diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /Documentation/driver-api/sm501.rst | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'Documentation/driver-api/sm501.rst')
| -rw-r--r-- | Documentation/driver-api/sm501.rst | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/driver-api/sm501.rst b/Documentation/driver-api/sm501.rst new file mode 100644 index 000000000..882507453 --- /dev/null +++ b/Documentation/driver-api/sm501.rst @@ -0,0 +1,74 @@ +.. include:: <isonum.txt> + +============ +SM501 Driver +============ + +:Copyright: |copy| 2006, 2007 Simtec Electronics + +The Silicon Motion SM501 multimedia companion chip is a multifunction device +which may provide numerous interfaces including USB host controller USB gadget, +asynchronous serial ports, audio functions, and a dual display video interface. +The device may be connected by PCI or local bus with varying functions enabled. + +Core +---- + +The core driver in drivers/mfd provides common services for the +drivers which manage the specific hardware blocks. These services +include locking for common registers, clock control and resource +management. + +The core registers drivers for both PCI and generic bus based +chips via the platform device and driver system. + +On detection of a device, the core initialises the chip (which may +be specified by the platform data) and then exports the selected +peripheral set as platform devices for the specific drivers. + +The core re-uses the platform device system as the platform device +system provides enough features to support the drivers without the +need to create a new bus-type and the associated code to go with it. + + +Resources +--------- + +Each peripheral has a view of the device which is implicitly narrowed to +the specific set of resources that peripheral requires in order to +function correctly. + +The centralised memory allocation allows the driver to ensure that the +maximum possible resource allocation can be made to the video subsystem +as this is by-far the most resource-sensitive of the on-chip functions. + +The primary issue with memory allocation is that of moving the video +buffers once a display mode is chosen. Indeed when a video mode change +occurs the memory footprint of the video subsystem changes. + +Since video memory is difficult to move without changing the display +(unless sufficient contiguous memory can be provided for the old and new +modes simultaneously) the video driver fully utilises the memory area +given to it by aligning fb0 to the start of the area and fb1 to the end +of it. Any memory left over in the middle is used for the acceleration +functions, which are transient and thus their location is less critical +as it can be moved. + + +Configuration +------------- + +The platform device driver uses a set of platform data to pass +configurations through to the core and the subsidiary drivers +so that there can be support for more than one system carrying +an SM501 built into a single kernel image. + +The PCI driver assumes that the PCI card behaves as per the Silicon +Motion reference design. + +There is an errata (AB-5) affecting the selection of the +of the M1XCLK and M1CLK frequencies. These two clocks +must be sourced from the same PLL, although they can then +be divided down individually. If this is not set, then SM501 may +lock and hang the whole system. The driver will refuse to +attach if the PLL selection is different. |
