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Diffstat (limited to 'target/linux/olpc/files/drivers/video/olpc_dcon.c')
-rw-r--r--target/linux/olpc/files/drivers/video/olpc_dcon.c824
1 files changed, 824 insertions, 0 deletions
diff --git a/target/linux/olpc/files/drivers/video/olpc_dcon.c b/target/linux/olpc/files/drivers/video/olpc_dcon.c
new file mode 100644
index 0000000000..d4ef138676
--- /dev/null
+++ b/target/linux/olpc/files/drivers/video/olpc_dcon.c
@@ -0,0 +1,824 @@
+/*
+ * Mainly by David Woodhouse, somewhat modified by Jordan Crouse
+ *
+ * Copyright © 2006-2007 Red Hat, Inc.
+ * Copyright © 2006-2007 Advanced Micro Devices, Inc.
+ *
+ * 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.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/fb.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/i2c-id.h>
+#include <linux/pci.h>
+#include <linux/vt_kern.h>
+#include <linux/pci_ids.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/backlight.h>
+#include <linux/device.h>
+#include <asm/uaccess.h>
+#include <linux/ctype.h>
+#include <linux/reboot.h>
+#include <asm/tsc.h>
+#include <asm/olpc.h>
+
+#include "olpc_dcon.h"
+
+/* Module definitions */
+
+static int resumeline = 898;
+module_param(resumeline, int, 0444);
+
+static int noinit;
+module_param(noinit, int, 0444);
+
+/* Default off since it doesn't work on DCON ASIC in B-test OLPC board */
+static int useaa = 1;
+module_param(useaa, int, 0444);
+
+/* I2C structures */
+
+static struct i2c_driver dcon_driver;
+static struct i2c_client *dcon_client;
+
+/* Platform devices */
+static struct platform_device *dcon_device;
+
+/* Backlight device */
+static struct backlight_device *dcon_bl_dev;
+
+/* Base address of the GPIO registers */
+static unsigned long gpio_base;
+
+static struct fb_info *fbinfo;
+
+/* Current source, initialized at probe time */
+static int dcon_source;
+
+/* Desired source */
+static int dcon_pending;
+
+/* Current output type */
+static int dcon_output = DCON_OUTPUT_COLOR;
+
+/* Current sleep status (not yet implemented) */
+static int dcon_sleep_val = DCON_ACTIVE;
+
+/* Shadow register for the DCON_REG_MODE register */
+static unsigned short dcon_disp_mode;
+
+/* Variables used during switches */
+static int dcon_switched;
+
+static DECLARE_WAIT_QUEUE_HEAD(dcon_wait_queue);
+
+static unsigned short normal_i2c[] = { 0x0D, I2C_CLIENT_END };
+I2C_CLIENT_INSMOD;
+
+#define dcon_write(reg,val) i2c_smbus_write_word_data(dcon_client,reg,val)
+#define dcon_read(reg) i2c_smbus_read_word_data(dcon_client,reg)
+
+/* The current backlight value - this saves us some smbus traffic */
+static int bl_val = -1;
+
+/* ===== API functions - these are called by a variety of users ==== */
+
+/* Backlight notes - turning off the backlight enable bit in the DCON
+ * doesn't save us any power over just pushing the BL to zero, so we
+ * don't use that bit in this code.
