[PATCH v2 0/3] PCIe Enclosure LED Management

Mariusz Tkaczyk
2024-05-28T13:19:53Z

Patchset is named as PCIe Enclosure LED Management because it adds two features:
- Native PCIe Enclosure Management (NPEM)
- PCIe SSD Status LED Management (DSM)

Both are pattern oriented standards, they tell which "indication" should blink.
It doesn't control physical LED or pattern visualization.

Overall, driver is simple but it was not simple to fit it into interfaces
we have in kernel (We considered leds and enclosure interfaces). It reuses
leds interface, this approach seems to be the best because:
- leds are actively maintained, no new interface added.
- leds do not require any extensions, enclosure needs to be adjusted first.

There are trade-offs:
- "brightness" is the name of sysfs file to control led. It is not
natural to use brightness to set patterns, that is why multiple led
devices are created (one per indication);
- Update of one led may affect other leds, led triggers may not work
as expected.

This patchset was made in close collaboration with Lucas Wunner.

Before it can be merged, DSM tests are needed.
Stuart, please test it and let us know.

Changes from v1:
- Renamed "pattern" to indication.
- DSM support added (not tested yet!).
- fixed nits reported by Bjorn.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ilpo Jarvinen <ilpo.jarvinen@linux.intel.com>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Marek Behun <marek.behun@nic.cz>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
Link: https://lore.kernel.org/linux-pci/20240215142345.6073-1-mariusz.tkaczyk@linux.intel.com/

Mariusz Tkaczyk (3):
leds: Init leds class earlier
PCI/NPEM: Add Native PCIe Enclosure Management support
PCI/NPEM: Add _DSM PCIe SSD status LED management

drivers/leds/led-class.c | 2 +-
drivers/pci/Kconfig | 9 +
drivers/pci/Makefile | 1 +
drivers/pci/npem.c | 551 ++++++++++++++++++++++++++++++++++
drivers/pci/pci.h | 8 +
drivers/pci/probe.c | 2 +
drivers/pci/remove.c | 2 +
include/linux/pci.h | 3 +
include/uapi/linux/pci_regs.h | 34 +++
9 files changed, 611 insertions(+), 1 deletion(-)
create mode 100644 drivers/pci/npem.c

--
2.35.3