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path: root/src/include/device/i2c.h
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2014-12-30i2c: Add software_i2c driver for I2C debugging and emulationJulius Werner
This patch adds I2C emulation in software through raw toggling of the SDA/SCL lines. Platforms need to provide bindings to toggle their respective I2C busses for this to work (e.g. by pinmuxing them as GPIOs, currently only enabled for Tegra). This is mostly useful as a debugging feature, to drive unusual states on a bus and closely monitor the device output without the need of a bus analyzer. It provides a few functions to "wedge" an I2C bus by aborting a transaction at certain points, which can be used to test if a system can correctly recover from an ill-timed reboot. However, it can also dynamically replace the existing I2C transfer functions and drive some/all I2C transfers on the system, which might be useful if a driver for the actual I2C controller hardware is not (yet) available. Based on original code by Doug Anderson <dianders@chromium.org> and Hung-ying Tyan <tyanh@chromium.org> for the ChromeOS embedded controller project. BRANCH=None BUG=chrome-os-partner:28323 TEST=Spread tegra_software_i2c_init()/tegra_software_i2c_disable() through the code and see that everything still works. Original-Change-Id: I9ee7ccbd1efb38206669a35d0c3318af16f8be63 Original-Signed-off-by: Julius Werner <jwerner@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/198791 Original-Reviewed-by: Doug Anderson <dianders@chromium.org> Original-Reviewed-by: Tom Warren <twarren@nvidia.com> Original-Reviewed-by: Stefan Reinauer <reinauer@chromium.org> (cherry picked from commit 8f71503dbbd74c5298e90e2163b67d4efe3e89db) Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: Id6c5f75bb5baaabd62b6b1fc26c2c71d9f1ce682 Reviewed-on: http://review.coreboot.org/7947 Tested-by: build bot (Jenkins) Reviewed-by: David Hendricks <dhendrix@chromium.org>
2014-12-16i2c: Replace the i2c API.Gabe Black
The new API is in use in depthcharge and is based around the "i2c_transfer" function instead of i2c_read and i2c_write. The new function takes an array of i2c_seg structures which represent each portion of the transfer after a start bit and before the stop bit. If there's more than one segment, they're seperated by repeated starts. Some wrapper functions have also been added which make certain common operations easy. These include reading or writing a byte from a register or reading or writing a blob of raw data. The i2c device drivers generally use these wrappers but can call the i2c_transfer function directly if the need something different. The tegra i2c driver was very similar to the one in depthcharge and was simple to convert. The Exynos 5250 and 5420 drivers were ported from depthcharge and replace the ones in coreboot. The Exynos 5420 driver was ported from the high speed portion of the one in coreboot and was straightforward to port back. The low speed portion and the Exynos 5250 drivers had been transplanted from U-Boot and were replaced with the depthcharge implementation. BUG=None TEST=Built and booted on nyan with and without EFS. Built and booted on, pit and daisy. BRANCH=None Original-Change-Id: I1e98c3fa2560be25444ab3d0394bb214b9d56e93 Original-Signed-off-by: Gabe Black <gabeblack@google.com> Original-Reviewed-on: https://chromium-review.googlesource.com/193561 Original-Reviewed-by: David Hendricks <dhendrix@chromium.org> Original-Reviewed-by: Jimmy Zhang <jimmzhang@nvidia.com> Original-Tested-by: Jimmy Zhang <jimmzhang@nvidia.com> Original-Reviewed-by: Hung-Te Lin <hungte@chromium.org> Original-Commit-Queue: Gabe Black <gabeblack@chromium.org> Original-Tested-by: Gabe Black <gabeblack@chromium.org> (cherry picked from commit 00c423fb2c06c69d580ee3ec0a3892ebf164a5fe) This cherry-pick required additional changes to the following: src/cpu/allwinner/a10/twi.c src/drivers/xpowers/axp209/axp209.c Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: I691959c66308eeeec219b1bec463b8b365a246d7 Reviewed-on: http://review.coreboot.org/7751 Tested-by: build bot (Jenkins) Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com> Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2013-07-10i2c: Change the type of the data parameter to uint8_t.Gabe Black
Data is intended to be a byte array, so it should be described by a type which has a fixed size equal to an 8 bit byte. Also, the data passed to write shouldn't be modified and can be const. Change-Id: I6466303d962998f6c37c2d4006a39c2d79a235c1 Signed-off-by: Gabe Black <gabeblack@chromium.org> Reviewed-on: http://review.coreboot.org/3721 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2013-04-09replace device/i2c.h with simpler versionDavid Hendricks
The existing header was imported along with the Exynos code and left mostly unchanged. This is the first patch in a series intended to replace the imported u-boot I2C API with a much simpler and cleaner interface: - We only need to expose i2c_read() and i2c_write() in our public API. Everything else is board/chip-dependent and should remain hidden away. - i2c_read and i2c_write functions will take bus number as an arg and we'll eliminate i2c_get_bus and i2c_set_bus. Those are prone to error and end up cluttering the code since the user needs to save the old bus number, set the new one, do the read/write, and restore the old value (3 added steps to do a simple transaction). - Stop setting default values for board-specific things like SPD and RTC bus numbers (as if we always have an SPD or RTC on I2C). - Death to all the trivial inline wrappers. And in case there was any doubt, we really don't care about the MPC8xx. Though if we did then we would not pollute the public API with its idiosyncrasies. Change-Id: I4410a3c82ed5a6b2e80e3d8c0163464a9ca7c3b0 Signed-off-by: David Hendricks <dhendrix@chromium.org> Reviewed-on: http://review.coreboot.org/3043 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2013-02-06replace uchar and uint with standard types in generic i2c headerDavid Hendricks
Change-Id: Ie72985bb5291bcef2e837a2f4f2ec929a0c086ce Signed-off-by: David Hendricks <dhendrix@chromium.org> Reviewed-on: http://review.coreboot.org/2290 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
2012-12-29import i2c header from u-bootDavid Hendricks
This just imports a header. We may wish to modify the i2c interface and/or unify it with the smbus interface we currently have. Change-Id: I314f3aef62be936456c6c3e164a3db2c473b8792 Signed-off-by: David Hendricks <dhendrix@chromium.org> Reviewed-on: http://review.coreboot.org/2079 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>