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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /drivers/video/backlight/lcd.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'drivers/video/backlight/lcd.c')
-rw-r--r--drivers/video/backlight/lcd.c347
1 files changed, 347 insertions, 0 deletions
diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
new file mode 100644
index 000000000..e918f5760
--- /dev/null
+++ b/drivers/video/backlight/lcd.c
@@ -0,0 +1,347 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LCD Lowlevel Control Abstraction
+ *
+ * Copyright (C) 2003,2004 Hewlett-Packard Company
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/lcd.h>
+#include <linux/notifier.h>
+#include <linux/ctype.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+static DEFINE_MUTEX(lcd_dev_list_mutex);
+static LIST_HEAD(lcd_dev_list);
+
+static void lcd_notify_blank(struct lcd_device *ld, struct device *display_dev,
+ int power)
+{
+ guard(mutex)(&ld->ops_lock);
+
+ if (!ld->ops || !ld->ops->set_power)
+ return;
+ if (ld->ops->controls_device && !ld->ops->controls_device(ld, display_dev))
+ return;
+
+ ld->ops->set_power(ld, power);
+}
+
+void lcd_notify_blank_all(struct device *display_dev, int power)
+{
+ struct lcd_device *ld;
+
+ guard(mutex)(&lcd_dev_list_mutex);
+
+ list_for_each_entry(ld, &lcd_dev_list, entry)
+ lcd_notify_blank(ld, display_dev, power);
+}
+EXPORT_SYMBOL(lcd_notify_blank_all);
+
+static void lcd_notify_mode_change(struct lcd_device *ld, struct device *display_dev,
+ unsigned int width, unsigned int height)
+{
+ guard(mutex)(&ld->ops_lock);
+
+ if (!ld->ops || !ld->ops->set_mode)
+ return;
+ if (ld->ops->controls_device && !ld->ops->controls_device(ld, display_dev))
+ return;
+
+ ld->ops->set_mode(ld, width, height);
+}
+
+void lcd_notify_mode_change_all(struct device *display_dev,
+ unsigned int width, unsigned int height)
+{
+ struct lcd_device *ld;
+
+ guard(mutex)(&lcd_dev_list_mutex);
+
+ list_for_each_entry(ld, &lcd_dev_list, entry)
+ lcd_notify_mode_change(ld, display_dev, width, height);
+}
+EXPORT_SYMBOL(lcd_notify_mode_change_all);
+
+static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int rc;
+ struct lcd_device *ld = to_lcd_device(dev);
+
+ mutex_lock(&ld->ops_lock);
+ if (ld->ops && ld->ops->get_power)
+ rc = sprintf(buf, "%d\n", ld->ops->get_power(ld));
+ else
+ rc = -ENXIO;
+ mutex_unlock(&ld->ops_lock);
+
+ return rc;
+}
+
+static ssize_t lcd_power_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int rc;
+ struct lcd_device *ld = to_lcd_device(dev);
+ unsigned long power;
+
+ rc = kstrtoul(buf, 0, &power);
+ if (rc)
+ return rc;
+
+ rc = -ENXIO;
+
+ mutex_lock(&ld->ops_lock);
+ if (ld->ops && ld->ops->set_power) {
+ pr_debug("set power to %lu\n", power);
+ ld->ops->set_power(ld, power);
+ rc = count;
+ }
+ mutex_unlock(&ld->ops_lock);
+
+ return rc;
+}
+static DEVICE_ATTR_RW(lcd_power);
+
+static ssize_t contrast_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int rc = -ENXIO;
+ struct lcd_device *ld = to_lcd_device(dev);
+
+ mutex_lock(&ld->ops_lock);
+ if (ld->ops && ld->ops->get_contrast)
+ rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld));
+ mutex_unlock(&ld->ops_lock);
+
+ return rc;
+}
+
+static ssize_t contrast_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ int rc;
+ struct lcd_device *ld = to_lcd_device(dev);
+ unsigned long contrast;
+
+ rc = kstrtoul(buf, 0, &contrast);
+ if (rc)
+ return rc;
+
+ rc = -ENXIO;
+
+ mutex_lock(&ld->ops_lock);
+ if (ld->ops && ld->ops->set_contrast) {
+ pr_debug("set contrast to %lu\n", contrast);
+ ld->ops->set_contrast(ld, contrast);
+ rc = count;
+ }
+ mutex_unlock(&ld->ops_lock);
+
+ return rc;
+}
+static DEVICE_ATTR_RW(contrast);
+
+static ssize_t max_contrast_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct lcd_device *ld = to_lcd_device(dev);
+
+ return sprintf(buf, "%d\n", ld->props.max_contrast);
+}
+static DEVICE_ATTR_RO(max_contrast);
+
+static void lcd_device_release(struct device *dev)
+{
+ struct lcd_device *ld = to_lcd_device(dev);
+ kfree(ld);
+}
+
+static struct attribute *lcd_device_attrs[] = {
+ &dev_attr_lcd_power.attr,
+ &dev_attr_contrast.attr,
+ &dev_attr_max_contrast.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(lcd_device);
+
+static const struct class lcd_class = {
+ .name = "lcd",
+ .dev_groups = lcd_device_groups,
+};
+
+/**
+ * lcd_device_register - register a new object of lcd_device class.
