Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 348 insertions, 0 deletions

diff --git a/drivers/video/backlight/mt6370-backlight.c b/drivers/video/backlight/mt6370-backlight.c
new file mode 100644
index 000000000..7905372c2
--- /dev/null
+++ b/drivers/video/backlight/mt6370-backlight.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Richtek Technology Corp.
+ *
+ * Author: ChiaEn Wu <chiaen_wu@richtek.com>
+ */
+
+#include <linux/backlight.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define MT6370_REG_DEV_INFO		0x100
+#define MT6370_REG_BL_EN		0x1A0
+#define MT6370_REG_BL_BSTCTRL		0x1A1
+#define MT6370_REG_BL_PWM		0x1A2
+#define MT6370_REG_BL_DIM2		0x1A4
+
+#define MT6370_VENID_MASK		GENMASK(7, 4)
+#define MT6370_BL_EXT_EN_MASK		BIT(7)
+#define MT6370_BL_EN_MASK		BIT(6)
+#define MT6370_BL_CODE_MASK		BIT(0)
+#define MT6370_BL_CH_MASK		GENMASK(5, 2)
+#define MT6370_BL_CH_SHIFT		2
+#define MT6370_BL_DIM2_COMMON_MASK	GENMASK(2, 0)
+#define MT6370_BL_DIM2_COMMON_SHIFT	3
+#define MT6370_BL_DIM2_6372_MASK	GENMASK(5, 0)
+#define MT6370_BL_DIM2_6372_SHIFT	6
+#define MT6370_BL_PWM_EN_MASK		BIT(7)
+#define MT6370_BL_PWM_HYS_EN_MASK	BIT(2)
+#define MT6370_BL_PWM_HYS_SEL_MASK	GENMASK(1, 0)
+#define MT6370_BL_OVP_EN_MASK		BIT(7)
+#define MT6370_BL_OVP_SEL_MASK		GENMASK(6, 5)
+#define MT6370_BL_OVP_SEL_SHIFT		5
+#define MT6370_BL_OC_EN_MASK		BIT(3)
+#define MT6370_BL_OC_SEL_MASK		GENMASK(2, 1)
+#define MT6370_BL_OC_SEL_SHIFT		1
+
+#define MT6370_BL_PWM_HYS_TH_MIN_STEP	1
+#define MT6370_BL_PWM_HYS_TH_MAX_STEP	64
+#define MT6370_BL_OVP_MIN_UV		17000000
+#define MT6370_BL_OVP_MAX_UV		29000000
+#define MT6370_BL_OVP_STEP_UV		4000000
+#define MT6370_BL_OCP_MIN_UA		900000
+#define MT6370_BL_OCP_MAX_UA		1800000
+#define MT6370_BL_OCP_STEP_UA		300000
+#define MT6370_BL_MAX_COMMON_BRIGHTNESS	2048
+#define MT6370_BL_MAX_6372_BRIGHTNESS	16384
+#define MT6370_BL_MAX_CH		15
+
+enum {
+	MT6370_VID_COMMON = 1,
+	MT6370_VID_6372,
+};
+
+struct mt6370_priv {
+	u8 dim2_mask;
+	u8 dim2_shift;
+	int def_max_brightness;
+	struct backlight_device *bl;
+	struct device *dev;
+	struct gpio_desc *enable_gpio;
+	struct regmap *regmap;
+};
+
+static int mt6370_bl_update_status(struct backlight_device *bl_dev)
+{
+	struct mt6370_priv *priv = bl_get_data(bl_dev);
+	int brightness = backlight_get_brightness(bl_dev);
+	unsigned int enable_val;
+	u8 brightness_val[2];
+	int ret;
+
+	if (brightness) {
+		brightness_val[0] = (brightness - 1) & priv->dim2_mask;
+		brightness_val[1] = (brightness - 1) >> priv->dim2_shift;
+
+		ret = regmap_raw_write(priv->regmap, MT6370_REG_BL_DIM2,
+				       brightness_val, sizeof(brightness_val));
+		if (ret)
+			return ret;
+	}
+
+	gpiod_set_value(priv->enable_gpio, !!brightness);
+
+	enable_val = brightness ? MT6370_BL_EN_MASK : 0;
+	return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN,
+				  MT6370_BL_EN_MASK, enable_val);
+}
+
+static int mt6370_bl_get_brightness(struct backlight_device *bl_dev)
+{
+	struct mt6370_priv *priv = bl_get_data(bl_dev);
+	unsigned int enable;
+	u8 brightness_val[2];
+	int brightness, ret;
+
+	ret = regmap_read(priv->regmap, MT6370_REG_BL_EN, &enable);
+	if (ret)
+		return ret;
+
+	if (!(enable & MT6370_BL_EN_MASK))
+		return 0;
+
+	ret = regmap_raw_read(priv->regmap, MT6370_REG_BL_DIM2,
+			      brightness_val, sizeof(brightness_val));
+	if (ret)
+		return ret;
+
+	brightness = brightness_val[1] << priv->dim2_shift;
+	brightness += brightness_val[0] & priv->dim2_mask;
+
+	return brightness + 1;
+}
+
+static const struct backlight_ops mt6370_bl_ops = {
+	.options = BL_CORE_SUSPENDRESUME,
