From 247cfe53557524a94dd1001d19e5aa50bd5aca81 Mon Sep 17 00:00:00 2001 From: Kyle Roeschley Date: Fri, 13 Apr 2018 16:54:57 -0500 Subject: 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 Signed-off-by: Jennifer Dahm Signed-off-by: Ulf Hansson --- drivers/mmc/core/sd.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/mmc/core/sd.c') 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; -- cgit v1.2.3