+ */
+
+static int dcon_get_backlight(void)
+{
+ if (dcon_client == NULL)
+ return 0;
+
+ if (bl_val == -1)
+ bl_val = dcon_read(DCON_REG_BRIGHT) & 0x0F;
+
+ return bl_val;
+}
+
+static void dcon_set_backlight(int level)
+{
+ if (dcon_client == NULL)
+ return;
+
+ if (bl_val == (level & 0x0F))
+ return;
+
+ bl_val = level & 0x0F;
+ dcon_write(DCON_REG_BRIGHT, bl_val);
+
+ /* Purposely turn off the backlight when we go to level 0 */
+
+ if (bl_val == 0) {
+ dcon_disp_mode &= ~MODE_BL_ENABLE;
+ dcon_write(DCON_REG_MODE, dcon_disp_mode);
+ }
+ else if (!(dcon_disp_mode & MODE_BL_ENABLE)) {
+ dcon_disp_mode |= MODE_BL_ENABLE;
+ dcon_write(DCON_REG_MODE, dcon_disp_mode);
+ }
+}
+
+/* Set the output type to either color or mono */
+
+static int dcon_set_output(int arg)
+{
+ if (dcon_output == arg)
+ return 0;
+
+ dcon_output = arg;
+
+ if (arg == DCON_OUTPUT_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;
+ if (useaa)
+ dcon_disp_mode |= MODE_COL_AA;
+ }
+
+ dcon_write(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(int state)
+{
+ /* Turn off the backlight and put the DCON to sleep */
+
+ if (state == dcon_sleep_val)
+ return;
+
+ if (state == DCON_SLEEP) {
+ dcon_disp_mode &= ~MODE_BL_ENABLE;
+ dcon_disp_mode |= MODE_SLEEP;
+ }
+ else {
+ /* Only re-enable the backlight if the backlight value is set */
+
+ if (bl_val != 0)
+ dcon_disp_mode |= MODE_BL_ENABLE;
+
+ dcon_disp_mode &= ~MODE_SLEEP;
+ }
+
+ dcon_sleep_val = state;
+ dcon_write(DCON_REG_MODE, dcon_disp_mode);
+
+ /* We should turn off some stuff in the framebuffer - but what? */
+}
+
+/* Set the source of the display (CPU or DCON) */
+
+static void dcon_source_switch(struct work_struct *work)
+{
+ DECLARE_WAITQUEUE(wait, current);
+ int source = dcon_pending;
+
+ if (dcon_source == source)
+ return;
+
+ dcon_switched = 0;
+
+ switch (source) {
+ case DCON_SOURCE_CPU:
+
+ /* Enable the scanline interrupt bit */
+ if (dcon_write(DCON_REG_MODE, dcon_disp_mode | MODE_SCAN_INT))
+ printk(KERN_ERR "olpc-dcon: couldn't enable scanline interrupt!\n");
+ else {
+ /* Wait up to one second for the scanline interrupt */
+ wait_event_timeout(dcon_wait_queue, dcon_switched == 1, HZ);
+ }
+
+ if (!dcon_switched)
+ printk(KERN_ERR "olpc-dcon: Timeout entering CPU mode; expect a screen glitch.\n");
+
+ /*
+ * Ideally we'd like to disable interrupts here so that the
+ * fb_powerup and DCON turn on happen at a known time value;
+ * however, we can't do that right now with fb_set_suspend
+ * messing with semaphores.
+ *
+ * For now, we just hope..
+ */
+ if (fb_powerup(fbinfo)) {
+ printk(KERN_ERR "olpc-dcon: Failed to enter CPU mode\n");
+ dcon_pending = DCON_SOURCE_DCON;
+ return;
+ }
+
+ /* And turn off the DCON */
+ outl(1<<11, gpio_base + GPIOx_OUT_VAL);
+
+ /* Turn off the scanline interrupt */
+ if (dcon_write(DCON_REG_MODE, dcon_disp_mode))
+ printk(KERN_ERR "olpc-dcon: couldn't disable scanline interrupt!\n");
+
+ printk(KERN_INFO "olpc-dcon: The CPU has control\n");
+ break;
+ case DCON_SOURCE_DCON:
+ {
+ int t;
+
+ add_wait_queue(&dcon_wait_queue, &wait);
+ set_current_state(TASK_UNINTERRUPTIBLE);
+
+ /* Clear GPIO11 (DCONLOAD) - this implies that the DCON is in
+ control */
+
+ outl(1 << (11 + 16), gpio_base + GPIOx_OUT_VAL);
+
+ t = schedule_timeout(HZ/2);
+ remove_wait_queue(&dcon_wait_queue, &wait);
