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mmc: dt: Allow to specify that no write protect signal is present

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Allow to specify in the device-tree that no physical write-protect signal
is connected to a particular instance of a MMC controller. Setting the
property will cause the core will assume that the SD card is always
read-write.

The name for the new property is 'disable-wp' and was chosen based on the
property with the same function from the Synopsys designware mobile storage
host controller DT bindings specification.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Lars-Peter Clausen 2015-05-06 20:31:20 +02:00 committed by Ulf Hansson
parent 9f6e0bff2a
commit 19f4424677
2 changed files with 8 additions and 0 deletions
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5
Documentation/devicetree/bindings/mmc/mmc.txt
View File

@ -21,6 +21,11 @@ Optional properties:
below for the case, when a GPIO is used for the CD line below for the case, when a GPIO is used for the CD line
- wp-inverted: when present, polarity on the WP line is inverted. See the note - wp-inverted: when present, polarity on the WP line is inverted. See the note
below for the case, when a GPIO is used for the WP line below for the case, when a GPIO is used for the WP line
- disable-wp: When set no physical WP line is present. This property should
only be specified when the controller has a dedicated write-protect
detection logic. If a GPIO is always used for the write-protect detection
logic it is sufficient to not specify wp-gpios property in the absence of a WP
line.
- max-frequency: maximum operating clock frequency - max-frequency: maximum operating clock frequency
- no-1-8-v: when present, denotes that 1.8v card voltage is not supported on - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
this system, even if the controller claims it is. this system, even if the controller claims it is.

3
drivers/mmc/core/host.c
View File

@ -484,6 +484,9 @@ int mmc_of_parse(struct mmc_host *host)
else if (ret != -ENOENT) else if (ret != -ENOENT)
return ret; return ret;
if (of_property_read_bool(np, "disable-wp"))
host->caps2 |= MMC_CAP2_NO_WRITE_PROTECT;
/* See the comment on CD inversion above */ /* See the comment on CD inversion above */
if (ro_cap_invert ^ ro_gpio_invert) if (ro_cap_invert ^ ro_gpio_invert)
host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH; host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH;