO_LUMA;
+       } else {
+               dcon->disp_mode &= ~(MODE_MONO_LUMA);
+               dcon->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
+       }
+
+       dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode);
+       return 0;
+}
+
+/* For now, this will be really stupid - we need to address how
+ * DCONLOAD works in a sleep and account for it accordingly
+ */
+
+static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
+{
+       int x;
+
+       /* Turn off the backlight and put the DCON to sleep */
+
+       if (dcon->asleep == sleep)
+               return;
+
+       if (!olpc_board_at_least(olpc_board(0xc2)))
+               return;
+
+       if (sleep) {
+               u8 pm = 0;
+
+               x = olpc_ec_cmd(EC_DCON_POWER_MODE, &pm, 1, NULL, 0);
+               if (x)
+                       pr_warn("unable to force dcon to power down: %d!\n", x);
+               else
+                       dcon->asleep = sleep;
+       } else {
+               /* Only re-enable the backlight if the backlight value is set */
+               if (dcon->bl_val != 0)
+                       dcon->disp_mode |= MODE_BL_ENABLE;
+               x = dcon_bus_stabilize(dcon, 1);
+               if (x)
+                       pr_warn("unable to reinit dcon hardware: %d!\n", x);
+               else
+                       dcon->asleep = sleep;
+
+               /* Restore backlight */
+               dcon_set_backlight(dcon, dcon->bl_val);
+       }
+
+       /* We should turn off some stuff in the framebuffer - but what? */
+}
+
+/* the DCON seems to get confused if we change DCONLOAD too
+ * frequently -- i.e., approximately faster than frame time.
+ * normally we don't change it this fast, so in general we won't
+ * delay here.
+ */
+static void dcon_load_holdoff(struct dcon_priv *dcon)
+{
+       struct timespec delta_t, now;
+
+       while (1) {
+               getnstimeofday(&now);
+               delta_t = timespec_sub(now, dcon->load_time);
+               if (delta_t.tv_sec != 0 ||
+                       delta_t.tv_nsec > NSEC_PER_MSEC * 20) {
+                       break;
+               }
+               mdelay(4);
+       }
+}
+
+static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
+{
+       int err;
+
+       console_lock();
+       if (!lock_fb_info(dcon->fbinfo)) {
+               console_unlock();
+               dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
+               return false;
+       }
+
+       dcon->ignore_fb_events = true;
+       err = fb_blank(dcon->fbinfo,
+                       blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
+       dcon->ignore_fb_events = false;
+       unlock_fb_info(dcon->fbinfo);
+       console_unlock();
+
+       if (err) {
+               dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
+                               blank ? "" : "un");
+               return false;
+       }
+       return true;
+}
+
+/* Set the source of the display (CPU or DCON) */
+static void dcon_source_switch(struct work_struct *work)
+{
+       struct dcon_priv *dcon = container_of(work, struct dcon_priv,
+                       switch_source);
+       int source = dcon->pending_src;
+
+       if (dcon->curr_src == source)
+               return;
+
+       dcon_load_holdoff(dcon);
+
+       dcon->switched = false;
+
+       switch (source) {
+       case DCON_SOURCE_CPU:
+               pr_info("dcon_source_switch to CPU\n");
+               /* Enable the scanline interrupt bit */
+               if (dcon_write(dcon, DCON_REG_MODE,
+                               dcon->disp_mode | MODE_SCAN_INT))
+                       pr_err("couldn't enable scanline interrupt!\n");
+               else
+                       /* Wait up to one second for the scanline interrupt */
+                       wait_event_timeout(dcon->waitq, dcon->switched, HZ);
+
+               if (!dcon->switched)
+                       pr_err("Timeout entering CPU mode; expect a screen glitch.\n");
+
+               /* Turn off the scanline interrupt */
+               if (dcon_write(dcon, DCON_REG_MODE, dcon->disp_mode))
+                       pr_err("couldn't disable scanline interrupt!\n");
+
+               /*
+                * Ideally we'd like to disable interrupts here so that the
+                * fb unblanking and DCON turn on happen at a known time value;
+                * however, we can't do that right now with fb_blank
+                * messing with semaphores.
+                *
+                * For now, we just hope..
