From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 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 --- drivers/hwmon/max127.c | 333 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 333 insertions(+) create mode 100644 drivers/hwmon/max127.c (limited to 'drivers/hwmon/max127.c') diff --git a/drivers/hwmon/max127.c b/drivers/hwmon/max127.c new file mode 100644 index 000000000..b294e86d5 --- /dev/null +++ b/drivers/hwmon/max127.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Hardware monitoring driver for MAX127. + * + * Copyright (c) 2020 Facebook Inc. + */ + +#include +#include +#include +#include +#include + +/* + * MAX127 Control Byte. Refer to MAX127 datasheet, Table 1 "Control-Byte + * Format" for details. + */ +#define MAX127_CTRL_START BIT(7) +#define MAX127_CTRL_SEL_SHIFT 4 +#define MAX127_CTRL_RNG BIT(3) +#define MAX127_CTRL_BIP BIT(2) +#define MAX127_CTRL_PD1 BIT(1) +#define MAX127_CTRL_PD0 BIT(0) + +#define MAX127_NUM_CHANNELS 8 +#define MAX127_SET_CHANNEL(ch) (((ch) & 7) << MAX127_CTRL_SEL_SHIFT) + +/* + * MAX127 channel input ranges. Refer to MAX127 datasheet, Table 3 "Range + * and Polarity Selection" for details. + */ +#define MAX127_FULL_RANGE 10000 /* 10V */ +#define MAX127_HALF_RANGE 5000 /* 5V */ + +/* + * MAX127 returns 2 bytes at read: + * - the first byte contains data[11:4]. + * - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB). + * Refer to MAX127 datasheet, "Read a Conversion (Read Cycle)" section + * for details. + */ +#define MAX127_DATA_LEN 2 +#define MAX127_DATA_SHIFT 4 + +#define MAX127_SIGN_BIT BIT(11) + +struct max127_data { + struct i2c_client *client; + u8 ctrl_byte[MAX127_NUM_CHANNELS]; +}; + +static int max127_select_channel(struct i2c_client *client, u8 ctrl_byte) +{ + int status; + struct i2c_msg msg = { + .addr = client->addr, + .flags = 0, + .len = sizeof(ctrl_byte), + .buf = &ctrl_byte, + }; + + status = i2c_transfer(client->adapter, &msg, 1); + if (status < 0) + return status; + if (status != 1) + return -EIO; + + return 0; +} + +static int max127_read_channel(struct i2c_client *client, long *val) +{ + int status; + u8 i2c_data[MAX127_DATA_LEN]; + struct i2c_msg msg = { + .addr = client->addr, + .flags = I2C_M_RD, + .len = sizeof(i2c_data), + .buf = i2c_data, + }; + + status = i2c_transfer(client->adapter, &msg, 1); + if (status < 0) + return status; + if (status != 1) + return -EIO; + + *val = (i2c_data[1] >> MAX127_DATA_SHIFT) | + ((u16)i2c_data[0] << MAX127_DATA_SHIFT); + return 0; +} + +static long max127_process_raw(u8 ctrl_byte, long raw) +{ + long scale, weight; + + /* + * MAX127's data coding is binary in unipolar mode with 1 LSB = + * (Full-Scale/4096) and two’s complement binary in bipolar mode + * with 1 LSB = [(2 x |FS|)/4096]. + * Refer to MAX127 datasheet, "Transfer Function" section for + * details. + */ + scale = (ctrl_byte & MAX127_CTRL_RNG) ? MAX127_FULL_RANGE : + MAX127_HALF_RANGE; + if (ctrl_byte & MAX127_CTRL_BIP) { + weight = (raw & MAX127_SIGN_BIT); + raw &= ~MAX127_SIGN_BIT; + raw -= weight; + raw *= 2; + } + + return raw * scale / 4096; +} + +static int max127_read_input(struct max127_data *data, int channel, long *val) +{ + long raw; + int status; + struct i2c_client *client = data->client; + u8 ctrl_byte = data->ctrl_byte[channel]; + + status = max127_select_channel(client, ctrl_byte); + if (status) + return status; + + status = max127_read_channel(client, &raw); + if (status) + return status; + + *val = max127_process_raw(ctrl_byte, raw); + return 0; +} + +static int max127_read_min(struct max127_data *data, int channel, long *val) +{ + u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3; + static const int min_input_map[4] = { + 0, /* RNG=0, BIP=0 */ + -MAX127_HALF_RANGE, /* RNG=0, BIP=1 */ + 0, /* RNG=1, BIP=0 */ + -MAX127_FULL_RANGE, /* RNG=1, BIP=1 */ + }; + + *val = min_input_map[rng_bip]; + return 0; +} + +static int max127_read_max(struct max127_data *data, int channel, long *val) +{ + u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3; + static const int max_input_map[4] = { + MAX127_HALF_RANGE, /* RNG=0, BIP=0 */ + MAX127_HALF_RANGE, /* RNG=0, BIP=1 */ + MAX127_FULL_RANGE, /* RNG=1, BIP=0 */ + MAX127_FULL_RANGE, /* RNG=1, BIP=1 */ + }; + + *val = max_input_map[rng_bip]; + return 0; +} + +static int max127_write_min(struct max127_data *data, int channel, long val) +{ + u8 ctrl; + + ctrl = data->ctrl_byte[channel]; + if (val <= -MAX127_FULL_RANGE) { + ctrl |= (MAX127_CTRL_RNG | MAX127_CTRL_BIP); + } else if (val < 0) { + ctrl |= MAX127_CTRL_BIP; + ctrl &= ~MAX127_CTRL_RNG; + } else { + ctrl &= ~MAX127_CTRL_BIP; + } + data->ctrl_byte[channel] = ctrl; + return 0; +} + +static int max127_write_max(struct max127_data *data, int channel, long val) +{ + if (val >= MAX127_FULL_RANGE) + data->ctrl_byte[channel] |= MAX127_CTRL_RNG; + else + data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG; + return 0; +} + +static umode_t max127_is_visible(const void *_data, + enum hwmon_sensor_types type, + u32 attr, int channel) +{ + if (type == hwmon_in) { + switch (attr) { + case hwmon_in_input: + return 0444; + + case hwmon_in_min: + case hwmon_in_max: + return 0644; + + default: + break; + } + } + + return 0; +} + +static int max127_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + int status; + struct max127_data *data = dev_get_drvdata(dev); + + if (type != hwmon_in) + return -EOPNOTSUPP; + + switch (attr) { + case hwmon_in_input: + status = max127_read_input(data, channel, val); + break; + + case hwmon_in_min: + status = max127_read_min(data, channel, val); + break; + + case hwmon_in_max: + status = max127_read_max(data, channel, val); + break; + + default: + status = -EOPNOTSUPP; + break; + } + + return status; +} + +static int max127_write(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long val) +{ + int status; + struct max127_data *data = dev_get_drvdata(dev); + + if (type != hwmon_in) + return -EOPNOTSUPP; + + switch (attr) { + case hwmon_in_min: + status = max127_write_min(data, channel, val); + break; + + case hwmon_in_max: + status = max127_write_max(data, channel, val); + break; + + default: + status = -EOPNOTSUPP; + break; + } + + return status; +} + +static const struct hwmon_ops max127_hwmon_ops = { + .is_visible = max127_is_visible, + .read = max127_read, + .write = max127_write, +}; + +static const struct hwmon_channel_info * const max127_info[] = { + HWMON_CHANNEL_INFO(in, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX, + HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX), + NULL, +}; + +static const struct hwmon_chip_info max127_chip_info = { + .ops = &max127_hwmon_ops, + .info = max127_info, +}; + +static int max127_probe(struct i2c_client *client) +{ + int i; + struct device *hwmon_dev; + struct max127_data *data; + struct device *dev = &client->dev; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->client = client; + for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++) + data->ctrl_byte[i] = (MAX127_CTRL_START | + MAX127_SET_CHANNEL(i)); + + hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, + data, + &max127_chip_info, + NULL); + + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id max127_id[] = { + { .name = "max127" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max127_id); + +static struct i2c_driver max127_driver = { + .driver = { + .name = "max127", + }, + .probe = max127_probe, + .id_table = max127_id, +}; + +module_i2c_driver(max127_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Mike Choi "); +MODULE_AUTHOR("Tao Ren "); +MODULE_DESCRIPTION("MAX127 Hardware Monitoring driver"); -- cgit v1.3.1