+ * @name: the name of the new object(must be the same as the name of the
+ * respective framebuffer device).
+ * @parent: pointer to the parent's struct device .
+ * @devdata: an optional pointer to be stored in the device. The
+ * methods may retrieve it by using lcd_get_data(ld).
+ * @ops: the lcd operations structure.
+ *
+ * Creates and registers a new lcd device. Returns either an ERR_PTR()
+ * or a pointer to the newly allocated device.
+ */
+struct lcd_device *lcd_device_register(const char *name, struct device *parent,
+ void *devdata, const struct lcd_ops *ops)
+{
+ struct lcd_device *new_ld;
+ int rc;
+
+ pr_debug("lcd_device_register: name=%s\n", name);
+
+ new_ld = kzalloc_obj(struct lcd_device);
+ if (!new_ld)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_init(&new_ld->ops_lock);
+ mutex_init(&new_ld->update_lock);
+
+ new_ld->dev.class = &lcd_class;
+ new_ld->dev.parent = parent;
+ new_ld->dev.release = lcd_device_release;
+ dev_set_name(&new_ld->dev, "%s", name);
+ dev_set_drvdata(&new_ld->dev, devdata);
+
+ new_ld->ops = ops;
+
+ rc = device_register(&new_ld->dev);
+ if (rc) {
+ put_device(&new_ld->dev);
+ return ERR_PTR(rc);
+ }
+
+ guard(mutex)(&lcd_dev_list_mutex);
+ list_add(&new_ld->entry, &lcd_dev_list);
+
+ return new_ld;
+}
+EXPORT_SYMBOL(lcd_device_register);
+
+/**
+ * lcd_device_unregister - unregisters a object of lcd_device class.
+ * @ld: the lcd device object to be unregistered and freed.
+ *
+ * Unregisters a previously registered via lcd_device_register object.
+ */
+void lcd_device_unregister(struct lcd_device *ld)
+{
+ if (!ld)
+ return;
+
+ guard(mutex)(&lcd_dev_list_mutex);
+ list_del(&ld->entry);
+
+ mutex_lock(&ld->ops_lock);
+ ld->ops = NULL;
+ mutex_unlock(&ld->ops_lock);
+
+ device_unregister(&ld->dev);
+}
+EXPORT_SYMBOL(lcd_device_unregister);
+
+static void devm_lcd_device_release(struct device *dev, void *res)
+{
+ struct lcd_device *lcd = *(struct lcd_device **)res;
+
+ lcd_device_unregister(lcd);
+}
+
+static int devm_lcd_device_match(struct device *dev, void *res, void *data)
+{
+ struct lcd_device **r = res;
+
+ return *r == data;
+}
+
+/**
+ * devm_lcd_device_register - resource managed lcd_device_register()
+ * @dev: the device to register
+ * @name: the name of the device
+ * @parent: a pointer to the parent device
+ * @devdata: an optional pointer to be stored for private driver use
+ * @ops: the lcd operations structure
+ *
+ * @return a struct lcd on success, or an ERR_PTR on error
+ *
+ * Managed lcd_device_register(). The lcd_device returned from this function
+ * are automatically freed on driver detach. See lcd_device_register()
+ * for more information.
+ */
+struct lcd_device *devm_lcd_device_register(struct device *dev,
+ const char *name, struct device *parent,
+ void *devdata, const struct lcd_ops *ops)
+{
+ struct lcd_device **ptr, *lcd;
+
+ ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ lcd = lcd_device_register(name, parent, devdata, ops);
+ if (!IS_ERR(lcd)) {
+ *ptr = lcd;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return lcd;
+}
+EXPORT_SYMBOL(devm_lcd_device_register);
+
+/**
+ * devm_lcd_device_unregister - resource managed lcd_device_unregister()
+ * @dev: the device to unregister
+ * @ld: the lcd device to unregister
+ *
+ * Deallocated a lcd allocated with devm_lcd_device_register(). Normally
+ * this function will not need to be called and the resource management
+ * code will ensure that the resource is freed.
+ */
+void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld)
+{
+ int rc;
+
+ rc = devres_release(dev, devm_lcd_device_release,
+ devm_lcd_device_match, ld);
+ WARN_ON(rc);
+}
+EXPORT_SYMBOL(devm_lcd_device_unregister);
+
+
+static void __exit lcd_class_exit(void)
+{
+ class_unregister(&lcd_class);
+}
+
+static int __init lcd_class_init(void)
+{
+ int ret;
+
+ ret = class_register(&lcd_class);
+ if (ret) {
+ pr_warn("Unable to create backlight class; errno = %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * if this is compiled into the kernel, we need to ensure that the
+ * class is registered before users of the class try to register lcd's
+ */
+postcore_initcall(lcd_class_init);
+module_exit(lcd_class_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
+MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");