[PATCH 2/2] misc: hx8837: add a HiMax HX8837 display controller driver

From: Lubomir Rintel
Date: Tue Sep 18 2018 - 16:44:27 EST

HiMax HX8837 is a display controller used on OLPC platforms.
It controlls backlight and is able to capture and freeze a frame when
the LCD controller (and the rest of the plaform) is powered off.

This driver is based on the same code as drivers/staging/olpc_dcon.
I modernized it to use managed GPIO, device-tree bindings, sysfs
attribtue groups, essentially fixing the staging driver's TODO.

Why I am not removing the staging driver now is because I've hobbled off
some functionality too (with an intent to bring add it back eventually):

* I've removed parts that talk directly to the OLPC EC to turn off/on
the power. My platform (OLPC 1.75) doesn't have an EC driver yet
(in progress!), and perhaps there's a more sensible API that should be
used (regulator? clock?).

* I couldn't test it with XO 1 and XO 1.5, because I don't have the
hardware. I think I'll be able to get a XO 1 laptop soonish, which
will make testing easier. I guess both platforms are DT-based and
could use the same bindings.

What is there is the backlight control and the sysfs attributes to
control the freeze/unfreeze..

I've also renamed the driver to use the actual chip name instead of the
original name that I found too generic. This way the staging driver can
be used on XO 1 and XO 1.5, while my XO 1.75 can utilize this one.

Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
---
drivers/misc/Kconfig | 16 +
drivers/misc/Makefile | 1 +
drivers/misc/hx8837.c | 749 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 766 insertions(+)
create mode 100644 drivers/misc/hx8837.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 3726eacdf65d..3eb6df0ea0a4 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -513,6 +513,22 @@ config MISC_RTSX
tristate
default MISC_RTSX_PCI || MISC_RTSX_USB

+config HX8837_DCON
+ tristate "HiMax HX8837 Display Controller on OLPC"
+ depends on I2C
+ depends on BACKLIGHT_LCD_SUPPORT
+ select BACKLIGHT_CLASS_DEVICE
+ help
+ In order to support very low power operation, the OLPC XO laptop uses a
+ secondary Display Controller, or DCON. This secondary controller
+ is present in the video pipeline between the primary display
+ controller (integrate into the processor or chipset) and the LCD
+ panel. It allows the main processor/display controller to be
+ completely powered off while still retaining an image on the display.
+ This controller is only available on OLPC platforms.
+
+ Unless you have an OLPC XO laptop, you will want to say N.
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index af22bbc3d00c..33689ae496b4 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -58,3 +58,4 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
obj-$(CONFIG_PCI_ENDPOINT_TEST) += pci_endpoint_test.o
obj-$(CONFIG_OCXL) += ocxl/
obj-$(CONFIG_MISC_RTSX) += cardreader/
+obj-$(CONFIG_HX8837_DCON) += hx8837.o
diff --git a/drivers/misc/hx8837.c b/drivers/misc/hx8837.c
new file mode 100644
index 000000000000..3e8924d8c6ec
--- /dev/null
+++ b/drivers/misc/hx8837.c
@@ -0,0 +1,749 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mainly by David Woodhouse, somewhat modified by Jordan Crouse.
+ * Modernized to use managed GPIO, device-tree, etc. by Lubomir Rintel.
+ *
+ * Copyright (C) 2006-2007 Red Hat, Inc.
+ * Copyright (C) 2006-2007 Advanced Micro Devices, Inc.
+ * Copyright (C) 2009 VIA Technology, Inc.
