greybus-dev January 2026

greybus-dev@lists.linaro.org

16 participants
18 discussions

[PATCH 0/8] greybus: support point-to-point topology

by Damien Riégel

In a classic Greybus topology, there is an application processor, an SVC, and one or more modules, all connected to a UniPro bus. Most of the time, as the application processor doesn't have a UniPro interface, it is actually connected to a device acting as a bridge with the bus, and this bridge also acts as the SVC. Sometimes, there is no UniPro bus at all, like for the BeaglePlay, which has the following topology: +----+ +------------+ +--------+ | AP | <--- UART ---> | SVC/Bridge | <--- 802.15.4 ---> | Module | +----+ +------------+ +--------+ | | +--------+ `------------ 802.15.4 ---> | Module | +--------+ There are two main interesting aspects with Greybus: - the SVC protocol to monitor and configure the bus - other protocols, to expose module peripherals to the host When the bus has a single module connected directly to the AP, then this module must also implement the SVC protocol: +----+ +------------+ | AP | <--- bus ---> | SVC/Module | +----+ +------------+ The SVC doesn' really serve a purpose here, as there is no bus to manage, and adding its support only increase the complexity and the code size needed on memory-constrained devices. The goal of this patchset is to let a single module expose some Greybus protocols without requiring the module to also implement SVC protocol. We call this mode "Point-To-Point". There are three main notable facts with the implementation of this patchset: - most of the time, what this patchet does is just skipping calls that issue commands to the SVC, as they are not applicable without an SVC - CPort ID allocation is a bit different as there is no SVC/Bridge to do translation between AP address space and interface address space, so the patchset forces allocation of AP CPort IDs that matches the ones found in interface's manifest - enumeration of a module is normally started by a "Module Inserted" event issued by the SVC. As the SVC is absent, the host device driver must manually call a function to start the enumeration We tested this patchset with the gb-beagleplay driver, slightly tweaked to only keep the HLDC over UART part of the driver, connected over UART to an EFR32MG24 running BeagleBoard's implementation of Greybus-Zephyr [1]. In the discussion to integrate this module into Zephyr [2] (it's currently as separate module not part of the main Zephyr code base), there seems to be interest in being able to have a single-node device on the bus without SVC [3]. If some features that were implemented by the SVC are missing, we can consider adding more callbacks to the gb_hd_driver structure at a later time, and let drivers decide how they want to support these features. [1] https://github.com/beagleboard/greybus-zephyr [2] https://github.com/zephyrproject-rtos/zephyr/issues/98259 [3] https://github.com/zephyrproject-rtos/zephyr/issues/98259#issuecomment-3561… Damien Riégel (8): greybus: add P2P interface type greybus: let gb_interface_create take additional p2p argument greybus: force CPort ID allocation in P2P mode greybus: split module creation function greybus: add function create module in P2P mode greybus: make host API work without SVC greybus: add function to create SVC-less host device greybus: add function to probe p2p module drivers/greybus/connection.c | 15 ++++-- drivers/greybus/hd.c | 80 +++++++++++++++++++++++++++---- drivers/greybus/interface.c | 72 ++++++++++++++++++++-------- drivers/greybus/module.c | 55 ++++++++++++++++++--- include/linux/greybus/hd.h | 6 +++ include/linux/greybus/interface.h | 4 +- include/linux/greybus/module.h | 1 + 7 files changed, 193 insertions(+), 40 deletions(-) -- 2.49.0