+                */
+               if (!dcon_blank_fb(dcon, false)) {
+                       pr_err("Failed to enter CPU mode\n");
+                       dcon->pending_src = DCON_SOURCE_DCON;
+                       return;
+               }
+
+               /* And turn off the DCON */
+               pdata->set_dconload(1);
+               getnstimeofday(&dcon->load_time);
+
+               pr_info("The CPU has control\n");
+               break;
+       case DCON_SOURCE_DCON:
+       {
+               struct timespec delta_t;
+
+               pr_info("dcon_source_switch to DCON\n");
+
+               /* Clear DCONLOAD - this implies that the DCON is in control */
+               pdata->set_dconload(0);
+               getnstimeofday(&dcon->load_time);
+
+               wait_event_timeout(dcon->waitq, dcon->switched, HZ/2);
+
+               if (!dcon->switched) {
+                       pr_err("Timeout entering DCON mode; expect a screen glitch.\n");
+               } else {
+                       /* sometimes the DCON doesn't follow its own rules,
+                        * and doesn't wait for two vsync pulses before
+                        * ack'ing the frame load with an IRQ.  the result
+                        * is that the display shows the *previously*
+                        * loaded frame.  we can detect this by looking at
+                        * the time between asserting DCONLOAD and the IRQ --
+                        * if it's less than 20msec, then the DCON couldn't
+                        * have seen two VSYNC pulses.  in that case we
+                        * deassert and reassert, and hope for the best.
+                        * see http://dev.laptop.org/ticket/9664
+                        */
+                       delta_t = timespec_sub(dcon->irq_time, dcon->load_time);
+                       if (dcon->switched && delta_t.tv_sec == 0 &&
+                                       delta_t.tv_nsec < NSEC_PER_MSEC * 20) {
+                               pr_err("missed loading, retrying\n");
+                               pdata->set_dconload(1);
+                               mdelay(41);
+                               pdata->set_dconload(0);
+                               getnstimeofday(&dcon->load_time);
+                               mdelay(41);
+                       }
+               }
+
+               dcon_blank_fb(dcon, true);
+               pr_info("The DCON has control\n");
+               break;
+       }
+       default:
+               BUG();
+       }
+
+       dcon->curr_src = source;
+}
+
+static void dcon_set_source(struct dcon_priv *dcon, int arg)
+{
+       if (dcon->pending_src == arg)
+               return;
+
+       dcon->pending_src = arg;
+
+       if (dcon->curr_src != arg)
+               schedule_work(&dcon->switch_source);
+}
+
+static void dcon_set_source_sync(struct dcon_priv *dcon, int arg)
+{
+       dcon_set_source(dcon, arg);
+       flush_scheduled_work();
+}
+
+static ssize_t dcon_mode_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       struct dcon_priv *dcon = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%4.4X\n", dcon->disp_mode);
+}
+
+static ssize_t dcon_sleep_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       struct dcon_priv *dcon = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%d\n", dcon->asleep);
+}
+
+static ssize_t dcon_freeze_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       struct dcon_priv *dcon = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%d\n", dcon->curr_src == DCON_SOURCE_DCON ? 1 : 0);
+}
+
+static ssize_t dcon_mono_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       struct dcon_priv *dcon = dev_get_drvdata(dev);
+
+       return sprintf(buf, "%d\n", dcon->mono);
+}
+
+static ssize_t dcon_resumeline_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "%d\n", resumeline);
+}
+
+static ssize_t dcon_mono_store(struct device *dev,
+       struct device_attribute *attr, const char *buf, size_t count)
+{
+       unsigned long enable_mono;
+       int rc;
+
+       rc = kstrtoul(buf, 10, &enable_mono);
+       if (rc)
+               return rc;
+
+       dcon_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
+
+       return count;
+}
+
+static ssize_t dcon_freeze_store(struct device *dev,
+       struct device_attribute *attr, const char *buf, size_t count)
+{
+       struct dcon_priv *dcon = dev_get_drvdata(dev);
+       unsigned long output;
+       int ret;
+
+       ret = kstrtoul(buf, 10, &output);
+       if (ret)
+               return ret;
+
+       pr_info("dcon_freeze_store: %lu\n", output);
+
+       switch (output) {
+       case 0:
+               dcon_set_source(dcon, DCON_SOURCE_CPU);
+               break;
+       case 1:
+               dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
+               break;
