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/mfd/max7360.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 drivers/mfd/max7360.c (limited to 'drivers/mfd/max7360.c') diff --git a/drivers/mfd/max7360.c b/drivers/mfd/max7360.c new file mode 100644 index 000000000..52fffed0c --- /dev/null +++ b/drivers/mfd/max7360.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Maxim MAX7360 Core Driver + * + * Copyright 2025 Bootlin + * + * Authors: + * Kamel Bouhara + * Mathieu Dubois-Briand + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static const struct mfd_cell max7360_cells[] = { + { .name = "max7360-pinctrl" }, + { .name = "max7360-pwm" }, + { .name = "max7360-keypad" }, + { .name = "max7360-rotary" }, + { + .name = "max7360-gpo", + .of_compatible = "maxim,max7360-gpo", + }, + { + .name = "max7360-gpio", + .of_compatible = "maxim,max7360-gpio", + }, +}; + +static const struct regmap_range max7360_volatile_ranges[] = { + regmap_reg_range(MAX7360_REG_KEYFIFO, MAX7360_REG_KEYFIFO), + regmap_reg_range(MAX7360_REG_I2C_TIMEOUT, MAX7360_REG_RTR_CNT), +}; + +static const struct regmap_access_table max7360_volatile_table = { + .yes_ranges = max7360_volatile_ranges, + .n_yes_ranges = ARRAY_SIZE(max7360_volatile_ranges), +}; + +static const struct regmap_config max7360_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MAX7360_REG_PWMCFG(MAX7360_PORT_PWM_COUNT - 1), + .volatile_table = &max7360_volatile_table, + .cache_type = REGCACHE_MAPLE, +}; + +static int max7360_mask_irqs(struct regmap *regmap) +{ + struct device *dev = regmap_get_device(regmap); + unsigned int val; + int ret; + + /* + * GPIO/PWM interrupts are not masked on reset: as the MAX7360 "INTI" + * interrupt line is shared between GPIOs and rotary encoder, this could + * result in repeated spurious interrupts on the rotary encoder driver + * if the GPIO driver is not loaded. Mask them now to avoid this + * situation. + */ + for (unsigned int i = 0; i < MAX7360_PORT_PWM_COUNT; i++) { + ret = regmap_write_bits(regmap, MAX7360_REG_PWMCFG(i), + MAX7360_PORT_CFG_INTERRUPT_MASK, + MAX7360_PORT_CFG_INTERRUPT_MASK); + if (ret) + return dev_err_probe(dev, ret, + "Failed to write MAX7360 port configuration\n"); + } + + /* Read GPIO in register, to ACK any pending IRQ. */ + ret = regmap_read(regmap, MAX7360_REG_GPIOIN, &val); + if (ret) + return dev_err_probe(dev, ret, "Failed to read GPIO values\n"); + + return 0; +} + +static int max7360_reset(struct regmap *regmap) +{ + struct device *dev = regmap_get_device(regmap); + int ret; + + ret = regmap_write(regmap, MAX7360_REG_GPIOCFG, MAX7360_GPIO_CFG_GPIO_RST); + if (ret) { + dev_err(dev, "Failed to reset GPIO configuration: %x\n", ret); + return ret; + } + + ret = regcache_drop_region(regmap, MAX7360_REG_GPIOCFG, MAX7360_REG_GPIO_LAST); + if (ret) { + dev_err(dev, "Failed to drop regmap cache: %x\n", ret); + return ret; + } + + ret = regmap_write(regmap, MAX7360_REG_SLEEP, 0); + if (ret) { + dev_err(dev, "Failed to reset autosleep configuration: %x\n", ret); + return ret; + } + + ret = regmap_write(regmap, MAX7360_REG_DEBOUNCE, 0); + if (ret) + dev_err(dev, "Failed to reset GPO port count: %x\n", ret); + + return ret; +} + +static int max7360_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct regmap *regmap; + int ret; + + regmap = devm_regmap_init_i2c(client, &max7360_regmap_config); + if (IS_ERR(regmap)) + return dev_err_probe(dev, PTR_ERR(regmap), "Failed to initialise regmap\n"); + + ret = max7360_reset(regmap); + if (ret) + return dev_err_probe(dev, ret, "Failed to reset device\n"); + + /* Get the device out of shutdown mode. */ + ret = regmap_write_bits(regmap, MAX7360_REG_GPIOCFG, + MAX7360_GPIO_CFG_GPIO_EN, + MAX7360_GPIO_CFG_GPIO_EN); + if (ret) + return dev_err_probe(dev, ret, "Failed to enable GPIO and PWM module\n"); + + ret = max7360_mask_irqs(regmap); + if (ret) + return dev_err_probe(dev, ret, "Could not mask interrupts\n"); + + ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE, + max7360_cells, ARRAY_SIZE(max7360_cells), + NULL, 0, NULL); + if (ret) + return dev_err_probe(dev, ret, "Failed to register child devices\n"); + + return 0; +} + +static const struct of_device_id max7360_dt_match[] = { + { .compatible = "maxim,max7360" }, + {} +}; +MODULE_DEVICE_TABLE(of, max7360_dt_match); + +static struct i2c_driver max7360_driver = { + .driver = { + .name = "max7360", + .of_match_table = max7360_dt_match, + }, + .probe = max7360_probe, +}; +module_i2c_driver(max7360_driver); + +MODULE_DESCRIPTION("Maxim MAX7360 I2C IO Expander core driver"); +MODULE_AUTHOR("Kamel Bouhara "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1