kernel/linux.git/drivers/i2c/Makefile, branch v6.18.21

i2c: Introduce OF component probe function

2024-11-27T11:04:10+00:00

Some devices are designed and manufactured with some components having multiple drop-in replacement options. These components are often connected to the mainboard via ribbon cables, having the same signals and pin assignments across all options. These may include the display panel and touchscreen on laptops and tablets, and the trackpad on laptops. Sometimes which component option is used in a particular device can be detected by some firmware provided identifier, other times that information is not available, and the kernel has to try to probe each device. This change attempts to make the "probe each device" case cleaner. The current approach is to have all options added and enabled in the device tree. The kernel would then bind each device and run each driver's probe function. This works, but has been broken before due to the introduction of asynchronous probing, causing multiple instances requesting "shared" resources, such as pinmuxes, GPIO pins, interrupt lines, at the same time, with only one instance succeeding. Work arounds for these include moving the pinmux to the parent I2C controller, using GPIO hogs or pinmux settings to keep the GPIO pins in some fixed configuration, and requesting the interrupt line very late. Such configurations can be seen on the MT8183 Krane Chromebook tablets, and the Qualcomm sc8280xp-based Lenovo Thinkpad 13S. Instead of this delicate dance between drivers and device tree quirks, this change introduces a simple I2C component probe function. For a given class of devices on the same I2C bus, it will go through all of them, doing a simple I2C read transfer and see which one of them responds. It will then enable the device that responds. This requires some minor modifications in the existing device tree. The status for all the device nodes for the component options must be set to "fail-needs-probe". This makes it clear that some mechanism is needed to enable one of them, and also prevents the prober and device drivers running at the same time. Signed-off-by: Chen-Yu Tsai Reviewed-by: Andy Shevchenko Reviewed-by: Douglas Anderson Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Wolfram Sang

i2c: Use -y instead of -objs in Makefile

2024-11-04T11:01:51+00:00

*-objs suffix is reserved rather for (user-space) host programs while usually *-y suffix is used for kernel drivers (although *-objs works for that purpose for now). Let's correct the old usages of *-objs in Makefiles. Signed-off-by: Andy Shevchenko Signed-off-by: Wolfram Sang

i2c: core: Remove extra space in Makefile

2024-10-08T09:04:23+00:00

Some lines in the Makefile have a space before tabs. Remove those. Reported-by: Andy Shevchenko Closes: https://lore.kernel.org/all/ZsdE0PxKnGRjzChl@smile.fi.intel.com/ Signed-off-by: Chen-Yu Tsai Reviewed-by: Andy Shevchenko Reviewed-by: Andi Shyti Signed-off-by: Wolfram Sang

media: i2c: add I2C Address Translator (ATR) support

2023-07-14T11:11:44+00:00

An ATR is a device that looks similar to an i2c-mux: it has an I2C slave "upstream" port and N master "downstream" ports, and forwards transactions from upstream to the appropriate downstream port. But it is different in that the forwarded transaction has a different slave address. The address used on the upstream bus is called the "alias" and is (potentially) different from the physical slave address of the downstream chip. Add a helper file (just like i2c-mux.c for a mux or switch) to allow implementing ATR features in a device driver. The helper takes care of adapter creation/destruction and translates addresses at each transaction. Signed-off-by: Luca Ceresoli Signed-off-by: Tomi Valkeinen Reviewed-by: Andy Shevchenko Acked-by: Wolfram Sang Signed-off-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab

i2c: add slave testunit driver

2020-09-21T09:02:17+00:00

Here is an I2C slave backend driver which allows to test some uncommon functionalities of the I2C and SMBus world. Usually, you need specific devices to test e.g. SMBus Host Notify and such. With this driver you just need the slave interface of another I2C controller. This initial version has testcases for multi-master and SMBus Host Notify. Already planned but not yet implemented are SMBus Alert and messages with I2C_M_RECV_LEN. Please read the documentation for further details. Signed-off-by: Wolfram Sang Signed-off-by: Wolfram Sang

i2c: don't use any __deprecated handling anymore

2018-08-24T15:26:43+00:00

This can be dropped with commit 771c035372a036f83353eef46dbb829780330234 ("deprecate the '__deprecated' attribute warnings entirely and for good") now in upstream. And we got rid of the last __deprecated use, too. Signed-off-by: Sedat Dilek [wsa: shortened commit message to reflect the current situation] Signed-off-by: Wolfram Sang

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

i2c: break out ACPI support into separate file

2017-05-31T19:01:04+00:00

Removes some ifdeffery. Also add the new file to the relevant MAINTAINERS section. Reviewed-by: Mika Westerberg Reviewed-by: Andy Shevchenko Signed-off-by: Wolfram Sang

i2c: break out OF support into separate file