From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/misc/apds9802als.c | 308 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 308 insertions(+) create mode 100644 drivers/misc/apds9802als.c (limited to 'drivers/misc/apds9802als.c') diff --git a/drivers/misc/apds9802als.c b/drivers/misc/apds9802als.c new file mode 100644 index 000000000..fc504bd8d --- /dev/null +++ b/drivers/misc/apds9802als.c @@ -0,0 +1,308 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * apds9802als.c - apds9802 ALS Driver + * + * Copyright (C) 2009 Intel Corp + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define ALS_MIN_RANGE_VAL 1 +#define ALS_MAX_RANGE_VAL 2 +#define POWER_STA_ENABLE 1 +#define POWER_STA_DISABLE 0 + +#define DRIVER_NAME "apds9802als" + +struct als_data { + struct mutex mutex; +}; + +static ssize_t als_sensing_range_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + int val; + + val = i2c_smbus_read_byte_data(client, 0x81); + if (val < 0) + return val; + if (val & 1) + return sprintf(buf, "4095\n"); + else + return sprintf(buf, "65535\n"); +} + +static int als_wait_for_data_ready(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + int ret; + int retry = 10; + + do { + msleep(30); + ret = i2c_smbus_read_byte_data(client, 0x86); + } while (!(ret & 0x80) && retry--); + + if (retry < 0) { + dev_warn(dev, "timeout waiting for data ready\n"); + return -ETIMEDOUT; + } + + return 0; +} + +static ssize_t als_lux0_input_data_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + struct als_data *data = i2c_get_clientdata(client); + int ret_val; + int temp; + + /* Protect against parallel reads */ + pm_runtime_get_sync(dev); + mutex_lock(&data->mutex); + + /* clear EOC interrupt status */ + i2c_smbus_write_byte(client, 0x40); + /* start measurement */ + temp = i2c_smbus_read_byte_data(client, 0x81); + i2c_smbus_write_byte_data(client, 0x81, temp | 0x08); + + ret_val = als_wait_for_data_ready(dev); + if (ret_val < 0) + goto failed; + + temp = i2c_smbus_read_byte_data(client, 0x8C); /* LSB data */ + if (temp < 0) { + ret_val = temp; + goto failed; + } + ret_val = i2c_smbus_read_byte_data(client, 0x8D); /* MSB data */ + if (ret_val < 0) + goto failed; + + mutex_unlock(&data->mutex); + pm_runtime_put_sync(dev); + + temp = (ret_val << 8) | temp; + return sprintf(buf, "%d\n", temp); +failed: + mutex_unlock(&data->mutex); + pm_runtime_put_sync(dev); + return ret_val; +} + +static ssize_t als_sensing_range_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct als_data *data = i2c_get_clientdata(client); + int ret_val; + unsigned long val; + + ret_val = kstrtoul(buf, 10, &val); + if (ret_val) + return ret_val; + + if (val < 4096) + val = 1; + else if (val < 65536) + val = 2; + else + return -ERANGE; + + pm_runtime_get_sync(dev); + + /* Make sure nobody else reads/modifies/writes 0x81 while we + are active */ + mutex_lock(&data->mutex); + + ret_val = i2c_smbus_read_byte_data(client, 0x81); + if (ret_val < 0) + goto fail; + + /* Reset the bits before setting them */ + ret_val = ret_val & 0xFA; + + if (val == 1) /* Setting detection range up to 4k LUX */ + ret_val = (ret_val | 0x01); + else /* Setting detection range up to 64k LUX*/ + ret_val = (ret_val | 0x00); + + ret_val = i2c_smbus_write_byte_data(client, 0x81, ret_val); + + if (ret_val >= 0) { + /* All OK */ + mutex_unlock(&data->mutex); + pm_runtime_put_sync(dev); + return count; + } +fail: + mutex_unlock(&data->mutex); + pm_runtime_put_sync(dev); + return ret_val; +} + +static int als_set_power_state(struct