3 weeks, 4 days

[PATCH v2 00/14] greybus: introduce CPC as transport layer

by Damien Riégel

Hi, This patchset brings support for Silicon Labs' CPC protocol as transport layer for Greybus. This is introduced as a module that sits between Greybus and CPC Host Device Drivers implementations, like SDIO or SPI. This patchset includes SDIO as physical layer. +----------------------------------------------------+ | Greybus | +----------------------------------------------------+ /|\ | \|/ +----------------------------------------------------+ | CPC | +----------------------------------------------------+ /|\ /|\ /|\ | | | \|/ \|/ \|/ +----------+ +---------+ +-----------+ | SDIO | | SPI | | Others | +----------+ +---------+ +-----------+ CPC implements some of the features of Unipro that Greybus relies upon, like reliable transmission. CPC takes care of detecting transmission errors and retransmit frames if necessary, but that feature is not part of the RFC to keep it concise. There's also a flow-control feature, preventing sending messages to already full cports. In order to implement these features, a 4-byte header is prepended to Greybus messages, making the whole header 12 bytes (Greybus header is 8 bytes). This RFC starts by implementing a shim layer between physical bus drivers (like SDIO and SPI) and Greybus, and progressively add more elements to it to make it useful in its own right. Finally, an SDIO driver is added to enable the communication with a remote device. Changes in v2: - addressed review comments and errors reported by kernel bot - for SDIO driver, remove padding between headers and payloads when aggregating packets together Damien Riégel (13): greybus: cpc: add minimal CPC Host Device infrastructure greybus: cpc: introduce CPC cport structure greybus: cpc: use socket buffers instead of gb_message in TX path greybus: cpc: pack cport ID in Greybus header greybus: cpc: switch RX path to socket buffers greybus: cpc: introduce CPC header structure greybus: cpc: account for CPC header size in RX and TX path greybus: cpc: add and validate sequence numbers greybus: cpc: acknowledge all incoming messages greybus: cpc: use holding queue instead of sending out immediately greybus: cpc: honour remote's RX window greybus: cpc: let host device drivers dequeue TX frames greybus: cpc: add private data pointer in CPC Host Device Gabriel Beaulieu (1): greybus: cpc: add CPC SDIO host driver MAINTAINERS | 6 + drivers/greybus/Kconfig | 2 + drivers/greybus/Makefile | 2 + drivers/greybus/cpc/Kconfig | 22 ++ drivers/greybus/cpc/Makefile | 9 + drivers/greybus/cpc/cpc.h | 75 +++++ drivers/greybus/cpc/cport.c | 112 +++++++ drivers/greybus/cpc/header.c | 136 +++++++++ drivers/greybus/cpc/header.h | 55 ++++ drivers/greybus/cpc/host.c | 313 +++++++++++++++++++ drivers/greybus/cpc/host.h | 63 ++++ drivers/greybus/cpc/protocol.c | 168 +++++++++++ drivers/greybus/cpc/sdio.c | 533 +++++++++++++++++++++++++++++++++ 13 files changed, 1496 insertions(+) create mode 100644 drivers/greybus/cpc/Kconfig create mode 100644 drivers/greybus/cpc/Makefile create mode 100644 drivers/greybus/cpc/cpc.h create mode 100644 drivers/greybus/cpc/cport.c create mode 100644 drivers/greybus/cpc/header.c create mode 100644 drivers/greybus/cpc/header.h create mode 100644 drivers/greybus/cpc/host.c create mode 100644 drivers/greybus/cpc/host.h create mode 100644 drivers/greybus/cpc/protocol.c create mode 100644 drivers/greybus/cpc/sdio.c -- 2.52.0

3 weeks, 5 days

[PATCH] staging: greybus: remove completed GPIO conversion task from TODO

by Archit Anant

The task to convert the Greybus subsystem to the GPIO descriptor interface has been completed. A grep of the directory confirms that no consumer drivers include <linux/gpio.h> or use the legacy integer based GPIO API (gpio_request, gpio_set_value, etc). Remove the stale entry from the TODO file. Signed-off-by: Archit Anant <architanant5(a)gmail.com> --- drivers/staging/greybus/TODO | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/staging/greybus/TODO b/drivers/staging/greybus/TODO index 6461e0132fe3..43fb6dc3dff0 100644 --- a/drivers/staging/greybus/TODO +++ b/drivers/staging/greybus/TODO @@ -1,5 +1,2 @@ -* Convert all uses of the old GPIO API from <linux/gpio.h> to the - GPIO descriptor API in <linux/gpio/consumer.h> and look up GPIO - lines from device tree or ACPI. * Make pwm.c use the struct pwm_ops::apply instead of ::config, ::set_polarity, ::enable and ::disable. -- 2.39.5

4 weeks, 1 day

[PATCH] staging: greybus: audio: Limit scope of jack-related variables

by Lee Yongjun

Move jack-related variable declarations inside the CONFIG_SND_JACK conditional block. These variables are only used when CONFIG_SND_JACK is enabled, so limiting their scope improves code clarity and avoids unused variable warnings when the option is disabled. No functional changes intended. Signed-off-by: Lee Yongjun <jun85566(a)gmail.com> --- drivers/staging/greybus/audio_codec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/greybus/audio_codec.c b/drivers/staging/greybus/audio_codec.c index 444c53b4e08d..f752d5fbd685 100644 --- a/drivers/staging/greybus/audio_codec.c +++ b/drivers/staging/greybus/audio_codec.c @@ -935,8 +935,6 @@ static void gbaudio_codec_cleanup(struct gbaudio_module_info *module) void gbaudio_unregister_module(struct gbaudio_module_info *module) { struct snd_soc_component *comp = gbcodec->component; - struct gbaudio_jack *jack, *n; - int mask; dev_dbg(comp->dev, "Unregister %s module\n", module->name); @@ -948,6 +946,8 @@ void gbaudio_unregister_module(struct gbaudio_module_info *module) mutex_unlock(&gbcodec->lock); #ifdef CONFIG_SND_JACK + struct gbaudio_jack *jack, *n; + int mask; /* free jack devices for this module jack_list */ list_for_each_entry_safe(jack, n, &module->jack_list, list) { if (jack == &module->headset) -- 2.34.1

