On Wed, 8 Jul 2026 14:15:55 +0200, Miao Wang <[email protected]> said: > Hi > >> 2026年7月8日 19:36，Bartosz Golaszewski <[email protected]> 写道： >> >> On Tue, 7 Jul 2026 23:16:31 +0200, Miao Wang via B4 Relay >> <[email protected]> said: >>> From: Miao Wang <[email protected]> >>> >>> The reset event of BMC is captured through GPIO. However, this driver >>> bypasses the GPIO framework and directly accesses the GPIO controller >>> through the fixed address. When the same GPIO controller is also >>> exposed through ACPI and probed by the corresponding GPIO driver, >>> there would be a conflict between the two drivers. >>> >>> This patch will try to find the GPIO through declared GPIO pin in the >>> _CRS resources of the ACPI node. If no such delaration is found, the >>> driver will fall back to search for the correct GPIO controller and pin >>> according to the fixed address and pin number. A possible DSDT >>> declaration for the GPIO pin might be as follows: >>> >>> Device (BMC0) { >>> Name (_ADR, ...) // Match the PCI address of the BMC device >>> // \_SB.GPO1 is the ACPI path of the GPIO controller >>> Name (_CRS, ResourceTemplate () { >>> GpioInt (Edge, ActiveLow, Exclusive, PullNone, 0, >>> "\\_SB.GPO1", 0) { >>> 14 // 14 is the GPIO pin number >>> } >>> } >>> >>> Signed-off-by: Miao Wang <[email protected]> >>> --- >>> drivers/mfd/ls2k-bmc-core.c | 162 >>> +++++++++++++++++++++++++++++++------------- >>> 1 file changed, 115 insertions(+), 47 deletions(-) >>> >>> diff --git a/drivers/mfd/ls2k-bmc-core.c b/drivers/mfd/ls2k-bmc-core.c >>> index >>> f87224105b3720cca97dcef089dad63fe57bc8c2..7187b2dfddc3acfb9fdf3cb3b4675299928dd03a >>> 100644 >>> --- a/drivers/mfd/ls2k-bmc-core.c >>> +++ b/drivers/mfd/ls2k-bmc-core.c >>> @@ -26,6 +26,9 @@ >>> #include <linux/stop_machine.h> >>> #include <linux/vt_kern.h> >>> #include <linux/console.h> >>> +#include <linux/gpio/consumer.h> >>> +#include <linux/gpio/driver.h> >>> +#include <linux/gpio.h> >> >> I've stopped here because this is a legacy header that must not be included >> and none of the interfaces in it must be used, as per the - very loud - >> comment >> at the top of that file. > > I fully understand using the legacy interface is deprecated. However, there > seems no other way to obtain a gpio line description after a gpio device > is found using gpio_device_find(). As the comment shows in the code below, > the only place I use the legacy interface is: > > gdev = gpio_device_find(...); > desc = gpio_device_get_desc(gdev, LS2K_BMC_RESET_GPIO); >
No, new code using legacy API is *not* acceptable. That's an official NAK. > // XXX: might be better to use gpiod_request() > legacy_gpio = desc_to_gpio(desc); > devm_gpio_request_one(..., legacy_gpio, ...); > return gpio_to_desc(legacy_gpio); > > I just borrowed the legacy gpio interface to request the irq description. I > think that gpiod_request() should be better to be used here, but it is not > an interface that is exposed. As a result, I post this patch as a PoC here > to discuss and find a better way to achieve this. > If the firmware doesn't describe the GPIO, you have at least two alternatives. Please look at Documentation/driver-api/gpio/legacy-boards.rst. You should be able to use either software nodes or GPIO lookup tables. This document describes the conversion from the latter to the former but - while software nodes are preferred - lookup tables are not deprecated so feel free to use it to set up the descriptors. Bart _______________________________________________ Openipmi-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openipmi-developer
