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mfd: cros_ec: spi: Increase cros_ec_spi deadline from 5ms to 100ms

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We're adding i2c tunneling to the list of things that goes over
cros_ec.  i2c tunneling can be slooooooow, so increase our deadline to
100ms to account for that.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Andrew Bresticker <abrestic@chromium.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Doug Anderson 2014-04-30 10:44:07 -07:00 committed by Lee Jones
parent c9a81d67ce
commit 9c0b54a120
1 changed files with 16 additions and 8 deletions
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24
drivers/mfd/cros_ec_spi.c
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@ -39,14 +39,22 @@
#define EC_MSG_PREAMBLE_COUNT 32
/*
* We must get a response from the EC in 5ms. This is a very long
* time, but the flash write command can take 2-3ms. The EC command
* processing is currently not very fast (about 500us). We could
* look at speeding this up and making the flash write command a
* 'slow' command, requiring a GET_STATUS wait loop, like flash
* erase.
*/
#define EC_MSG_DEADLINE_MS 5
* Allow for a long time for the EC to respond. We support i2c
* tunneling and support fairly long messages for the tunnel (249
* bytes long at the moment). If we're talking to a 100 kHz device
* on the other end and need to transfer ~256 bytes, then we need:
* 10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms
*
* We'll wait 4 times that to handle clock stretching and other
* paranoia.
*
* It's pretty unlikely that we'll really see a 249 byte tunnel in
* anything other than testing. If this was more common we might
* consider having slow commands like this require a GET_STATUS
* wait loop. The 'flash write' command would be another candidate
* for this, clocking in at 2-3ms.
*/
#define EC_MSG_DEADLINE_MS 100
/*
* Time between raising the SPI chip select (for the end of a