mmc: sdhci: Do not invert write-protect twice

mmc_of_parse() reads device property "wp-inverted" and sets
MMC_CAP2_RO_ACTIVE_HIGH if it is true. MMC_CAP2_RO_ACTIVE_HIGH is used
to invert a write-protect (AKA read-only) GPIO value.

sdhci_get_property() also reads "wp-inverted" and sets
SDHCI_QUIRK_INVERTED_WRITE_PROTECT which is used to invert the
write-protect value as well but also acts upon a value read out from the
SDHCI_PRESENT_STATE register.

Many drivers call both mmc_of_parse() and sdhci_get_property(),
so that both MMC_CAP2_RO_ACTIVE_HIGH and
SDHCI_QUIRK_INVERTED_WRITE_PROTECT will be set if the controller has
device property "wp-inverted".

Amend the logic in sdhci_check_ro() to allow for that possibility,
so that the write-protect value is not inverted twice.

Also do not invert the value if it is a negative error value. Note that
callers treat an error the same as not-write-protected, so the result is
functionally the same in that case.

Also do not invert the value if sdhci host operation ->get_ro() is used.
None of the users of that callback set SDHCI_QUIRK_INVERTED_WRITE_PROTECT
directly or indirectly, but two do call mmc_gpio_get_ro(), so leave it to
them to deal with that if they ever set SDHCI_QUIRK_INVERTED_WRITE_PROTECT
in the future.

Fixes: 6d5cd068ee59 ("mmc: sdhci: use WP GPIO in sdhci_check_ro()")
Signed-off-by: Adrian Hunter <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/sdhci.c

···
 
 static int sdhci_check_ro(struct sdhci_host *host)
 {
+	bool allow_invert = false;
 	unsigned long flags;
 	int is_readonly;
 
 	spin_lock_irqsave(&host->lock, flags);
 
-	if (host->flags & SDHCI_DEVICE_DEAD)
+	if (host->flags & SDHCI_DEVICE_DEAD) {
 		is_readonly = 0;
-	else if (host->ops->get_ro)
+	} else if (host->ops->get_ro) {
 		is_readonly = host->ops->get_ro(host);
-	else if (mmc_can_gpio_ro(host->mmc))
+	} else if (mmc_can_gpio_ro(host->mmc)) {
 		is_readonly = mmc_gpio_get_ro(host->mmc);
-	else
+		/* Do not invert twice */
+		allow_invert = !(host->mmc->caps2 & MMC_CAP2_RO_ACTIVE_HIGH);
+	} else {
 		is_readonly = !(sdhci_readl(host, SDHCI_PRESENT_STATE)
 				& SDHCI_WRITE_PROTECT);
+		allow_invert = true;
+	}
 
 	spin_unlock_irqrestore(&host->lock, flags);
 
-	/* This quirk needs to be replaced by a callback-function later */
-	return host->quirks & SDHCI_QUIRK_INVERTED_WRITE_PROTECT ?
-		!is_readonly : is_readonly;
+	if (is_readonly >= 0 &&
+	    allow_invert &&
+	    (host->quirks & SDHCI_QUIRK_INVERTED_WRITE_PROTECT))
+		is_readonly = !is_readonly;
+
+	return is_readonly;
 }
 
 #define SAMPLE_COUNT	5