+ * Copyright (C) 2010-2011 Andres Salomon <dilinger@xxxxxxxxxx>
+ * Copyright (C) 2018 Lubomir Rintel <lkundrak@xxxxx>
+ */
+
+#include <linux/module.h>
+#include <linux/backlight.h>
+#include <linux/console.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fb.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+
+/* DCON registers */
+
+#define DCON_REG_ID 0
+#define DCON_REG_MODE 1
+
+#define MODE_PASSTHRU BIT(0)
+#define MODE_SLEEP BIT(1)
+#define MODE_SLEEP_AUTO BIT(2)
+#define MODE_BL_ENABLE BIT(3)
+#define MODE_BLANK BIT(4)
+#define MODE_CSWIZZLE BIT(5)
+#define MODE_COL_AA BIT(6)
+#define MODE_MONO_LUMA BIT(7)
+#define MODE_SCAN_INT BIT(8)
+#define MODE_CLOCKDIV BIT(9)
+#define MODE_DEBUG BIT(14)
+#define MODE_SELFTEST BIT(15)
+
+#define DCON_REG_HRES 0x2
+#define DCON_REG_HTOTAL 0x3
+#define DCON_REG_HSYNC_WIDTH 0x4
+#define DCON_REG_VRES 0x5
+#define DCON_REG_VTOTAL 0x6
+#define DCON_REG_VSYNC_WIDTH 0x7
+#define DCON_REG_TIMEOUT 0x8
+#define DCON_REG_SCAN_INT 0x9
+#define DCON_REG_BRIGHT 0xa
+#define DCON_REG_MEM_OPT_A 0x41
+#define DCON_REG_MEM_OPT_B 0x42
+
+/* Load Delay Locked Loop (DLL) settings for clock delay */
+#define MEM_DLL_CLOCK_DELAY BIT(0)
+/* Memory controller power down function */
+#define MEM_POWER_DOWN BIT(8)
+/* Memory controller software reset */
+#define MEM_SOFT_RESET BIT(0)
+
+/* Status values */
+
+#define DCONSTAT_SCANINT 0
+#define DCONSTAT_SCANINT_DCON 1
+#define DCONSTAT_DISPLAYLOAD 2
+#define DCONSTAT_MISSED 3
+
+/* Source values */
+
+#define DCON_SOURCE_DCON 0
+#define DCON_SOURCE_CPU 1
+
+struct hx8837_priv {
+ struct i2c_client *client;
+ struct fb_info *fbinfo;
+ struct backlight_device *bl_dev;
+
+ wait_queue_head_t waitq;
+ struct work_struct switch_source;
+ struct notifier_block reboot_nb;
+ struct notifier_block panic_nb;
+
+ /* Scanline to interrupt on during resume */
+ ushort resumeline;
+
+ /* Shadow register for the DCON_REG_MODE register */
+ u8 disp_mode;
+
+ /* The current backlight value - this saves us some smbus traffic */
+ u8 bl_val;
+
+ /* Current source, initialized at probe time */
+ int curr_src;
+
+ /* Desired source */
+ int pending_src;
+
+ /* Variables used during switches */
+ bool switched;
+ ktime_t irq_time;
+ ktime_t load_time;
+
+ /* Current output type; true == mono, false == color */
+ bool mono;
+ /* This get set while controlling fb blank state from the driver */
+ bool ignore_fb_events;
+
+ struct gpio_desc *stat0_gpio;
+ struct gpio_desc *stat1_gpio;
+ struct gpio_desc *load_gpio;
+ struct gpio_desc *irq_gpio;
+};
+
+static irqreturn_t hx8837_interrupt(int irq, void *id);
+
+/* I2C structures */
+
+static unsigned short normal_i2c[] = { 0x0d, I2C_CLIENT_END };
+
+static s32 hx8837_write(struct hx8837_priv *priv, u8 reg, u16 val)
+{
+ return i2c_smbus_write_word_data(priv->client, reg, val);
+}
+
+static s32 hx8837_read(struct hx8837_priv *priv, u8 reg)
+{
+ return i2c_smbus_read_word_data(priv->client, reg);
+}
+
+static void hx8837_hw_init(struct hx8837_priv *priv, int is_init)
+{
+ /* SDRAM setup/hold time */
+ hx8837_write(priv, 0x3a, 0xc040);
+ hx8837_write(priv, DCON_REG_MEM_OPT_A, 0x0000); /* clear option bits */
+ hx8837_write(priv, DCON_REG_MEM_OPT_A,
+ MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
+ hx8837_write(priv, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
+
+ /* Colour swizzle, AA, no passthrough, backlight */
+ if (is_init) {
