kernel/linux.git/drivers/tty/serdev/core.c, branch v6.19.11

serdev: Drop dev_pm_domain_detach() call

2025-09-06T13:48:38+00:00

Starting with commit f99508074e78 ("PM: domains: Detach on device_unbind_cleanup()"), there is no longer a need to call dev_pm_domain_detach() in the bus remove function. The device_unbind_cleanup() function now handles this to avoid invoking devres cleanup handlers while the PM domain is powered off, which could otherwise lead to failures as described in the above-mentioned commit. Drop the explicit dev_pm_domain_detach() call and rely instead on the flags passed to dev_pm_domain_attach() to power off the domain. Signed-off-by: Claudiu Beznea Reviewed-by: Ulf Hansson Link: https://lore.kernel.org/r/20250827101747.928265-1-claudiu.beznea.uj@bp.renesas.com Signed-off-by: Greg Kroah-Hartman

PM: domains: Add flags to specify power on attach/detach

2025-07-07T18:41:20+00:00

Calling dev_pm_domain_attach()/dev_pm_domain_detach() in bus driver probe/remove functions can affect system behavior when the drivers attached to the bus use devres-managed resources. Since devres actions may need to access device registers, calling dev_pm_domain_detach() too early, i.e., before these actions complete, can cause failures on some systems. One such example is Renesas RZ/G3S SoC-based platforms. If the device clocks are managed via PM domains, invoking dev_pm_domain_detach() in the bus driver's remove function removes the device's clocks from the PM domain, preventing any subsequent pm_runtime_resume*() calls from enabling those clocks. The second argument of dev_pm_domain_attach() specifies whether the PM domain should be powered on during attachment. Likewise, the second argument of dev_pm_domain_detach() indicates whether the domain should be powered off during detachment. Upcoming changes address the issue described above (initially for the platform bus only) by deferring the call to dev_pm_domain_detach() until after devres_release_all() in device_unbind_cleanup(). The detach_power_off field in struct dev_pm_info stores the detach power off info from the second argument of dev_pm_domain_attach(). Because there are cases where the device's PM domain power-on/off behavior must be conditional (e.g., in i2c_device_probe()), the patch introduces PD_FLAG_ATTACH_POWER_ON and PD_FLAG_DETACH_POWER_OFF flags to be passed to dev_pm_domain_attach(). Finally, dev_pm_domain_attach() and its users are updated to use the newly introduced PD_FLAG_ATTACH_POWER_ON and PD_FLAG_DETACH_POWER_OFF macros. This change is preparatory. Signed-off-by: Claudiu Beznea Reviewed-by: Mathieu Poirier Acked-by: Wolfram Sang # I2C Reviewed-by: Ulf Hansson Link: https://patch.msgid.link/20250703112708.1621607-2-claudiu.beznea.uj@bp.renesas.com [ rjw: Changelog adjustments ] Signed-off-by: Rafael J. Wysocki

serdev: Refine several error or debug messages

2025-05-01T15:20:49+00:00

Refine several dev_err() and dev_dbg() messages to solve: // hardcoded device name dev_dbg(dev, "...dev_name_str...") // repeated device name since dev_dbg() also prints it as prefix dev_err(dev, "...%s...", dev_name(dev)) // not concise as dev_err(dev, "...%d...", err) dev_err(dev, "...%pe...", ERR_PTR(err)) Signed-off-by: Zijun Hu Reviewed-by: Jiri Slaby Link: https://lore.kernel.org/r/20250425-fix_serdev-v3-1-2e4ea8261640@quicinc.com Signed-off-by: Greg Kroah-Hartman

tty: serdev: drop serdev_controller_ops::write_room()

2025-03-20T15:00:51+00:00

In particular, serdev_device_write_room() is not called, so the whole serdev's write_room() can go. Signed-off-by: Jiri Slaby (SUSE) Cc: Rob Herring Link: https://lore.kernel.org/r/20250317070046.24386-17-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

serdev: Use of_property_present()

