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authorKyle Roeschley <kyle.roeschley@ni.com>2018-04-13 16:54:57 -0500
committerUlf Hansson <ulf.hansson@linaro.org>2018-05-02 15:08:44 +0200
commit247cfe53557524a94dd1001d19e5aa50bd5aca81 (patch)
tree73c891362517c86cc25e5fc85b1ee48188a1a6aa /drivers/mmc/core/sd.c
parent1d6efe08c80d84b1f39845707288ffd4df239c3b (diff)
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mmc: core: Add capability to avoid 3.3V signaling
Some SD host controllers cannot handle extended use of 3.3V signaling. To accommodate these controllers, add a capability that requires us to negotiate the voltage down from 3.3V during card initialization. Signed-off-by: Kyle Roeschley <kyle.roeschley@ni.com> Signed-off-by: Jennifer Dahm <jennifer.dahm@ni.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc/core/sd.c')
-rw-r--r--drivers/mmc/core/sd.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index baf3d5da4ccb..7f87a5354f9f 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1058,6 +1058,14 @@ retry:
mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
}
}
+
+ if (host->caps2 & MMC_CAP2_AVOID_3_3V &&
+ host->ios.signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
+ pr_err("%s: Host failed to negotiate down from 3.3V\n",
+ mmc_hostname(host));
+ err = -EINVAL;
+ goto free_card;
+ }
done:
host->card = card;
return 0;