+ priv->disp_mode = MODE_PASSTHRU | MODE_BL_ENABLE |
+ MODE_CSWIZZLE | MODE_COL_AA;
+ }
+ hx8837_write(priv, DCON_REG_MODE, priv->disp_mode);
+
+ /* Set the scanline to interrupt on during resume */
+ hx8837_write(priv, DCON_REG_SCAN_INT, priv->resumeline);
+}
+
+static void hx8837_set_backlight(struct hx8837_priv *priv, u8 level)
+{
+ hx8837_write(priv, DCON_REG_BRIGHT, level);
+
+ /* Purposely turn off the backlight when we go to level 0 */
+ if (level == 0) {
+ priv->disp_mode &= ~MODE_BL_ENABLE;
+ hx8837_write(priv, DCON_REG_MODE, priv->disp_mode);
+ } else if (!(priv->disp_mode & MODE_BL_ENABLE)) {
+ priv->disp_mode |= MODE_BL_ENABLE;
+ hx8837_write(priv, DCON_REG_MODE, priv->disp_mode);
+ }
+}
+
+/* Set the output type to either color or mono */
+static int hx8837_set_mono_mode(struct hx8837_priv *priv, bool enable_mono)
+{
+ if (priv->mono == enable_mono)
+ return 0;
+
+ priv->mono = enable_mono;
+
+ if (enable_mono) {
+ priv->disp_mode &= ~(MODE_CSWIZZLE | MODE_COL_AA);
+ priv->disp_mode |= MODE_MONO_LUMA;
+ } else {
+ priv->disp_mode &= ~(MODE_MONO_LUMA);
+ priv->disp_mode |= MODE_CSWIZZLE | MODE_COL_AA;
+ }
+
+ hx8837_write(priv, DCON_REG_MODE, priv->disp_mode);
+ return 0;
+}
+
+/* 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 hx8837_load_holdoff(struct hx8837_priv *priv)
+{
+ ktime_t delta_t, now;
+
+ while (1) {
+ now = ktime_get();
+ delta_t = ktime_sub(now, priv->load_time);
+ if (ktime_to_ns(delta_t) > NSEC_PER_MSEC * 20)
+ break;
+ mdelay(4);
+ }
+}
+
+static bool hx8837_blank_fb(struct hx8837_priv *priv, bool blank)
+{
+ int err;
+
+ console_lock();
+ if (!lock_fb_info(priv->fbinfo)) {
+ console_unlock();
+ dev_err(&priv->client->dev, "unable to lock framebuffer\n");
+ return false;
+ }
+
+ priv->ignore_fb_events = true;
+ err = fb_blank(priv->fbinfo,
+ blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
+ priv->ignore_fb_events = false;
+ unlock_fb_info(priv->fbinfo);
+ console_unlock();
+
+ if (err) {
+ dev_err(&priv->client->dev, "couldn't %sblank framebuffer\n",
+ blank ? "" : "un");
+ return false;
+ }
+ return true;
+}
+
+/* Set the source of the display (CPU or DCON) */
+static void hx8837_source_switch(struct work_struct *work)
+{
+ struct hx8837_priv *priv = container_of(work, struct hx8837_priv,
+ switch_source);
+ struct device *dev = &priv->client->dev;
+ int source = priv->pending_src;
+
+ if (priv->curr_src == source)
+ return;
+
+ hx8837_load_holdoff(priv);
+
+ priv->switched = false;
+
+ switch (source) {
+ case DCON_SOURCE_CPU:
+ dev_info(dev, "%s to CPU\n", __func__);
+ /* Enable the scanline interrupt bit */
+ if (hx8837_write(priv, DCON_REG_MODE,
+ priv->disp_mode | MODE_SCAN_INT))
+ dev_err(dev, "couldn't enable scanline interrupt!\n");
+ else
+ /* Wait up to one second for the scanline interrupt */
+ wait_event_timeout(priv->waitq, priv->switched, HZ);
+
+ if (!priv->switched)
+ dev_err(dev, "Timeout entering CPU mode; expect a screen glitch.\n");
+
+ /* Turn off the scanline interrupt */
+ if (hx8837_write(priv, DCON_REG_MODE, priv->disp_mode))
+ dev_err(dev, "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 (!hx8837_blank_fb(priv, false)) {
+ dev_err(dev, "Failed to enter CPU mode\n");
+ priv->pending_src = DCON_SOURCE_DCON;
+ return;
+ }
+
+ /* And turn off the DCON */
+ gpiod_set_value(priv->load_gpio, 1);
+ priv->load_time = ktime_get();
+
+ dev_info(dev, "The CPU has control\n");
+ break;
+ case DCON_SOURCE_DCON:
+ dev_info(dev, "%s to DCON\n", __func__);
+
+ /* Clear DCONLOAD - this implies that the DCON is in control */
+ gpiod_set_value(priv->load_gpio, 0);
+ priv->load_time = ktime_get();
+
+ wait_event_timeout(priv->waitq, priv->switched, HZ / 2);
+
+ if (!priv->switched) {
+ dev_err(dev, "Timeout entering DCON mode; expect a screen glitch.\n");
+ } else {
+ ktime_t delta_t;
+
+ /* 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(priv->irq_time, priv->load_time);
+ if (priv->switched && ktime_to_ns(delta_t)
+ < NSEC_PER_MSEC * 20) {
+ dev_err(dev, "missed loading, retrying\n");
+ gpiod_set_value(priv->load_gpio, 1);
+ mdelay(41);
+ gpiod_set_value(priv->load_gpio, 0);
+ priv->load_time = ktime_get();
+ mdelay(41);
+ }
+ }
+
+ hx8837_blank_fb(priv, true);
+ dev_info(dev, "The DCON has control\n");
+ break;
+ default:
+ WARN_ON(1);
+ }
+
+ priv->curr_src = source;
+}
+
+static void hx8837_set_source(struct hx8837_priv *priv, int arg)
+{
+ if (priv->pending_src == arg)
+ return;
+
+ priv->pending_src = arg;
+
+ if (priv->curr_src != arg)
+ schedule_work(&priv->switch_source);
+}
+
+static void hx8837_set_source_sync(struct hx8837_priv *priv, int arg)
+{
+ hx8837_set_source(priv, arg);
+ flush_scheduled_work();
+}
+
+static int hx8837_bl_update(struct backlight_device *dev)
+{
+ struct hx8837_priv *priv = bl_get_data(dev);
+ u8 level = dev->props.brightness & 0x0F;
+
+ priv->bl_val = level;
+
+ if (dev->props.power != FB_BLANK_UNBLANK)
+ level = 0;
+
+ if (dev->props.state & BL_CORE_FBBLANK)
+ level = 0;
+
+ hx8837_set_backlight(priv, level);
+
+ return 0;
+}
+
+static int hx8837_bl_get(struct backlight_device *dev)
+{
+ struct hx8837_priv *priv = bl_get_data(dev);
+
+ return priv->bl_val;
+}
+
+static const struct backlight_ops hx8837_bl_ops = {
+ .update_status = hx8837_bl_update,
+ .get_brightness = hx8837_bl_get,
+};
+
+static struct backlight_properties hx8837_bl_props = {
+ .max_brightness = 15,
+ .type = BACKLIGHT_RAW,
+ .power = FB_BLANK_UNBLANK,
+};
+
+static int hx8837_reboot_notify(struct notifier_block *nb, unsigned long foo,
+ void *bar)
+{
+ struct hx8837_priv *priv = container_of(nb, struct hx8837_priv,
+ reboot_nb);
+
+ /* Turn off the DCON. Entirely. */
+ hx8837_write(priv, DCON_REG_MODE, 0x39);
+ hx8837_write(priv, DCON_REG_MODE, 0x32);
+ return NOTIFY_DONE;
+}
+
+static int hx8837_panic_notify(struct notifier_block *nb, unsigned long e,
+ void *p)
+{
+ struct hx8837_priv *priv = container_of(nb, struct hx8837_priv,
+ panic_nb);
+
+ gpiod_set_value(priv->load_gpio, 1);
+ return NOTIFY_DONE;
+}
+
+static int hx8837_detect(struct i2c_client *client, struct i2c_board_info *info)
+{
+ strlcpy(info->type, "hx8837", I2C_NAME_SIZE);
+
+ return 0;
+}
+
+static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct hx8837_priv *priv = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%4.4X\n", priv->disp_mode);
+}
+
+static ssize_t freeze_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct hx8837_priv *priv = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", priv->curr_src == DCON_SOURCE_DCON ? 1 : 0);
+}
+
+static ssize_t monochrome_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hx8837_priv *priv = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", priv->mono);
+}
+
+static ssize_t resumeline_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct hx8837_priv *priv = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", priv->resumeline);
+}
+