1 month

[PATCH 0/1] staging: greybus: fw-core: use %pe for error printing

by Archit Anant

This patch modernizes error printing in the Greybus firmware core driver. It replaces the old 'PTR_ERR' + '%ld' pattern with the newer '%pe' format specifier, which prints error names instead of numbers, making it easy for debuging. Archit Anant (1): staging: greybus: fw-core: use %pe for error printing drivers/staging/greybus/fw-core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) -- 2.39.5

1 month

[PATCH] staging: greybus: arche: drop dangling Kconfig symbol

by Randy Dunlap

The Kconfig symbol USB_HSIC_USB3613 is not defined in the kernel source tree. Drop it since it unused. Fixes: 2eccd4aa19fc ("staging: greybus: enable compile testing of arche driver") Signed-off-by: Randy Dunlap <rdunlap(a)infradead.org> --- Cc: Vaibhav Hiremath <hvaibhav.linux(a)gmail.com> Cc: Johan Hovold <johan(a)kernel.org> Cc: Alex Elder <elder(a)kernel.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: greybus-dev(a)lists.linaro.org Cc: linux-staging(a)lists.linux.dev drivers/staging/greybus/Kconfig | 1 - drivers/staging/greybus/arche-platform.c | 4 ---- 2 files changed, 5 deletions(-) --- linux-next-20251219.orig/drivers/staging/greybus/arche-platform.c +++ linux-next-20251219/drivers/staging/greybus/arche-platform.c @@ -23,14 +23,10 @@ #include <linux/of.h> #include "arche_platform.h" -#if IS_ENABLED(CONFIG_USB_HSIC_USB3613) -#include <linux/usb/usb3613.h> -#else static inline int usb3613_hub_mode_ctrl(bool unused) { return 0; } -#endif #define WD_COLDBOOT_PULSE_WIDTH_MS 30 --- linux-next-20251219.orig/drivers/staging/greybus/Kconfig +++ linux-next-20251219/drivers/staging/greybus/Kconfig @@ -206,7 +206,6 @@ endif # GREYBUS_BRIDGED_PHY config GREYBUS_ARCHE tristate "Greybus Arche Platform driver" - depends on USB_HSIC_USB3613 || COMPILE_TEST help Select this option if you have an Arche device.

1 month

[PATCH v2] greybus: Use bus methods for .probe() and .remove()

by Uwe Kleine-König

These are nearly identical to the respective driver callbacks. The only difference is that .remove() returns void instead of int. The objective is to get rid of users of struct device_driver callbacks .probe() and .remove() to eventually remove these. Acked-by: Johan Hovold <johan(a)kernel.org> Signed-off-by: Uwe Kleine-König <u.kleine-koenig(a)baylibre.com> --- Changes since (implicit) v1, https://lore.kernel.org/greybus-dev/20251210175943.590059-2-u.kleine-koenig…: - keep tabs in the struct initializer - Add Ack by Johan drivers/greybus/core.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/drivers/greybus/core.c b/drivers/greybus/core.c index 313eb65cf703..45c5437c460f 100644 --- a/drivers/greybus/core.c +++ b/drivers/greybus/core.c @@ -185,13 +185,6 @@ static void greybus_shutdown(struct device *dev) } } -const struct bus_type greybus_bus_type = { - .name = "greybus", - .match = greybus_match_device, - .uevent = greybus_uevent, - .shutdown = greybus_shutdown, -}; - static int greybus_probe(struct device *dev) { struct greybus_driver *driver = to_greybus_driver(dev->driver); @@ -252,7 +245,7 @@ static int greybus_probe(struct device *dev) return 0; } -static int greybus_remove(struct device *dev) +static void greybus_remove(struct device *dev) { struct greybus_driver *driver = to_greybus_driver(dev->driver); struct gb_bundle *bundle = to_gb_bundle(dev); @@ -291,10 +284,17 @@ static int greybus_remove(struct device *dev) pm_runtime_set_suspended(dev); pm_runtime_dont_use_autosuspend(dev); pm_runtime_put_noidle(dev); - - return 0; } +const struct bus_type greybus_bus_type = { + .name = "greybus", + .match = greybus_match_device, + .uevent = greybus_uevent, + .probe = greybus_probe, + .remove = greybus_remove, + .shutdown = greybus_shutdown, +}; + int greybus_register_driver(struct greybus_driver *driver, struct module *owner, const char *mod_name) { @@ -305,8 +305,6 @@ int greybus_register_driver(struct greybus_driver *driver, struct module *owner, driver->driver.bus = &greybus_bus_type; driver->driver.name = driver->name; - driver->driver.probe = greybus_probe; - driver->driver.remove = greybus_remove; driver->driver.owner = owner; driver->driver.mod_name = mod_name; base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8 -- 2.47.3

