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Subject[PATCH] mmc: mmci: stm32: check when the voltage switch procedure should be done
Date
From: Christophe Kerello <christophe.kerello@foss.st.com>

If the card has not been power cycled, it may still be using 1.8V
signaling. This situation is detected in mmc_sd_init_card function and
should be handled in mmci stm32 variant.
The host->pwr_reg variable is also correctly protected with spin locks.

Fixes: 94b94a93e355 ("mmc: mmci_sdmmc: Implement signal voltage callbacks")

Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
---
drivers/mmc/host/mmci_stm32_sdmmc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index 51db30acf4dc..fdaa11f92fe6 100644
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -479,8 +479,9 @@ static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
u32 status;
int ret = 0;

- if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
- spin_lock_irqsave(&host->lock, flags);
+ spin_lock_irqsave(&host->lock, flags);
+ if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 &&
+ host->pwr_reg & MCI_STM32_VSWITCHEN) {
mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
spin_unlock_irqrestore(&host->lock, flags);

@@ -492,9 +493,11 @@ static int sdmmc_post_sig_volt_switch(struct mmci_host *host,

writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
host->base + MMCICLEAR);
+ spin_lock_irqsave(&host->lock, flags);
mmci_write_pwrreg(host, host->pwr_reg &
~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
}
+ spin_unlock_irqrestore(&host->lock, flags);

return ret;
}
--
2.17.1
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