+ set_current_state(TASK_RUNNING);
+
+ if (!dcon_switched)
+ printk(KERN_ERR "olpc-dcon: Timeout entering DCON mode; expect a screen glitch.\n");
+
+ /* Turn off the graphics engine completely */
+ fb_powerdown(fbinfo);
+
+ printk(KERN_INFO "olpc-dcon: The DCON has control\n");
+ break;
+ }
+ default:
+ BUG();
+ }
+
+ dcon_source = source;
+}
+
+static DECLARE_WORK(dcon_work, dcon_source_switch);
+
+static int dcon_set_source(int arg)
+{
+ if (arg != DCON_SOURCE_CPU && arg != DCON_SOURCE_DCON)
+ return -EINVAL;
+
+ if (dcon_pending == arg)
+ return 0;
+
+ dcon_pending = arg;
+ if ((dcon_source != arg) && !work_pending(&dcon_work))
+ schedule_work(&dcon_work);
+
+ return 0;
+}
+
+static int dcon_set_source_sync(int arg)
+{
+ int ret = dcon_set_source(arg);
+ if (!ret)
+ flush_scheduled_work();
+ return ret;
+}
+
+static int dconbl_set(struct backlight_device *dev) {
+
+ int level = dev->props.brightness;
+
+ if (dev->props.power != FB_BLANK_UNBLANK)
+ level = 0;
+
+ dcon_set_backlight(level);
+ return 0;
+}
+
+static int dconbl_get(struct backlight_device *dev) {
+ return dcon_get_backlight();
+}
+
+static ssize_t dcon_mode_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%4.4X\n", dcon_disp_mode);
+}
+
+static ssize_t dcon_sleep_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", dcon_sleep_val);
+}
+
+static ssize_t /* __deprecated */ dcon_source_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ printk(KERN_WARNING "olpc-dcon: using deprecated sysfs 'source' interface; use 'freeze' instead!\n");
+ return sprintf(buf, "%d\n", dcon_source);
+}
+
+static ssize_t dcon_freeze_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", dcon_source == DCON_SOURCE_DCON ? 1 : 0);
+}
+
+static ssize_t dcon_output_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", dcon_output);
+}
+
+static ssize_t dcon_resumeline_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", resumeline);
+}
+
+static int _strtoul(const char *buf, int len, unsigned int *val)
+{
+
+ char *endp;
+ unsigned int output = simple_strtoul(buf, &endp, 0);
+ int size = endp - buf;
+
+ if (*endp && isspace(*endp))
+ size++;
+
+ if (size != len)
+ return -EINVAL;
+
+ *val = output;
+ return 0;
+}
+
+static ssize_t dcon_output_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int output;
+ int rc = -EINVAL;
+
+ if (_strtoul(buf, count, &output))
+ return -EINVAL;
+
+ if (output == DCON_OUTPUT_COLOR || output == DCON_OUTPUT_MONO) {
+ dcon_set_output(output);
+ rc = count;
+ }
+
+ return rc;
+}
+
+static ssize_t /* __deprecated */ dcon_source_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int output;
+ int rc = -EINVAL;
+
+ printk(KERN_WARNING "olpc-dcon: using deprecated sysfs 'source' interface; use 'freeze' instead!\n");
+ if (_strtoul(buf, count, &output))
+ return -EINVAL;
+
+ dcon_set_source(output);
+ rc = count;
+
+ return rc;
+}
+
+static ssize_t dcon_freeze_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int output;
+ int rc = -EINVAL;
+
+ if (_strtoul(buf, count, &output))
+ return rc;
+
+ dcon_set_source(output ? DCON_SOURCE_DCON : DCON_SOURCE_CPU);
+ rc = count;
+
+ return rc;
+}
+
+static ssize_t dcon_resumeline_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int rl;
+ int rc = -EINVAL;
+
+ if (_strtoul(buf, count, &rl))
+ return rc;
+
+ resumeline = rl;
+ dcon_write(DCON_REG_SCAN_INT, resumeline);
+ rc = count;
+
+ return rc;
+}
+
+static ssize_t dcon_sleep_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int output;
+
+ if (_strtoul(buf, count, &output))
+ return -EINVAL;
+
+ dcon_sleep(output ? DCON_SLEEP : DCON_ACTIVE);
+ 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(source, 0644, dcon_source_show, dcon_source_store),
+ __ATTR(freeze, 0644, dcon_freeze_show, dcon_freeze_store),
+ __ATTR(output, 0644, dcon_output_show, dcon_output_store),
+ __ATTR(resumeline, 0644, dcon_resumeline_show, dcon_resumeline_store),
+};
+
+static struct backlight_ops dcon_bl_ops = {
+ .get_brightness = dconbl_get,
+ .update_status = dconbl_set
+};
+
+/* List of GPIOs that we care about:
+ (in) GPIO12 -- DCONBLNK
+ (in) GPIO[56] -- DCONSTAT[01]
+ (out) GPIO11 -- DCONLOAD
+*/
+
+#define IN_GPIOS ((1<<5) | (1<<6) | (1<<7) | (1<<12))
+#define OUT_GPIOS (1<<11)
+
+static irqreturn_t dcon_interrupt(int, void *);
+
+static int dcon_request_irq(void)
+{
+ unsigned long lo, hi;
+ unsigned char lob;
+
+ rdmsr(MSR_LBAR_GPIO, lo, hi);
+
+ /* Check the mask and whether GPIO is enabled (sanity check) */
+ if (hi != 0x0000f001) {
+ printk(KERN_ERR "GPIO not enabled -- cannot use DCON\n");
+ return -ENODEV;
+ }
+
+ /* Mask off the IO base address */
+ gpio_base = lo & 0x0000ff00;
+
+ /* Turn off the event enable for GPIO7 just to be safe */
+ outl(1 << (16+7), gpio_base + GPIOx_EVNT_EN);
+
+ /* Set the directions for the GPIO pins */
+ outl(OUT_GPIOS | (IN_GPIOS << 16), gpio_base + GPIOx_OUT_EN);
+ outl(IN_GPIOS | (OUT_GPIOS << 16), gpio_base + GPIOx_IN_EN);
+
+ /* Set up the interrupt mappings */
+
+ /* Set the IRQ to pair 2 */
+ geode_gpio_event_irq(OLPC_GPIO_DCON_IRQ, 2);
+
+ /* Enable group 2 to trigger the DCON interrupt */
+ geode_gpio_set_irq(2, DCON_IRQ);
+
+ /* Select edge level for interrupt (in PIC) */
+
+ lob = inb(0x4d0);
+ lob &= ~(1 << DCON_IRQ);
+ outb(lob, 0x4d0);
+
+ /* Register the interupt handler */
+ if (request_irq(DCON_IRQ, &dcon_interrupt, 0, "DCON", &dcon_driver))
+ return -EIO;
+
+ /* Clear INV_EN for GPIO7 (DCONIRQ) */
+ outl((1<<(16+7)), gpio_base + GPIOx_INV_EN);
+
+ /* Enable filter for GPIO12 (DCONBLANK) */
+ outl(1<<(12), gpio_base + GPIOx_IN_FLTR_EN);
+
+ /* Disable filter for GPIO7 */
+ outl(1<<(16+7), gpio_base + GPIOx_IN_FLTR_EN);
+
+ /* Disable event counter for GPIO7 (DCONIRQ) and GPIO12 (DCONBLANK) */
+
+ outl(1<<(16+7), gpio_base + GPIOx_EVNTCNT_EN);
+ outl(1<<(16+12), gpio_base + GPIOx_EVNTCNT_EN);
+
+ /* Add GPIO12 to the Filter Event Pair #7 */
+ outb(12, gpio_base + GPIO_FE7_SEL);
+
+ /* Turn off negative Edge Enable for GPIO12 */
+ outl(1<<(16+12), gpio_base + GPIOx_NEGEDGE_EN);
+
+ /* Enable negative Edge Enable for GPIO7 */
+ outl(1<<7, gpio_base + GPIOx_NEGEDGE_EN);
+
+ /* Zero the filter amount for Filter Event Pair #7 */
+ outw(0, gpio_base + GPIO_FLT7_AMNT);
+
+ /* Clear the negative edge status for GPIO7 and GPIO12 */
+ outl((1<<7) | (1<<12), gpio_base+0x4c);
+
+ /* FIXME: Clear the posiitive status as well, just to be sure */
+ outl((1<<7) | (1<<12), gpio_base+0x48);
+
+ /* Enable events for GPIO7 (DCONIRQ) and GPIO12 (DCONBLANK) */
+ outl((1<<(7))|(1<<12), gpio_base + GPIOx_EVNT_EN);
+
+ /* Determine the current state by reading the GPIO bit */