+       case 2:  /* normally unused */
+               dcon_set_source(dcon, DCON_SOURCE_DCON);
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return count;
+}
+
+static ssize_t dcon_resumeline_store(struct device *dev,
+       struct device_attribute *attr, const char *buf, size_t count)
+{
+       unsigned short rl;
+       int rc;
+
+       rc = kstrtou16(buf, 10, &rl);
+       if (rc)
+               return rc;
+
+       resumeline = rl;
+       dcon_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, resumeline);
+
+       return count;
+}
+
+static ssize_t dcon_sleep_store(struct device *dev,
+       struct device_attribute *attr, const char *buf, size_t count)
+{
+       unsigned long output;
+       int ret;
+
+       ret = kstrtoul(buf, 10, &output);
+       if (ret)
+               return ret;
+
+       dcon_sleep(dev_get_drvdata(dev), output ? true : false);
+       return count;
+}
+
+static struct device_attribute dcon_device_files[] = {
+       __ATTR(mode, 0444, dcon_mode_show, NULL),
+       __ATTR(sleep, 0644, dcon_sleep_show, dcon_sleep_store),
+       __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
+       __ATTR(monochrome, 0644, dcon_mono_show, dcon_mono_store),
+       __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
+};
+
+static int dcon_bl_update(struct backlight_device *dev)
+{
+       struct dcon_priv *dcon = bl_get_data(dev);
+       u8 level = dev->props.brightness & 0x0F;
+
+       if (dev->props.power != FB_BLANK_UNBLANK)
+               level = 0;
+
+       if (level != dcon->bl_val)
+               dcon_set_backlight(dcon, level);
+
+       /* power down the DCON when the screen is blanked */
+       if (!dcon->ignore_fb_events)
+               dcon_sleep(dcon, !!(dev->props.state & BL_CORE_FBBLANK));
+
+       return 0;
+}
+
+static int dcon_bl_get(struct backlight_device *dev)
+{
+       struct dcon_priv *dcon = bl_get_data(dev);
+
+       return dcon->bl_val;
+}
+
+static const struct backlight_ops dcon_bl_ops = {
+       .update_status = dcon_bl_update,
+       .get_brightness = dcon_bl_get,
+};
+
+static struct backlight_properties dcon_bl_props = {
+       .max_brightness = 15,
+       .type = BACKLIGHT_RAW,
+       .power = FB_BLANK_UNBLANK,
+};
+
+static int dcon_reboot_notify(struct notifier_block *nb,
+                             unsigned long foo, void *bar)
+{
+       struct dcon_priv *dcon = container_of(nb, struct dcon_priv, reboot_nb);
+
+       if (!dcon || !dcon->client)
+               return NOTIFY_DONE;
+
+       /* Turn off the DCON. Entirely. */
+       dcon_write(dcon, DCON_REG_MODE, 0x39);
+       dcon_write(dcon, DCON_REG_MODE, 0x32);
+       return NOTIFY_DONE;
+}
+
+static int unfreeze_on_panic(struct notifier_block *nb,
+                            unsigned long e, void *p)
+{
+       pdata->set_dconload(1);
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block dcon_panic_nb = {
+       .notifier_call = unfreeze_on_panic,
+};
+
+static int dcon_detect(struct i2c_client *client, struct i2c_board_info *info)
+{
+       strlcpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
+
+       return 0;
+}
+
+static int dcon_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+       struct dcon_priv *dcon;
+       int rc, i, j;
+
+       if (!pdata)
+               return -ENXIO;
+
+       dcon = kzalloc(sizeof(*dcon), GFP_KERNEL);
+       if (!dcon)
+               return -ENOMEM;
+
+       dcon->client = client;
+       init_waitqueue_head(&dcon->waitq);
+       INIT_WORK(&dcon->switch_source, dcon_source_switch);
+       dcon->reboot_nb.notifier_call = dcon_reboot_notify;
+       dcon->reboot_nb.priority = -1;
+
+       i2c_set_clientdata(client, dcon);
+
+       if (num_registered_fb < 1) {
+               dev_err(&client->dev, "DCON driver requires a registered fb\n");
+               rc = -EIO;
+               goto einit;
+       }
+       dcon->fbinfo = registered_fb[0];
+
+       rc = dcon_hw_init(dcon, 1);
+       if (rc)
+               goto einit;
+
+       /* Add the DCON device */
+
+       dcon_device = platform_device_alloc("dcon", -1);
+
+       if (dcon_device == NULL) {
+               pr_err("Unable to create the DCON device\n");
+               rc = -ENOMEM;
+               goto eirq;
+       }
+       rc = platform_device_add(dcon_device);
+       platform_set_drvdata(dcon_device, dcon);
+
+       if (rc) {
+               pr_err("Unable to add the DCON device\n");
+               goto edev;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(dcon_device_files); i++) {
+               rc = device_create_file(&dcon_device->dev,
+                                       &dcon_device_files[i]);
+               if (rc) {
+                       dev_err(&dcon_device->dev, "Cannot create sysfs file\n");
+                       goto ecreate;
+               }
+       }
+