1 month, 1 week

[PATCH] staging: greybus: add WQ_PERCPU to alloc_workqueue users

by marco.crivellari＠suse.com

The content of this message was lost. It was probably cross-posted to multiple lists and previously handled on another list.

1 month, 1 week

[PATCH] greybus: Use bus methods for .probe() and .remove()

by Uwe Kleine-König

These are nearly identical to the respective driver callbacks. The only difference is that .remove() returns void instead of int. The objective is to get rid of users of struct device_driver callbacks .probe() and .remove() to eventually remove these. Signed-off-by: Uwe Kleine-König <u.kleine-koenig(a)baylibre.com> --- drivers/greybus/core.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/drivers/greybus/core.c b/drivers/greybus/core.c index 313eb65cf703..927a69feb3fc 100644 --- a/drivers/greybus/core.c +++ b/drivers/greybus/core.c @@ -185,13 +185,6 @@ static void greybus_shutdown(struct device *dev) } } -const struct bus_type greybus_bus_type = { - .name = "greybus", - .match = greybus_match_device, - .uevent = greybus_uevent, - .shutdown = greybus_shutdown, -}; - static int greybus_probe(struct device *dev) { struct greybus_driver *driver = to_greybus_driver(dev->driver); @@ -252,7 +245,7 @@ static int greybus_probe(struct device *dev) return 0; } -static int greybus_remove(struct device *dev) +static void greybus_remove(struct device *dev) { struct greybus_driver *driver = to_greybus_driver(dev->driver); struct gb_bundle *bundle = to_gb_bundle(dev); @@ -291,10 +284,17 @@ static int greybus_remove(struct device *dev) pm_runtime_set_suspended(dev); pm_runtime_dont_use_autosuspend(dev); pm_runtime_put_noidle(dev); - - return 0; } +const struct bus_type greybus_bus_type = { + .name = "greybus", + .match = greybus_match_device, + .uevent = greybus_uevent, + .probe = greybus_probe, + .remove = greybus_remove, + .shutdown = greybus_shutdown, +}; + int greybus_register_driver(struct greybus_driver *driver, struct module *owner, const char *mod_name) { @@ -305,8 +305,6 @@ int greybus_register_driver(struct greybus_driver *driver, struct module *owner, driver->driver.bus = &greybus_bus_type; driver->driver.name = driver->name; - driver->driver.probe = greybus_probe; - driver->driver.remove = greybus_remove; driver->driver.owner = owner; driver->driver.mod_name = mod_name; base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449 -- 2.47.3

1 month, 1 week

[PATCH v2] greybus: add WQ_PERCPU to alloc_workqueue users

by Marco Crivellari

This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") This change adds a new WQ_PERCPU flag to explicitly request alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. Once migration is complete, WQ_UNBOUND can be removed and unbound will become the implicit default. Suggested-by: Tejun Heo <tj(a)kernel.org> Signed-off-by: Marco Crivellari <marco.crivellari(a)suse.com> Reviewed-by: Johan Hovold <johan(a)kernel.org> --- Changes in v2: - updated commit log removing two paragraph not strictly related to the work. - subject changed removing "drivers/" before the actual prefix. --- drivers/greybus/operation.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/greybus/operation.c b/drivers/greybus/operation.c index 54ccc434a1f7..7e12ffb2dd60 100644 --- a/drivers/greybus/operation.c +++ b/drivers/greybus/operation.c @@ -1238,7 +1238,7 @@ int __init gb_operation_init(void) goto err_destroy_message_cache; gb_operation_completion_wq = alloc_workqueue("greybus_completion", - 0, 0); + WQ_PERCPU, 0); if (!gb_operation_completion_wq) goto err_destroy_operation_cache; -- 2.51.1

1 month, 1 week

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greybus-dev January 2026