+ /* Earlier stages of the boot process have established the state */
+ dcon_source = inl(gpio_base + GPIOx_OUT_VAL) & (1<<11)
+ ? DCON_SOURCE_CPU
+ : DCON_SOURCE_DCON;
+ dcon_pending = dcon_source;
+
+ return 0;
+}
+
+static int dcon_reboot_notify(struct notifier_block *nb, unsigned long foo, void *bar)
+{
+ if (dcon_client == NULL)
+ return 0;
+
+ /* Turn off the DCON. Entirely. */
+ dcon_write(DCON_REG_MODE, 0x39);
+ dcon_write(DCON_REG_MODE, 0x32);
+ return 0;
+}
+
+static int dcon_conswitch_notify(struct notifier_block *nb,
+ unsigned long mode, void *dummy)
+{
+ if (mode == CONSOLE_EVENT_SWITCH_TEXT)
+ dcon_sleep(DCON_ACTIVE);
+
+ return 0;
+}
+
+static struct notifier_block dcon_nb = {
+ .notifier_call = dcon_reboot_notify,
+ .priority = -1,
+};
+
+static struct notifier_block dcon_console_nb = {
+ .notifier_call = dcon_conswitch_notify,
+ .priority = -1,
+};
+
+static int dcon_probe(struct i2c_adapter *adap, int addr, int kind)
+{
+ struct i2c_client *client;
+ uint16_t ver;
+ int rc, i;
+
+ if (!olpc_has_dcon()) {
+ printk("olpc-dcon: No DCON is attached.\n");
+ return -ENODEV;
+ }
+
+ if (num_registered_fb >= 1)
+ fbinfo = registered_fb[0];
+
+ if (adap->id != I2C_HW_SMBUS_SCX200) {
+ printk(KERN_ERR "olpc-dcon: Invalid I2C bus (%d not %d)\n",
+ adap->id, I2C_HW_SMBUS_SCX200);
+ return -ENXIO;
+ }
+
+ client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
+ if (client == NULL)
+ return -ENOMEM;
+
+ strncpy(client->name, "OLPC-DCON", I2C_NAME_SIZE);
+ client->addr = addr;
+ client->adapter = adap;
+ client->driver = &dcon_driver;
+
+ if ((rc = i2c_attach_client(client)) != 0) {
+ printk(KERN_ERR "olpc-dcon: Unable to attach the I2C client.\n");
+ goto eclient;
+ }
+
+ ver = i2c_smbus_read_word_data(client, DCON_REG_ID);
+
+ if ((ver >> 8) != 0xDC) {
+ printk(KERN_ERR "olpc-dcon: DCON ID not 0xDCxx: 0x%04x instead.\n", ver);
+ rc = -ENXIO;
+ goto ei2c;
+ }
+
+ if ((rc = dcon_request_irq())) {
+ printk(KERN_ERR "olpc-dcon: Unable to grab IRQ.\n");
+ goto ei2c;
+ }
+
+ if (ver < 0xdc02 && !noinit) {
+ /* Initialize the DCON registers */
+
+ /* Start with work-arounds for DCON ASIC */
+ i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
+ i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
+ i2c_smbus_write_word_data(client, 0x4b, 0x00cc);
+ i2c_smbus_write_word_data(client, 0x0b, 0x007a);
+ i2c_smbus_write_word_data(client, 0x36, 0x025c);
+ i2c_smbus_write_word_data(client, 0x37, 0x025e);
+
+ /* Initialise SDRAM */
+
+ i2c_smbus_write_word_data(client, 0x3b, 0x002b);
+ i2c_smbus_write_word_data(client, 0x41, 0x0101);
+ i2c_smbus_write_word_data(client, 0x42, 0x0101);
+ }
+
+ /* Colour swizzle, AA, no passthrough, backlight */
+
+ dcon_disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE | MODE_CSWIZZLE;
+ if (useaa)
+ dcon_disp_mode |= MODE_COL_AA;
+ i2c_smbus_write_word_data(client, DCON_REG_MODE, dcon_disp_mode);
+
+
+ /* Set the scanline to interrupt on during resume */
+
+ i2c_smbus_write_word_data(client, DCON_REG_SCAN_INT, resumeline);
+
+ /* Add the DCON device */
+
+ dcon_device = platform_device_alloc("dcon", -1);
+
+ if (dcon_device == NULL) {
+ printk(KERN_ERR "dcon: Unable to create the DCON device\n");
+ rc = -ENOMEM;
+ goto eirq;
+ }
+
+ if ((rc = platform_device_add(dcon_device))) {
