kernel/linux.git/drivers/tty/serial/serial_mctrl_gpio.c, branch v6.12.80

serial: mctrl_gpio: split disable_ms into sync and no_sync APIs

2025-05-29T09:02:45+00:00

[ Upstream commit 1bd2aad57da95f7f2d2bb52f7ad15c0f4993a685 ] The following splat has been observed on a SAMA5D27 platform using atmel_serial: BUG: sleeping function called from invalid context at kernel/irq/manage.c:738 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 27, name: kworker/u5:0 preempt_count: 1, expected: 0 INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [<00000000>] 0x0 hardirqs last disabled at (0): [] copy_process+0x1c4c/0x7bec softirqs last enabled at (0): [] copy_process+0x1ca0/0x7bec softirqs last disabled at (0): [<00000000>] 0x0 CPU: 0 UID: 0 PID: 27 Comm: kworker/u5:0 Not tainted 6.13.0-rc7+ #74 Hardware name: Atmel SAMA5 Workqueue: hci0 hci_power_on [bluetooth] Call trace: unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x44/0x70 dump_stack_lvl from __might_resched+0x38c/0x598 __might_resched from disable_irq+0x1c/0x48 disable_irq from mctrl_gpio_disable_ms+0x74/0xc0 mctrl_gpio_disable_ms from atmel_disable_ms.part.0+0x80/0x1f4 atmel_disable_ms.part.0 from atmel_set_termios+0x764/0x11e8 atmel_set_termios from uart_change_line_settings+0x15c/0x994 uart_change_line_settings from uart_set_termios+0x2b0/0x668 uart_set_termios from tty_set_termios+0x600/0x8ec tty_set_termios from ttyport_set_flow_control+0x188/0x1e0 ttyport_set_flow_control from wilc_setup+0xd0/0x524 [hci_wilc] wilc_setup [hci_wilc] from hci_dev_open_sync+0x330/0x203c [bluetooth] hci_dev_open_sync [bluetooth] from hci_dev_do_open+0x40/0xb0 [bluetooth] hci_dev_do_open [bluetooth] from hci_power_on+0x12c/0x664 [bluetooth] hci_power_on [bluetooth] from process_one_work+0x998/0x1a38 process_one_work from worker_thread+0x6e0/0xfb4 worker_thread from kthread+0x3d4/0x484 kthread from ret_from_fork+0x14/0x28 This warning is emitted when trying to toggle, at the highest level, some flow control (with serdev_device_set_flow_control) in a device driver. At the lowest level, the atmel_serial driver is using serial_mctrl_gpio lib to enable/disable the corresponding IRQs accordingly. The warning emitted by CONFIG_DEBUG_ATOMIC_SLEEP is due to disable_irq (called in mctrl_gpio_disable_ms) being possibly called in some atomic context (some tty drivers perform modem lines configuration in regions protected by port lock). Split mctrl_gpio_disable_ms into two differents APIs, a non-blocking one and a blocking one. Replace mctrl_gpio_disable_ms calls with the relevant version depending on whether the call is protected by some port lock. Suggested-by: Jiri Slaby Signed-off-by: Alexis Lothoré Acked-by: Richard Genoud Link: https://lore.kernel.org/r/20250217-atomic_sleep_mctrl_serial_gpio-v3-1-59324b313eef@bootlin.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: add missing MODULE_DESCRIPTION() macros

2024-06-24T14:10:11+00:00

make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/serial/8250/8250_base.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/serial/8250/8250_pxa.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/serial/8250/serial_cs.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/serial/esp32_uart.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/serial/esp32_acm.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/serial/owl-uart.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/n_hdlc.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/n_gsm.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/ttynull.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/tty/goldfish.o Add all missing invocations of the MODULE_DESCRIPTION() macro. Signed-off-by: Jeff Johnson Link: https://lore.kernel.org/r/20240607-md-drivers-tty-v1-1-50a7efb8bed8@quicinc.com Signed-off-by: Greg Kroah-Hartman

serial: mctrl_gpio: Use port lock wrappers

2023-09-18T09:18:14+00:00

When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-59-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman

Documentation: serial: move GPIO kernel-doc to the functions

2022-07-28T08:37:42+00:00

The GPIO uart functions are documented in Documentation. Move and transform this documentation into kernel-doc directly in the code and reference it in Documentation using kernel-doc:. This makes it easier to update, maintain and check by the build. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220728061056.20799-3-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

serial: mctrl_gpio: add a new API to enable / disable wake_irq

2022-02-08T10:07:16+00:00

Add a new API to enable / disable wake_irq in order to enable gpio irqs as wakeup irqs for the uart port. Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20220203171644.12231-2-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman

serial: mctrl_gpio: Fix passing zero to 'ERR_PTR' warning

2020-11-06T16:12:05+00:00

drivers/tty/serial/serial_mctrl_gpio.c:214 mctrl_gpio_init() warn: passing zero to 'ERR_PTR' gpiod_to_irq() never return 0, so remove the useless test and make code more clear. Reviewed-by: Jiri Slaby Signed-off-by: YueHaibing Link: https://lore.kernel.org/r/20201031030530.1304-1-yuehaibing@huawei.com Signed-off-by: Greg Kroah-Hartman

serial: mctrl_gpio: Check for NULL pointer

2019-10-07T11:21:54+00:00

When using mctrl_gpio_to_gpiod, it dereferences gpios into a single requested GPIO. This dereferencing can break if gpios is NULL, so this patch adds a NULL check before dereferencing it. If gpios is NULL, this function will also return NULL. Signed-off-by: Adam Ford Reviewed-by: Yegor Yefremov Link: https://lore.kernel.org/r/20191006163314.23191-1-aford173@gmail.com Signed-off-by: Greg Kroah-Hartman

serial: mctrl_gpio: Use gpiod flags directly

2019-09-04T10:43:55+00:00

Description of the modem line control GPIOs contain a boolean type to set direction of the line. Since GPIO library provides an enumerator type of flags, we may utilize it and allow a bit more flexibility on the choice of the type of the line parameters. It also removes an additional layer of value conversion. Signed-off-by: Andy Shevchenko Reviewed-by: Stefan Roese Reviewed-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20190814140759.17486-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: mctrl_gpio: Check if GPIO property exisits before requesting it

2019-06-21T08:18:43+00:00

This patch adds a check for the GPIOs property existence, before the GPIO is requested. This fixes an issue seen when the 8250 mctrl_gpio support is added (2nd patch in this patch series) on x86 platforms using ACPI. Here Mika's comments from 2016-08-09: " I noticed that with v4.8-rc1 serial console of some of our Broxton systems does not work properly anymore. I'm able to see output but input does not work. I bisected it down to commit 4ef03d328769eddbfeca1f1c958fdb181a69c341 ("tty/serial/8250: use mctrl_gpio helpers"). The reason why it fails is that in ACPI we do not have names for GPIOs (except when _DSD is used) so we use the "idx" to index into _CRS GPIO resources. Now mctrl_gpio_init_noauto() goes through a list of GPIOs calling devm_gpiod_get_index_optional() passing "idx" of 0 for each. The UART device in Broxton has following (simplified) ACPI description: Device (URT4) { ... Name (_CRS, ResourceTemplate () { GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly, "\\_SB.GPO0", 0x00, ResourceConsumer) { 0x003A } GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly, "\\_SB.GPO0", 0x00, ResourceConsumer) { 0x003D } }) In this case it finds the first GPIO (0x003A which happens to be RX pin for that UART), turns it into GPIO which then breaks input for the UART device. This also breaks systems with bluetooth connected to UART (those typically have some GPIOs in their _CRS). Any ideas how to fix this? We cannot just drop the _CRS index lookup fallback because that would break many existing machines out there so maybe we can limit this to only DT enabled machines. Or alternatively probe if the property first exists before trying to acquire the GPIOs (using device_property_present()). " This patch implements the fix suggested by Mika in his statement above. Signed-off-by: Stefan Roese Reviewed-by: Mika Westerberg Reviewed-by: Andy Shevchenko Tested-by: Yegor Yefremov Cc: Mika Westerberg Cc: Andy Shevchenko Cc: Yegor Yefremov Cc: Greg Kroah-Hartman Cc: Giulio Benetti Signed-off-by: Greg Kroah-Hartman

gpiolib: Pass array info to get/set array functions

2018-09-13T09:16:54+00:00

In order to make use of array info obtained from gpiod_get_array() and speed up processing of arrays matching single GPIO chip layout, that information must be passed to get/set array functions. Extend the functions' API with that additional parameter and update all users. Pass NULL if a user builds an array itself from single GPIOs. Cc: Jonathan Corbet Cc: Miguel Ojeda Sandonis Cc: Geert Uytterhoeven Cc: Sebastien Bourdelin Cc: Lukas Wunner Cc: Peter Korsgaard Cc: Peter Rosin Cc: Andrew Lunn Cc: Florian Fainelli Cc: "David S. Miller" Cc: Rojhalat Ibrahim Cc: Dominik Brodowski Cc: Russell King Cc: Kishon Vijay Abraham I Cc: Tony Lindgren Cc: Lars-Peter Clausen Cc: Michael Hennerich Cc: Jonathan Cameron Cc: Hartmut Knaack Cc: Peter Meerwald-Stadler Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: Yegor Yefremov Cc: Uwe Kleine-König Signed-off-by: Janusz Krzysztofik Acked-by: Ulf Hansson Signed-off-by: Linus Walleij