// SPDX-License-Identifier: GPL-2.0
/*
* 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 <[email protected]>
*/
#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/panic_notifier.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)
{
u16 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)
{
ktime_t delta_t, now;
while (1) {
now = ktime_get();
delta_t = ktime_sub(now, dcon->load_time);
if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
break;
mdelay(4);
}
}
static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
{
int err;
console_lock();
lock_fb_info(dcon->fbinfo);
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("%s to CPU\n", __func__);
/* 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);
dcon->load_time = ktime_get();
pr_info("The CPU has control\n");
break;
case DCON_SOURCE_DCON:
{
ktime_t delta_t;
pr_info("%s to DCON\n", __func__);
/* Clear DCONLOAD - this implies that the DCON is in control */
pdata->set_dconload(0);
dcon->load_time = ktime_get();
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 = ktime_sub(dcon->irq_time, dcon->load_time);
if (dcon->switched && ktime_to_ns(delta_t)
< NSEC_PER_MSEC * 20) {
pr_err("missed loading, retrying\n");
pdata->set_dconload(1);
mdelay(41);
pdata->set_dconload(0);
dcon->load_time = ktime_get();
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_work(&dcon->switch_source);
}
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;
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 = backlight_get_brightness(dev) & 0x0F;
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 = BACKLIGHT_POWER_ON,
};
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)
{
strscpy(info->type, "olpc_dcon", I2C_NAME_SIZE);
return 0;
}
static int dcon_probe(struct i2c_client *client)
{
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) {
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]);
platform_device_del(dcon_device);
edev:
platform_device_put(dcon_device);
dcon_device = NULL;
eirq:
free_irq(DCON_IRQ, dcon);
einit:
kfree(dcon);
return rc;
}
static void 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)
platform_device_unregister(dcon_device);
cancel_work_sync(&dcon->switch_source);
kfree(dcon);
}
#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;
dcon->irq_time = ktime_get();
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;
dcon->irq_time = ktime_get();
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_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)
{
/* XO-1.5 */
if (olpc_board_at_least(olpc_board(0xd0)))
pdata = &dcon_pdata_xo_1_5;
else
pdata = &dcon_pdata_xo_1;
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");
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