kernel/drivers/tty/serial/serial_mctrl_gpio.c, branch linux-6.9.y

serial: mctrl_gpio: Use port lock wrappers

2023-09-18T09:18:14Z

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

2022-07-28T08:37:42Z

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

2022-02-08T10:07:16Z

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

2020-11-06T16:12:05Z

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

2019-10-07T11:21:54Z

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

2019-09-04T10:43:55Z

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

2019-06-21T08:18:43Z

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

2018-09-13T09:16:54Z

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

gpiolib: Pass bitmaps, not integer arrays, to get/set array

2018-09-13T09:15:30Z

Most users of get/set array functions iterate consecutive bits of data, usually a single integer, while processing array of results obtained from, or building an array of values to be passed to those functions. Save time wasted on those iterations by changing the functions' API to accept bitmaps. All current users are updated as well. More benefits from the change are expected as soon as planned support for accepting/passing those bitmaps directly from/to respective GPIO chip callbacks if applicable is implemented. Cc: Jonathan Corbet Cc: Miguel Ojeda Sandonis 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 Reviewed-by: Geert Uytterhoeven Tested-by: Geert Uytterhoeven Signed-off-by: Linus Walleij

tty: serial: Remove redundant license text

2017-11-08T12:08:12Z

Now that the SPDX tag is in all tty files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Jiri Slaby Cc: Eric Anholt Cc: Stefan Wahren Cc: Florian Fainelli Cc: Ray Jui Cc: Scott Branden Cc: bcm-kernel-feedback-list@broadcom.com Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Joachim Eastwood Cc: Matthias Brugger Cc: Masahiro Yamada Cc: Tobias Klauser Cc: Russell King Cc: Vineet Gupta Cc: Richard Genoud Cc: Alexander Shiyan Cc: Baruch Siach Cc: Pat Gefre Cc: "Guilherme G. Piccoli" Cc: Jason Wessel Cc: Vladimir Zapolskiy Cc: Sylvain Lemieux Cc: Carlo Caione Cc: Kevin Hilman Cc: Liviu Dudau Cc: Sudeep Holla Cc: Lorenzo Pieralisi Cc: Andy Gross Cc: David Brown Cc: "Andreas Färber" Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Kevin Cernekee Cc: Laxman Dewangan Cc: Thierry Reding Cc: Jonathan Hunter Cc: Barry Song Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: Chris Metcalf Cc: Peter Korsgaard Cc: Timur Tabi Cc: Tony Prisk Cc: Michal Simek Cc: "Sören Brinkmann" Signed-off-by: Greg Kroah-Hartman