+       dcon->bl_val = dcon_read(dcon, DCON_REG_BRIGHT) & 0x0F;
+
+       /* Add the backlight device for the DCON */
+       dcon_bl_props.brightness = dcon->bl_val;
+       dcon->bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
+               dcon, &dcon_bl_ops, &dcon_bl_props);
+       if (IS_ERR(dcon->bl_dev)) {
+               dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
+                               PTR_ERR(dcon->bl_dev));
+               dcon->bl_dev = NULL;
+       }
+
+       register_reboot_notifier(&dcon->reboot_nb);
+       atomic_notifier_chain_register(&panic_notifier_list, &dcon_panic_nb);
+
+       return 0;
+
+ ecreate:
+       for (j = 0; j < i; j++)
+               device_remove_file(&dcon_device->dev, &dcon_device_files[j]);
+ edev:
+       platform_device_unregister(dcon_device);
+       dcon_device = NULL;
+ eirq:
+       free_irq(DCON_IRQ, dcon);
+ einit:
+       kfree(dcon);
+       return rc;
+}
+
+static int dcon_remove(struct i2c_client *client)
+{
+       struct dcon_priv *dcon = i2c_get_clientdata(client);
+
+       unregister_reboot_notifier(&dcon->reboot_nb);
+       atomic_notifier_chain_unregister(&panic_notifier_list, &dcon_panic_nb);
+
+       free_irq(DCON_IRQ, dcon);
+
+       backlight_device_unregister(dcon->bl_dev);
+
+       if (dcon_device != NULL)
+               platform_device_unregister(dcon_device);
+       cancel_work_sync(&dcon->switch_source);
+
+       kfree(dcon);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM
+static int dcon_suspend(struct device *dev)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct dcon_priv *dcon = i2c_get_clientdata(client);
+
+       if (!dcon->asleep) {
+               /* Set up the DCON to have the source */
+               dcon_set_source_sync(dcon, DCON_SOURCE_DCON);
+       }
+
+       return 0;
+}
+
+static int dcon_resume(struct device *dev)
+{
+       struct i2c_client *client = to_i2c_client(dev);
+       struct dcon_priv *dcon = i2c_get_clientdata(client);
+
+       if (!dcon->asleep) {
+               dcon_bus_stabilize(dcon, 0);
+               dcon_set_source(dcon, DCON_SOURCE_CPU);
+       }
+
+       return 0;
+}
+
+#else
+
+#define dcon_suspend NULL
+#define dcon_resume NULL
+
+#endif /* CONFIG_PM */
+
+
+irqreturn_t dcon_interrupt(int irq, void *id)
+{
+       struct dcon_priv *dcon = id;
+       u8 status;
+
+       if (pdata->read_status(&status))
+               return IRQ_NONE;
+
+       switch (status & 3) {
+       case 3:
+               pr_debug("DCONLOAD_MISSED interrupt\n");
+               break;
+
+       case 2: /* switch to DCON mode */
+       case 1: /* switch to CPU mode */
+               dcon->switched = true;
+               getnstimeofday(&dcon->irq_time);
+               wake_up(&dcon->waitq);
+               break;
+
+       case 0:
+               /* workaround resume case:  the DCON (on 1.5) doesn't
+                * ever assert status 0x01 when switching to CPU mode
+                * during resume.  this is because DCONLOAD is de-asserted
+                * _immediately_ upon exiting S3, so the actual release
+                * of the DCON happened long before this point.
+                * see http://dev.laptop.org/ticket/9869
+                */
+               if (dcon->curr_src != dcon->pending_src && !dcon->switched) {
+                       dcon->switched = true;
+                       getnstimeofday(&dcon->irq_time);
+                       wake_up(&dcon->waitq);
+                       pr_debug("switching w/ status 0/0\n");
+               } else {
+                       pr_debug("scanline interrupt w/CPU\n");
+               }
+       }
+
+       return IRQ_HANDLED;
+}
+
+static const struct dev_pm_ops dcon_pm_ops = {
+       .suspend = dcon_suspend,
+       .resume = dcon_resume,
+};
+
+static const struct i2c_device_id dcon_idtable[] = {
+       { "olpc_dcon",  0 },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, dcon_idtable);
+
+static struct i2c_driver dcon_driver = {
+       .driver = {
+               .name   = "olpc_dcon",
+               .pm = &dcon_pm_ops,
+       },
+       .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
+       .id_table = dcon_idtable,
+       .probe = dcon_probe,
+       .remove = dcon_remove,
+       .detect = dcon_detect,
+       .address_list = normal_i2c,
+};
+
+static int __init olpc_dcon_init(void)
+{
+#ifdef CONFIG_FB_OLPC_DCON_1_5
+       /* XO-1.5 */
+       if (olpc_board_at_least(olpc_board(0xd0)))
+               pdata = &dcon_pdata_xo_1_5;
+#endif
+#ifdef CONFIG_FB_OLPC_DCON_1
+       if (!pdata)
+               pdata = &dcon_pdata_xo_1;
+#endif
+
+       return i2c_add_driver(&dcon_driver);
+}
+
+static void __exit olpc_dcon_exit(void)
+{
+       i2c_del_driver(&dcon_driver);
+}
+
+module_init(olpc_dcon_init);
+module_exit(olpc_dcon_exit);
+
+MODULE_LICENSE("GPL");