+static ssize_t monochrome_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;
+
+ hx8837_set_mono_mode(dev_get_drvdata(dev), enable_mono ? true : false);
+
+ return count;
+}
+
+static ssize_t freeze_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct hx8837_priv *priv = dev_get_drvdata(dev);
+ unsigned long output;
+ int ret;
+
+ ret = kstrtoul(buf, 10, &output);
+ if (ret)
+ return ret;
+
+ switch (output) {
+ case 0:
+ hx8837_set_source(priv, DCON_SOURCE_CPU);
+ break;
+ case 1:
+ hx8837_set_source_sync(priv, DCON_SOURCE_DCON);
+ break;
+ case 2: /* normally unused */
+ hx8837_set_source(priv, DCON_SOURCE_DCON);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static ssize_t resumeline_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct hx8837_priv *priv = dev_get_drvdata(dev);
+ unsigned short rl;
+ int rc;
+
+ rc = kstrtou16(buf, 10, &rl);
+ if (rc)
+ return rc;
+
+ priv->resumeline = rl;
+ hx8837_write(dev_get_drvdata(dev), DCON_REG_SCAN_INT, priv->resumeline);
+
+ return count;
+}
+
+
+static DEVICE_ATTR_RO(mode);
+static DEVICE_ATTR_RW(freeze);
+static DEVICE_ATTR_RW(monochrome);
+static DEVICE_ATTR_RW(resumeline);
+
+static struct attribute *hx8837_attrs[] = {
+ &dev_attr_mode.attr,
+ &dev_attr_freeze.attr,
+ &dev_attr_monochrome.attr,
+ &dev_attr_resumeline.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(hx8837);
+
+static int hx8837_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct hx8837_priv *priv;
+ u16 ver;
+ int rc;
+
+ if (num_registered_fb < 1)
+ return -EPROBE_DEFER;
+
+ priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->client = client;
+ init_waitqueue_head(&priv->waitq);
+ INIT_WORK(&priv->switch_source, hx8837_source_switch);
+ priv->reboot_nb.notifier_call = hx8837_reboot_notify;
+ priv->reboot_nb.priority = -1;
+ priv->panic_nb.notifier_call = hx8837_panic_notify;
+
+ /*
+ * Perhaps we could add a phandle to the panel to a DT property so that
+ * we'll be able to guess it from the vertical resolution instead of
+ * hardwiring it?
+ */
+ priv->resumeline = 898;
+
+ i2c_set_clientdata(client, priv);
+
+ priv->fbinfo = registered_fb[0];
+
+ priv->stat0_gpio = devm_gpiod_get_index(&client->dev, "stat", 0,
+ GPIOD_IN);
+ if (IS_ERR(priv->stat0_gpio)) {
+ dev_err(&client->dev, "failed to request STAT0 GPIO\n");
+ return PTR_ERR(priv->stat0_gpio);
+ };
+
+ priv->stat1_gpio = devm_gpiod_get_index(&client->dev, "stat", 1,
+ GPIOD_IN);
+ if (IS_ERR(priv->stat1_gpio)) {
+ dev_err(&client->dev, "failed to request STAT1 GPIO\n");
+ return PTR_ERR(priv->stat1_gpio);
+ };
+
+ priv->load_gpio = devm_gpiod_get(&client->dev, "load", GPIOD_IN);
+ if (IS_ERR(priv->load_gpio)) {
+ dev_err(&client->dev, "failed to request LOAD GPIO\n");
+ return PTR_ERR(priv->load_gpio);
+ };
+
+ priv->irq_gpio = devm_gpiod_get(&client->dev, "irq", GPIOD_IN);
+ if (IS_ERR(priv->irq_gpio)) {
+ dev_err(&client->dev, "failed to request IRQ GPIO\n");
+ return PTR_ERR(priv->irq_gpio);
+ };
+
+ ver = hx8837_read(priv, DCON_REG_ID);
+ if ((ver >> 8) != 0xDC) {
+ dev_err(&client->dev, "DCON ID not 0xDCxx: 0x%04x.\n", ver);
+ return -ENXIO;
+ }
+
+ dev_info(&client->dev, "Discovered DCON version %x\n", ver & 0xFF);
+
+ if (ver < 0xdc02) {
+ dev_err(&client->dev, "DCON v1 is unsupported, giving up.\n");
+ return -ENODEV;
+ }
+
+ /*
+ * Determine the current state by reading the GPIO bit; earlier
+ * stages of the boot process have established the state.
+ */
+ priv->curr_src = gpiod_get_value(priv->load_gpio)
+ ? DCON_SOURCE_CPU : DCON_SOURCE_DCON;
+ priv->pending_src = priv->curr_src;
+
+ /* Set the directions for the GPIO pins */
+ gpiod_direction_input(priv->stat0_gpio);
+ gpiod_direction_input(priv->stat1_gpio);
+ gpiod_direction_input(priv->irq_gpio);
+ gpiod_direction_output(priv->load_gpio,
+ priv->curr_src == DCON_SOURCE_CPU);
+
+ /* Register the interrupt handler */
+ rc = devm_request_irq(&client->dev, gpiod_to_irq(priv->irq_gpio),
+ &hx8837_interrupt, IRQF_TRIGGER_FALLING, "DCON", priv);
+ if (rc) {
+ dev_err(&client->dev, "failed to request DCON's irq\n");
+ return rc;
+ }
+
+ hx8837_hw_init(priv, 1);
+
+ priv->bl_val = hx8837_read(priv, DCON_REG_BRIGHT) & 0x0F;
+
+ /* Add the backlight device for the DCON */
+ hx8837_bl_props.brightness = priv->bl_val;
+ priv->bl_dev = devm_backlight_device_register(&client->dev, "hx8837-bl",
+ &client->dev, priv, &hx8837_bl_ops, &hx8837_bl_props);
+ if (IS_ERR(priv->bl_dev)) {
+ dev_err(&client->dev, "cannot register backlight dev (%ld)\n",
+ PTR_ERR(priv->bl_dev));
+ priv->bl_dev = NULL;
+ }
+
+ rc = devm_device_add_groups(&client->dev, hx8837_groups);
+ if (rc) {
+ dev_err(&client->dev, "failed to register sysfs groups\n");
+ return rc;
+ }
+
+ devm_register_reboot_notifier(&client->dev, &priv->reboot_nb);
+ atomic_notifier_chain_register(&panic_notifier_list, &priv->panic_nb);
+
+ return 0;
+}
+
+static int hx8837_remove(struct i2c_client *client)
+{
+ struct hx8837_priv *priv = i2c_get_clientdata(client);
+
+ atomic_notifier_chain_unregister(&panic_notifier_list,
+ &priv->panic_nb);
+
+ cancel_work_sync(&priv->switch_source);
+
+ return 0;
+}
+
+static irqreturn_t hx8837_interrupt(int irq, void *id)
+{
+ struct hx8837_priv *priv = id;
+ struct device *dev = &priv->client->dev;
+ u8 status;
+
+ status = gpiod_get_value(priv->stat0_gpio);
+ status |= gpiod_get_value(priv->stat1_gpio) << 1;
+
+
+ switch (status & 3) {
+ case 3:
+ dev_dbg(dev, "DCONLOAD_MISSED interrupt\n");
+ break;
+
+ case 2: /* switch to DCON mode */
+ case 1: /* switch to CPU mode */
+ priv->switched = true;
+ priv->irq_time = ktime_get();
+ wake_up(&priv->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 (priv->curr_src != priv->pending_src && !priv->switched) {
+ priv->switched = true;
+ priv->irq_time = ktime_get();
+ wake_up(&priv->waitq);
+ dev_dbg(dev, "switching w/ status 0/0\n");
+ } else {
+ dev_dbg(dev, "scanline interrupt w/CPU\n");
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_PM
+static int hx8837_suspend(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hx8837_priv *priv = i2c_get_clientdata(client);
+
+ hx8837_set_source_sync(priv, DCON_SOURCE_DCON);
+
+ return 0;
+}
+
+static int hx8837_resume(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hx8837_priv *priv = i2c_get_clientdata(client);
+
+ hx8837_set_source(priv, DCON_SOURCE_CPU);
+
+ return 0;
+}
+#endif /* CONFIG_PM */
+
+static SIMPLE_DEV_PM_OPS(hx8837_pm_ops, hx8837_suspend, hx8837_resume);
+
+static const struct of_device_id hx8837_dt_ids[] = {
+ { .compatible = "himax,hx8837", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, hx8837_dt_ids);
+
+static const struct i2c_device_id hx8837_i2c_ids[] = {
+ { .name = "hx8837", },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, hx8837_i2c_ids);
+
+static struct i2c_driver hx8837_driver = {
+ .driver = {
+ .name = "hx8837",
+ .pm = &hx8837_pm_ops,
+ .of_match_table = hx8837_dt_ids,
+ },
+ .class = I2C_CLASS_DDC | I2C_CLASS_HWMON,
+ .id_table = hx8837_i2c_ids,
+ .probe = hx8837_probe,
+ .remove = hx8837_remove,
+ .detect = hx8837_detect,
+ .address_list = normal_i2c,
+};
+
+module_i2c_driver(hx8837_driver);
+
+MODULE_DESCRIPTION("HX8837 Display Controller Driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1