diff options
| author | Philip Rakity <prakity@marvell.com> | 2011-07-06 08:51:32 -0700 |
|---|---|---|
| committer | Robert Marklund <robert.marklund@stericsson.com> | 2011-10-05 12:56:53 +0200 |
| commit | 26198b438c87e65472bff0cacdae24a5329e6ebf (patch) | |
| tree | 0138ee12f8c38a031db1e3a3d28479693780d4dd /include | |
| parent | caf8ad731faaab78d34149bf9f0f31798de81cde (diff) | |
mmc: core: Set non-default Drive Strength via platform hook
Non default Drive Strength cannot be set automatically. It is a function
of the board design and only if there is a specific platform handler can
it be set. The platform handler needs to take into account the board
design. Pass to the platform code the necessary information.
For example: The card and host controller may indicate they support HIGH
and LOW drive strength. There is no way to know what should be chosen
without specific board knowledge. Setting HIGH may lead to reflections
and setting LOW may not suffice. There is no mechanism (like ethernet
duplex or speed pulses) to determine what should be done automatically.
If no platform handler is defined -- use the default value.
Signed-off-by: Philip Rakity <prakity@marvell.com>
Reviewed-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Change-Id: I6bf5643686cf2011df25f353d0e705f6701b51c4
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/30687
Reviewed-by: Ulf HANSSON <ulf.hansson@stericsson.com>
Tested-by: Ulf HANSSON <ulf.hansson@stericsson.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mmc/host.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 18474502634..02c97d30b28 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -148,6 +148,7 @@ struct mmc_host_ops { int (*start_signal_voltage_switch)(struct mmc_host *host, struct mmc_ios *ios); int (*execute_tuning)(struct mmc_host *host); void (*enable_preset_value)(struct mmc_host *host, bool enable); + int (*select_drive_strength)(unsigned int max_dtr, int host_drv, int card_drv); }; struct mmc_card; |