2024-08-07T11:08:14+00:00

Use of_property_present() to test for property presence rather than of_get_property(). This is part of a larger effort to remove callers of of_get_property() and similar functions. of_get_property() leaks the DT property data pointer which is a problem for dynamically allocated nodes which may be freed. Signed-off-by: Rob Herring (Arm) Link: https://lore.kernel.org/r/20240731191312.1710417-17-robh@kernel.org Signed-off-by: Greg Kroah-Hartman

driver core: have match() callback in struct bus_type take a const *

2024-07-03T13:16:54+00:00

In the match() callback, the struct device_driver * should not be changed, so change the function callback to be a const *. This is one step of many towards making the driver core safe to have struct device_driver in read-only memory. Because the match() callback is in all busses, all busses are modified to handle this properly. This does entail switching some container_of() calls to container_of_const() to properly handle the constant *. For some busses, like PCI and USB and HV, the const * is cast away in the match callback as those busses do want to modify those structures at this point in time (they have a local lock in the driver structure.) That will have to be changed in the future if they wish to have their struct device * in read-only-memory. Cc: Rafael J. Wysocki Reviewed-by: Alex Elder Acked-by: Sumit Garg Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh Signed-off-by: Greg Kroah-Hartman

serdev: make serdev_bus_type const

2024-02-06T14:35:38+00:00

Now that the driver core can properly handle constant struct bus_type, move the serdev_bus_type variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Suggested-by: Greg Kroah-Hartman Signed-off-by: "Ricardo B. Marliere" Link: https://lore.kernel.org/r/20240203-bus_cleanup-tty-v1-1-86b698c82efe@marliere.net Signed-off-by: Greg Kroah-Hartman

serdev: Remove usage of the deprecated ida_simple_xx() API

2023-12-15T13:20:06+00:00

ida_alloc() and ida_free() should be preferred to the deprecated ida_simple_get() and ida_simple_remove(). This is less verbose. Signed-off-by: Christophe JAILLET Link: https://lore.kernel.org/r/d20d3ac106bac6b7cabe39f22ad00ac86910e0a5.1702230342.git.christophe.jaillet@wanadoo.fr Signed-off-by: Greg Kroah-Hartman

tty: serdev: convert to u8 and size_t

2023-12-08T11:02:38+00:00

Switch character types to u8 and sizes to size_t. To conform to characters/sizes in the rest of the tty layer. This patch converts struct serdev_device_ops hooks and its instantiations. Signed-off-by: "Jiri Slaby (SUSE)" Cc: Rob Herring Acked-by: Johan Hovold Link: https://lore.kernel.org/r/20231206073712.17776-24-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: core: Move tty and serdev to be children of serial core port device

2023-11-25T07:23:16+00:00

Let's move tty and serdev controller to be children of the serial core port device. This way the runtime PM usage count of a child device propagates to the serial hardware device. The tty and serdev devices are associated with a specific serial port of a serial hardware controller device, and we now have serial core hierarchy of controllers and ports. The tty device moves happily with just a change of the parent device and update of device_find_child() handling. The serdev device init needs some changes to separate the serial hardware controller device from the parent device. With this change the tty devices move under sysfs similar to this x86_64 qemu example of a diff of "find /sys -name ttyS*": /sys/class/tty/ttyS0 /sys/class/tty/ttyS3 /sys/class/tty/ttyS1 -/sys/devices/pnp0/00:04/tty/ttyS0 -/sys/devices/platform/serial8250/tty/ttyS2 -/sys/devices/platform/serial8250/tty/ttyS3 -/sys/devices/platform/serial8250/tty/ttyS1 +/sys/devices/pnp0/00:04/00:04:0/00:04:0.0/tty/ttyS0 +/sys/devices/platform/serial8250/serial8250:0/serial8250:0.3/tty/ttyS3 +/sys/devices/platform/serial8250/serial8250:0/serial8250:0.1/tty/ttyS1 +/sys/devices/platform/serial8250/serial8250:0/serial8250:0.2/tty/ttyS2 If a serdev device is used instead of a tty, it moves in a similar way. Suggested-by: Johan Hovold Cc: Maximilian Luz Cc: Rob Herring Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20231113080758.30346-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman