linux-kernel - [RFC PATCH 4/7] mmc: sdhci: Add quirk to indicate broken POWER

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Date:   Mon, 7 Aug 2017 21:31:39 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        Tony Lindgren <tony@...mide.com>,
        Rob Herring <robh+dt@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>
CC:     <kishon@...com>, <nsekhar@...com>, <linux-omap@...r.kernel.org>,
        <linux-mmc@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH 4/7] mmc: sdhci: Add quirk to indicate broken POWER_CONTROL

TI's implementation of sdhci controller used in DRA7 SoC's uses
POWER_CONTROL register for configuring IO voltage and not
for core voltage (vdd) which is it's intended use. Add a quirk
to indicate broken POWER_CONTROL register.

Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
---
 drivers/mmc/host/sdhci.c | 6 ++++++
 drivers/mmc/host/sdhci.h | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d5050ec42481..a7465a56e6b5 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1419,6 +1419,9 @@ static void sdhci_set_power_reg(struct sdhci_host *host, unsigned char mode,
 
 	mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
 
+	if (host->quirks2 & SDHCI_QUIRK2_BROKEN_POWER_CONTROL)
+		return;
+
 	if (mode != MMC_POWER_OFF)
 		sdhci_writeb(host, SDHCI_POWER_ON, SDHCI_POWER_CONTROL);
 	else
@@ -1430,6 +1433,9 @@ void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
 {
 	u8 pwr = 0;
 
+	if (host->quirks2 & SDHCI_QUIRK2_BROKEN_POWER_CONTROL)
+		return;
+
 	if (mode != MMC_POWER_OFF) {
 		switch (1 << vdd) {
 		case MMC_VDD_165_195:
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 39c7a2723906..ba94cca7c892 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -439,6 +439,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK2_NO_CRC_STRIPPING			(1<<16)
 /* Controller has bad caps bits, but really supports DMA */
 #define SDHCI_QUIRK2_FORCE_ADMA				(1<<17)
+/* Controller uses POWER_CONTROL for managing IO voltage and not core voltage */
+#define SDHCI_QUIRK2_BROKEN_POWER_CONTROL		(1<<18)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */
-- 
2.11.0