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| author | Grygorii Strashko <grygorii.strashko@ti.com> | 2015-04-06 15:38:41 +0300 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2015-04-10 18:57:28 +0300 |
| commit | 7ef97e9a312c359a2b32a7b5d918c60f238b69b2 (patch) | |
| tree | b0d9ee4ee17e5f7cbc99431701eb519aba7dc986 /Documentation/devicetree | |
| parent | 2e65676f710e8feb9f76a7beee649b0e5ff95ca3 (diff) | |
| download | linux-7ef97e9a312c359a2b32a7b5d918c60f238b69b2.tar.xz | |
i2c: davinci: use ICPFUNC to toggle I2C as gpio for bus recovery
Having a board where the I2C bus locks up occasionally made it clear
that the bus recovery in the i2c-davinci driver will only work on
some boards, because on regular boards, this will only toggle GPIO
lines that aren't muxed to the actual pins.
The I2C controller on SoCs like da850 (and da830), Keystone 2 has the
built-in capability to bit-bang its lines by using the ICPFUNC registers
of the i2c controller.
Implement the suggested procedure by toggling SCL and checking SDA using
the ICPFUNC registers of the I2C controller when present. Allow platforms
to indicate the presence of the ICPFUNC registers with a has_pfunc platform
data flag and add optional DT property "ti,has-pfunc" to indicate
the same in DT.
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Tested-by: Michael Lawnick <michael.lawnick@nokia.com>
Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca>
Signed-off-by: Mike Looijmans <milo-software@users.sourceforge.net>
[grygorii.strashko@ti.com: combined patches from Ben Gardiner and
Mike Looijmans and reimplemented ICPFUNC bus recovery using I2C
bus recovery infrastructure]
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'Documentation/devicetree')
| -rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-davinci.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-davinci.txt b/Documentation/devicetree/bindings/i2c/i2c-davinci.txt index 2dc935b4113d..a4e1cbc810c1 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-davinci.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-davinci.txt @@ -10,6 +10,9 @@ Required properties: Recommended properties : - interrupts : standard interrupt property. - clock-frequency : desired I2C bus clock frequency in Hz. +- ti,has-pfunc: boolean; if defined, it indicates that SoC supports PFUNC + registers. PFUNC registers allow to switch I2C pins to function as + GPIOs, so they can by toggled manually. Example (enbw_cmc board): i2c@1c22000 { |