i2c_client *client, bool on_off) +{ + int ret_val; + struct als_data *data = i2c_get_clientdata(client); + + mutex_lock(&data->mutex); + ret_val = i2c_smbus_read_byte_data(client, 0x80); + if (ret_val < 0) + goto fail; + if (on_off) + ret_val = ret_val | 0x01; + else + ret_val = ret_val & 0xFE; + ret_val = i2c_smbus_write_byte_data(client, 0x80, ret_val); +fail: + mutex_unlock(&data->mutex); + return ret_val; +} + +static DEVICE_ATTR(lux0_sensor_range, S_IRUGO | S_IWUSR, + als_sensing_range_show, als_sensing_range_store); +static DEVICE_ATTR(lux0_input, S_IRUGO, als_lux0_input_data_show, NULL); + +static struct attribute *mid_att_als[] = { + &dev_attr_lux0_sensor_range.attr, + &dev_attr_lux0_input.attr, + NULL +}; + +static const struct attribute_group m_als_gr = { + .name = "apds9802als", + .attrs = mid_att_als +}; + +static int als_set_default_config(struct i2c_client *client) +{ + int ret_val; + /* Write the command and then switch on */ + ret_val = i2c_smbus_write_byte_data(client, 0x80, 0x01); + if (ret_val < 0) { + dev_err(&client->dev, "failed default switch on write\n"); + return ret_val; + } + /* detection range: 1~64K Lux, maunal measurement */ + ret_val = i2c_smbus_write_byte_data(client, 0x81, 0x08); + if (ret_val < 0) + dev_err(&client->dev, "failed default LUX on write\n"); + + /* We always get 0 for the 1st measurement after system power on, + * so make sure it is finished before user asks for data. + */ + als_wait_for_data_ready(&client->dev); + + return ret_val; +} + +static int apds9802als_probe(struct i2c_client *client) +{ + int res; + struct als_data *data; + + data = kzalloc_obj(struct als_data); + if (data == NULL) { + dev_err(&client->dev, "Memory allocation failed\n"); + return -ENOMEM; + } + i2c_set_clientdata(client, data); + res = sysfs_create_group(&client->dev.kobj, &m_als_gr); + if (res) { + dev_err(&client->dev, "device create file failed\n"); + goto als_error1; + } + dev_info(&client->dev, "ALS chip found\n"); + als_set_default_config(client); + mutex_init(&data->mutex); + + pm_runtime_set_active(&client->dev); + pm_runtime_enable(&client->dev); + + return res; +als_error1: + kfree(data); + return res; +} + +static void apds9802als_remove(struct i2c_client *client) +{ + struct als_data *data = i2c_get_clientdata(client); + + pm_runtime_get_sync(&client->dev); + + als_set_power_state(client, false); + sysfs_remove_group(&client->dev.kobj, &m_als_gr); + + pm_runtime_disable(&client->dev); + pm_runtime_set_suspended(&client->dev); + pm_runtime_put_noidle(&client->dev); + + kfree(data); +} + +#ifdef CONFIG_PM + +static int apds9802als_suspend(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + + als_set_power_state(client, false); + return 0; +} + +static int apds9802als_resume(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + + als_set_power_state(client, true); + return 0; +} + +static UNIVERSAL_DEV_PM_OPS(apds9802als_pm_ops, apds9802als_suspend, + apds9802als_resume, NULL); + +#define APDS9802ALS_PM_OPS (&apds9802als_pm_ops) + +#else /* CONFIG_PM */ +#define APDS9802ALS_PM_OPS NULL +#endif /* CONFIG_PM */ + +static const struct i2c_device_id apds9802als_id[] = { + { DRIVER_NAME }, + { } +}; + +MODULE_DEVICE_TABLE(i2c, apds9802als_id); + +static struct i2c_driver apds9802als_driver = { + .driver = { + .name = DRIVER_NAME, + .pm = APDS9802ALS_PM_OPS, + }, + .probe = apds9802als_probe, + .remove = apds9802als_remove, + .id_table = apds9802als_id, +}; + +module_i2c_driver(apds9802als_driver); + +MODULE_AUTHOR("Anantha Narayanan