diff options
| author | Sascha Hauer | 2014-08-19 10:45:51 +0200 |
|---|---|---|
| committer | Ulf Hansson | 2014-09-09 13:59:07 +0200 |
| commit | 3d705d14fe4c72be83bae1610680e209ee226b9d (patch) | |
| tree | f62e06a2feffe512962cf2ec00baccf52460cdbf /include/linux/mmc/host.h | |
| parent | mmc: sdhci-pxav3: set_uhs_signaling is initialized twice differently (diff) | |
| download | kernel-qcow2-linux-3d705d14fe4c72be83bae1610680e209ee226b9d.tar.gz kernel-qcow2-linux-3d705d14fe4c72be83bae1610680e209ee226b9d.tar.xz kernel-qcow2-linux-3d705d14fe4c72be83bae1610680e209ee226b9d.zip | |
mmc: implement Driver Stage Register handling
Some eMMC and SD cards implement a DSR register that allows to tune
raise/fall times and drive strength of the CMD and DATA outputs.
The values to use depend on the card in use and the host.
It might be needed to reduce the drive strength to prevent voltage peaks
above the host's specification.
Implement a 'dsr' devicetree property that allows to specify the value
to set the DSR to. For non-dt setups the new members of mmc_host can be
set by board code.
This patch was initially authored by Sascha Hauer. It contains
improvements authored by Markus Niebel and Uwe Kleine-König.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Markus Niebel <Markus.Niebel@tq-group.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'include/linux/mmc/host.h')
| -rw-r--r-- | include/linux/mmc/host.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 7960424d0bc0..4cbf61476999 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -365,6 +365,9 @@ struct mmc_host { unsigned int slotno; /* used for sdio acpi binding */ + int dsr_req; /* DSR value is valid */ + u32 dsr; /* optional driver stage (DSR) value */ + unsigned long private[0] ____cacheline_aligned; }; |