+ printk(KERN_ERR "dcon: Unable to add the DCON device\n");
+ goto edev;
+ }
+
+ for(i = 0; i < ARRAY_SIZE(dcon_device_files); i++)
+ device_create_file(&dcon_device->dev, &dcon_device_files[i]);
+
+ /* Add the backlight device for the DCON */
+
+ dcon_client = client;
+
+ dcon_bl_dev = backlight_device_register("dcon-bl", &dcon_device->dev,
+ NULL, &dcon_bl_ops);
+
+ if (IS_ERR(dcon_bl_dev)) {
+ printk(KERN_INFO "Could not register the backlight device for the DCON (%ld)\n", PTR_ERR(dcon_bl_dev));
+ dcon_bl_dev = NULL;
+ }
+ else {
+ dcon_bl_dev->props.max_brightness = 15;
+ dcon_bl_dev->props.power = FB_BLANK_UNBLANK;
+ dcon_bl_dev->props.brightness = dcon_get_backlight();
+
+ backlight_update_status(dcon_bl_dev);
+ }
+
+ register_reboot_notifier(&dcon_nb);
+ console_event_register(&dcon_console_nb);
+
+ printk(KERN_INFO "olpc-dcon: Discovered DCON version %x\n", ver & 0xFF);
+
+ return 0;
+
+ edev:
+ platform_device_unregister(dcon_device);
+ dcon_device = NULL;
+ eirq:
+ free_irq(DCON_IRQ, &dcon_driver);
+ ei2c:
+ i2c_detach_client(client);
+ eclient:
+ kfree(client);
+
+ return rc;
+}
+
+static int dcon_attach(struct i2c_adapter *adap)
+{
+ int ret;
+
+ ret = i2c_probe(adap, &addr_data, dcon_probe);
+
+ if (dcon_client == NULL)
+ printk(KERN_ERR "olpc-dcon: No DCON found on SMBus\n");
+
+ return ret;
+}
+
+static int dcon_detach(struct i2c_client *client)
+{
+ int rc;
+ dcon_client = NULL;
+
+ unregister_reboot_notifier(&dcon_nb);
+ console_event_unregister(&dcon_console_nb);
+
+ free_irq(DCON_IRQ, &dcon_driver);
+
+ if ((rc = i2c_detach_client(client)) == 0)
+ kfree(i2c_get_clientdata(client));
+
+ if (dcon_bl_dev != NULL)
+ backlight_device_unregister(dcon_bl_dev);
+
+ if (dcon_device != NULL)
+ platform_device_unregister(dcon_device);
+ cancel_work_sync(&dcon_work);
+
+ return rc;
+}
+
+
+#ifdef CONFIG_PM
+static int dcon_suspend(struct i2c_client *client, pm_message_t state)
+{
+ if (dcon_sleep_val != DCON_ACTIVE)
+ return 0;
+
+ /* Set up the DCON to have the source */
+ return dcon_set_source_sync(DCON_SOURCE_DCON);
+}
+
+static int dcon_resume(struct i2c_client *client)
+{
+ int x;
+ if (dcon_sleep_val != DCON_ACTIVE)
+ return 0;
+
+ /* HACK: ensure the bus is stable */
+ do {
+ x = dcon_read(DCON_REG_ID);
+ } while (x < 0);
+
+ return dcon_set_source(DCON_SOURCE_CPU);
+}
+
+#endif
+
+static irqreturn_t dcon_interrupt(int irq, void *id)
+{
+ int status = inl(gpio_base + GPIOx_READ_BACK) >> 5;
+
+ /* Clear the negative edge status for GPIO7 */
+ outl(1 << 7, gpio_base + GPIOx_NEGEDGE_STS);
+
+ switch (status & 3) {
+ case 3:
+ printk(KERN_DEBUG "olpc-dcon: DCONLOAD_MISSED interrupt\n");
+ break;
+ case 2: /* switch to DCON mode */
+ case 1: /* switch to CPU mode */
+ dcon_switched = 1;
+ wake_up(&dcon_wait_queue);
+ break;
+ case 0:
+ printk(KERN_DEBUG "olpc-dcon: scanline interrupt w/CPU\n");
+ }
+
+ return IRQ_HANDLED;
+}
+
+static struct i2c_driver dcon_driver = {
+ .driver = {
+ .name = "OLPC-DCON",
+ },
+ .id = I2C_DRIVERID_DCON,
+ .attach_adapter = dcon_attach,
+ .detach_client = dcon_detach,
+#ifdef CONFIG_PM
+ .suspend = dcon_suspend,
+ .resume = dcon_resume,
+#endif
+};
+
+
+static int __init olpc_dcon_init(void)
+{
+ i2c_add_driver(&dcon_driver);
+ return 0;
+}
+
+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");