From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/input/misc/max7360-rotary.c | 192 ++++++++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 drivers/input/misc/max7360-rotary.c (limited to 'drivers/input/misc/max7360-rotary.c') diff --git a/drivers/input/misc/max7360-rotary.c b/drivers/input/misc/max7360-rotary.c new file mode 100644 index 000000000..385831ef3 --- /dev/null +++ b/drivers/input/misc/max7360-rotary.c @@ -0,0 +1,192 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2025 Bootlin + * + * Author: Mathieu Dubois-Briand + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define MAX7360_ROTARY_DEFAULT_STEPS 24 + +struct max7360_rotary { + struct input_dev *input; + struct regmap *regmap; + unsigned int debounce_ms; + + unsigned int pos; + + u32 steps; + u32 axis; + bool relative_axis; + bool rollover; +}; + +static void max7360_rotary_report_event(struct max7360_rotary *max7360_rotary, int steps) +{ + if (max7360_rotary->relative_axis) { + input_report_rel(max7360_rotary->input, max7360_rotary->axis, steps); + } else { + int pos = max7360_rotary->pos; + int maxval = max7360_rotary->steps; + + /* + * Add steps to the position. + * Make sure added steps are always in ]-maxval; maxval[ + * interval, so (pos + maxval) is always >= 0. + * Then set back pos to the [0; maxval[ interval. + */ + pos += steps % maxval; + if (max7360_rotary->rollover) + pos = (pos + maxval) % maxval; + else + pos = clamp(pos, 0, maxval - 1); + + max7360_rotary->pos = pos; + input_report_abs(max7360_rotary->input, max7360_rotary->axis, max7360_rotary->pos); + } + + input_sync(max7360_rotary->input); +} + +static irqreturn_t max7360_rotary_irq(int irq, void *data) +{ + struct max7360_rotary *max7360_rotary = data; + struct device *dev = max7360_rotary->input->dev.parent; + unsigned int val; + int error; + + error = regmap_read(max7360_rotary->regmap, MAX7360_REG_RTR_CNT, &val); + if (error < 0) { + dev_err(dev, "Failed to read rotary counter\n"); + return IRQ_NONE; + } + + if (val == 0) + return IRQ_NONE; + + max7360_rotary_report_event(max7360_rotary, sign_extend32(val, 7)); + + return IRQ_HANDLED; +} + +static int max7360_rotary_hw_init(struct max7360_rotary *max7360_rotary) +{ + struct device *dev = max7360_rotary->input->dev.parent; + int val; + int error; + + val = FIELD_PREP(MAX7360_ROT_DEBOUNCE, max7360_rotary->debounce_ms) | + FIELD_PREP(MAX7360_ROT_INTCNT, 1) | MAX7360_ROT_INTCNT_DLY; + error = regmap_write(max7360_rotary->regmap, MAX7360_REG_RTRCFG, val); + if (error) + dev_err(dev, "Failed to set max7360 rotary encoder configuration\n"); + + return error; +} + +static int max7360_rotary_probe(struct platform_device *pdev) +{ + struct max7360_rotary *max7360_rotary; + struct device *dev = &pdev->dev; + struct input_dev *input; + struct regmap *regmap; + int irq; + int error; + + regmap = dev_get_regmap(dev->parent, NULL); + if (!regmap) + return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n"); + + irq = fwnode_irq_get_byname(dev_fwnode(dev->parent), "inti"); + if (irq < 0) + return dev_err_probe(dev, irq, "Failed to get IRQ\n"); + + max7360_rotary = devm_kzalloc(dev, sizeof(*max7360_rotary), GFP_KERNEL); + if (!max7360_rotary) + return -ENOMEM; + + max7360_rotary->regmap = regmap; + + device_property_read_u32(dev->parent, "linux,axis", &max7360_rotary->axis); + max7360_rotary->rollover = device_property_read_bool(dev->parent, + "rotary-encoder,rollover"); + max7360_rotary->relative_axis = + device_property_read_bool(dev->parent, "rotary-encoder,relative-axis"); + + error = device_property_read_u32(dev->parent, "rotary-encoder,steps", + &max7360_rotary->steps); + if (error) + max7360_rotary->steps = MAX7360_ROTARY_DEFAULT_STEPS; + + device_property_read_u32(dev->parent, "rotary-debounce-delay-ms", + &max7360_rotary->debounce_ms); + if (max7360_rotary->debounce_ms > MAX7360_ROT_DEBOUNCE_MAX) + return dev_err_probe(dev, -EINVAL, "Invalid debounce timing: %u\n", + max7360_rotary->debounce_ms); + + input = devm_input_allocate_device(dev); + if (!input) + return -ENOMEM; + + max7360_rotary->input = input; + + input->id.bustype = BUS_I2C; + input->name = pdev->name; + + if (max7360_rotary->relative_axis) + input_set_capability(input, EV_REL, max7360_rotary->axis); + else + input_set_abs_params(input, max7360_rotary->axis, 0, max7360_rotary->steps, 0, 1); + + error = devm_request_threaded_irq(dev, irq, NULL, max7360_rotary_irq, + IRQF_ONESHOT | IRQF_SHARED, + "max7360-rotary", max7360_rotary); + if (error) + return dev_err_probe(dev, error, "Failed to register interrupt\n"); + + error = input_register_device(input); + if (error) + return dev_err_probe(dev, error, "Could not register input device\n"); + + error = max7360_rotary_hw_init(max7360_rotary); + if (error) + return dev_err_probe(dev, error, "Failed to initialize max7360 rotary\n"); + + device_init_wakeup(dev, true); + error = dev_pm_set_wake_irq(dev, irq); + if (error) + dev_warn(dev, "Failed to set up wakeup irq: %d\n", error); + + return 0; +} + +static void max7360_rotary_remove(struct platform_device *pdev) +{ + dev_pm_clear_wake_irq(&pdev->dev); + device_init_wakeup(&pdev->dev, false); +} + +static struct platform_driver max7360_rotary_driver = { + .driver = { + .name = "max7360-rotary", + }, + .probe = max7360_rotary_probe, + .remove = max7360_rotary_remove, +}; +module_platform_driver(max7360_rotary_driver); + +MODULE_DESCRIPTION("MAX7360 Rotary driver"); +MODULE_AUTHOR("Mathieu Dubois-Briand "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1