+	.update_status = mt6370_bl_update_status,
+	.get_brightness = mt6370_bl_get_brightness,
+};
+
+static int mt6370_init_backlight_properties(struct mt6370_priv *priv,
+					    struct backlight_properties *props)
+{
+	struct device *dev = priv->dev;
+	u8 prop_val;
+	u32 brightness, ovp_uV, ocp_uA;
+	unsigned int mask, val;
+	int ret;
+
+	/* Vendor optional properties */
+	val = 0;
+	if (device_property_read_bool(dev, "mediatek,bled-pwm-enable"))
+		val |= MT6370_BL_PWM_EN_MASK;
+
+	if (device_property_read_bool(dev, "mediatek,bled-pwm-hys-enable"))
+		val |= MT6370_BL_PWM_HYS_EN_MASK;
+
+	ret = device_property_read_u8(dev,
+				      "mediatek,bled-pwm-hys-input-th-steps",
+				      &prop_val);
+	if (!ret) {
+		prop_val = clamp_val(prop_val,
+				     MT6370_BL_PWM_HYS_TH_MIN_STEP,
+				     MT6370_BL_PWM_HYS_TH_MAX_STEP);
+		prop_val = prop_val <= 1 ? 0 :
+			   prop_val <= 4 ? 1 :
+			   prop_val <= 16 ? 2 : 3;
+		val |= prop_val;
+	}
+
+	ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_PWM,
+				 val, val);
+	if (ret)
+		return ret;
+
+	val = 0;
+	if (device_property_read_bool(dev, "mediatek,bled-ovp-shutdown"))
+		val |= MT6370_BL_OVP_EN_MASK;
+
+	ret = device_property_read_u32(dev, "mediatek,bled-ovp-microvolt",
+				       &ovp_uV);
+	if (!ret) {
+		ovp_uV = clamp_val(ovp_uV, MT6370_BL_OVP_MIN_UV,
+				   MT6370_BL_OVP_MAX_UV);
+		ovp_uV = DIV_ROUND_UP(ovp_uV - MT6370_BL_OVP_MIN_UV,
+				      MT6370_BL_OVP_STEP_UV);
+		val |= ovp_uV << MT6370_BL_OVP_SEL_SHIFT;
+	}
+
+	if (device_property_read_bool(dev, "mediatek,bled-ocp-shutdown"))
+		val |= MT6370_BL_OC_EN_MASK;
+
+	ret = device_property_read_u32(dev, "mediatek,bled-ocp-microamp",
+				       &ocp_uA);
+	if (!ret) {
+		ocp_uA = clamp_val(ocp_uA, MT6370_BL_OCP_MIN_UA,
+				   MT6370_BL_OCP_MAX_UA);
+		ocp_uA = DIV_ROUND_UP(ocp_uA - MT6370_BL_OCP_MIN_UA,
+				      MT6370_BL_OCP_STEP_UA);
+		val |= ocp_uA << MT6370_BL_OC_SEL_SHIFT;
+	}
+
+	ret = regmap_update_bits(priv->regmap, MT6370_REG_BL_BSTCTRL,
+				 val, val);
+	if (ret)
+		return ret;
+
+	/* Common properties */
+	ret = device_property_read_u32(dev, "max-brightness", &brightness);
+	if (ret)
+		brightness = priv->def_max_brightness;
+
+	props->max_brightness = min_t(u32, brightness, priv->def_max_brightness);
+
+	ret = device_property_read_u32(dev, "default-brightness", &brightness);
+	if (ret)
+		brightness = props->max_brightness;
+
+	props->brightness = min_t(u32, brightness, props->max_brightness);
+
+	val = 0;
+	if (device_property_read_bool(dev, "mediatek,bled-exponential-mode-enable")) {
+		val |= MT6370_BL_CODE_MASK;
+		props->scale = BACKLIGHT_SCALE_NON_LINEAR;
+	} else
+		props->scale = BACKLIGHT_SCALE_LINEAR;
+
+	ret = device_property_read_u8(dev, "mediatek,bled-channel-use",
+				      &prop_val);
+	if (ret) {
+		dev_err(dev, "mediatek,bled-channel-use DT property missing\n");
+		return ret;
+	}
+
+	if (!prop_val || prop_val > MT6370_BL_MAX_CH) {
+		dev_err(dev,
+			"No channel specified or over than upper bound (%d)\n",
+			prop_val);
+		return -EINVAL;
+	}
+
+	mask = MT6370_BL_EXT_EN_MASK | MT6370_BL_CH_MASK;
+	val |= prop_val << MT6370_BL_CH_SHIFT;
+
+	if (priv->enable_gpio)
+		val |= MT6370_BL_EXT_EN_MASK;
+
+	return regmap_update_bits(priv->regmap, MT6370_REG_BL_EN, mask, val);
+}
+
+static int mt6370_check_vendor_info(struct mt6370_priv *priv)
+{
+	/*
+	 * Because MT6372 uses 14 bits to control the brightness,
+	 * MT6370 and MT6371 use 11 bits. This function is used
+	 * to check the vendor's ID and set the relative hardware
+	 * mask, shift and default maximum brightness value that
+	 * should be used.
