This patch series attempts to make the 1.8V signal voltage switch
required for UHS mode work according to the SD specification.
These patches have been tested with a couple of UHS SD cards, one of
which sometimes requires up to five power cycles before it accepts the
signal voltage switch. The patches have also been tested with various
other SD cards, as well as one SDIO WLAN chip (cw1200) to check
for regressions. The patches have also been tested with
CONFIG_MMC_CLKGATE.
As usual, I'd be very grateful if someone could help me test this patch
with an UHS SDIO card and perhaps also a combo card (which does seem to
be rare these days?)?
This patch series is based on previous RFC/patch:
[RFC/PATCH v2] mmc: core: Fixup signal voltage switch
and more recently on Kevin Liu's patches:
[PATCH v2 1/3] mmc: core: enhance the code for signal voltage setting
[PATCH v2 2/3] mmc: core: cycle power the card in voltage switch rather than
mmc_sd_get_cid
Changelog:
v1 -> v2
- Move mmc_power_cycle to the mmc_set_signal_voltage function
- Check card_busy before switching voltages
- Return -EPERM if signal voltage switch with cmd11 is
requested, but no start_signal_voltage_switch is defined.
- If we're switching back to 3.3 V, just do the switch without
checking card_busy etc
v2 -> This patch series
- Removed the extra argument to the card_busy host_ops function
- Added mmc_power_cycle
- Some clarifying comments
v1 -> v2
- Removed reset of signal voltage in mmc_sd_get_cid, since
"mmc: core: reset signal voltage on power up"
previous two patches -> v1:
- Keep calls to mmc_host_clk_hold / mmc_host_clk_release
- Add retry-loop / power cycle in sdio.c
- Fall back to 3.3 V if the switch repeatedly fails
- Add an extra argument to the card_busy host_ops function,
which can be used to signal polling use of the function
Johan Rudholm (3):
mmc: core: Add mmc_power_cycle
mmc: core: Add card_busy to host_ops
mmc: core: Fixup signal voltage switch
drivers/mmc/core/core.c | 83 +++++++++++++++++++++++++++++++++++++++++++---
drivers/mmc/core/core.h | 1 +
drivers/mmc/core/sd.c | 21 +++++++++---
drivers/mmc/core/sdio.c | 20 +++++++++--
include/linux/mmc/host.h | 3 ++
5 files changed, 116 insertions(+), 12 deletions(-)
--
1.7.10
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