+	 */
+	unsigned int dev_info, hw_vid, of_vid;
+	int ret;
+
+	ret = regmap_read(priv->regmap, MT6370_REG_DEV_INFO, &dev_info);
+	if (ret)
+		return ret;
+
+	of_vid = (uintptr_t)device_get_match_data(priv->dev);
+	hw_vid = FIELD_GET(MT6370_VENID_MASK, dev_info);
+	hw_vid = (hw_vid == 0x9 || hw_vid == 0xb) ? MT6370_VID_6372 : MT6370_VID_COMMON;
+	if (hw_vid != of_vid)
+		return dev_err_probe(priv->dev, -EINVAL,
+				     "Buggy DT, wrong compatible string\n");
+
+	if (hw_vid == MT6370_VID_6372) {
+		priv->dim2_mask = MT6370_BL_DIM2_6372_MASK;
+		priv->dim2_shift = MT6370_BL_DIM2_6372_SHIFT;
+		priv->def_max_brightness = MT6370_BL_MAX_6372_BRIGHTNESS;
+	} else {
+		priv->dim2_mask = MT6370_BL_DIM2_COMMON_MASK;
+		priv->dim2_shift = MT6370_BL_DIM2_COMMON_SHIFT;
+		priv->def_max_brightness = MT6370_BL_MAX_COMMON_BRIGHTNESS;
+	}
+
+	return 0;
+}
+
+static int mt6370_bl_probe(struct platform_device *pdev)
+{
+	struct backlight_properties props = {
+		.type = BACKLIGHT_RAW,
+	};
+	struct device *dev = &pdev->dev;
+	struct mt6370_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	priv->regmap = dev_get_regmap(dev->parent, NULL);
+	if (!priv->regmap)
+		return dev_err_probe(dev, -ENODEV, "Failed to get regmap\n");
+
+	ret = mt6370_check_vendor_info(priv);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to check vendor info\n");
+
+	priv->enable_gpio = devm_gpiod_get_optional(dev, "enable",
+						    GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->enable_gpio),
+				     "Failed to get 'enable' gpio\n");
+
+	ret = mt6370_init_backlight_properties(priv, &props);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to init backlight properties\n");
+
+	priv->bl = devm_backlight_device_register(dev, pdev->name, dev, priv,
+						  &mt6370_bl_ops, &props);
+	if (IS_ERR(priv->bl))
+		return dev_err_probe(dev, PTR_ERR(priv->bl),
+				     "Failed to register backlight\n");
+
+	backlight_update_status(priv->bl);
+	platform_set_drvdata(pdev, priv);
+
+	return 0;
+}
+
+static void mt6370_bl_remove(struct platform_device *pdev)
+{
+	struct mt6370_priv *priv = platform_get_drvdata(pdev);
+	struct backlight_device *bl_dev = priv->bl;
+
+	bl_dev->props.brightness = 0;
+	backlight_update_status(priv->bl);
+}
+
+static const struct of_device_id mt6370_bl_of_match[] = {
+	{ .compatible = "mediatek,mt6370-backlight", .data = (void *)MT6370_VID_COMMON },
+	{ .compatible = "mediatek,mt6372-backlight", .data = (void *)MT6370_VID_6372 },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mt6370_bl_of_match);
+
+static struct platform_driver mt6370_bl_driver = {
+	.driver = {
+		.name = "mt6370-backlight",
+		.of_match_table = mt6370_bl_of_match,
+	},
+	.probe = mt6370_bl_probe,
+	.remove = mt6370_bl_remove,
+};
+module_platform_driver(mt6370_bl_driver);
+
+MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@richtek.com>");
+MODULE_DESCRIPTION("MediaTek MT6370 Backlight Driver");
+MODULE_LICENSE("GPL v2");