linux-kernel - [PATCH v2] mmc: mmci: manage MMC_PM_KEEP

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Message-ID: <20220314125554.190574-1-yann.gautier@foss.st.com>
Date:   Mon, 14 Mar 2022 13:55:54 +0100
From:   Yann Gautier <yann.gautier@...s.st.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-mmc@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        Christophe Kerello <christophe.kerello@...s.st.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Ludovic Barre <ludovic.barre@...s.st.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Russell King <linux@...linux.org.uk>,
        Marek Vasut <marex@...x.de>, <kernel@...electronics.com>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Grzegorz Szymaszek <gszymaszek@...rt.pl>,
        Yann Gautier <yann.gautier@...s.st.com>
Subject: [PATCH v2] mmc: mmci: manage MMC_PM_KEEP_POWER per variant config

Add a disable_keep_power field in variant_data struct. The
MMC_PM_KEEP_POWER flag will be enabled if disable_keep_power is not set.
It is only set to true for stm32_sdmmc variants.

The issue was seen on STM32MP157C-DK2 board, which embeds a wifi chip.
It doesn't correctly support low power on this board. The Wifi chip
awaits an always-on regulator, but it was connected to v3v3 which is off
in low-power sequence. MMC_PM_KEEP_POWER should then be disabled.

The flag can still be enabled through DT property:
keep-power-in-suspend.

Signed-off-by: Yann Gautier <yann.gautier@...s.st.com>
---
Update in v2:
Reword commit message to better explain the issue.

Resend the patch alone. It was previoulsy in a series [1] for which the
other patches will be reworked.

[1] https://lore.kernel.org/lkml/20220304135134.47827-1-yann.gautier@foss.st.com/

 drivers/mmc/host/mmci.c | 5 ++++-
 drivers/mmc/host/mmci.h | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 45b8608c935c..0e2f2f5d6a52 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -274,6 +274,7 @@ static struct variant_data variant_stm32_sdmmc = {
 	.busy_detect		= true,
 	.busy_detect_flag	= MCI_STM32_BUSYD0,
 	.busy_detect_mask	= MCI_STM32_BUSYD0ENDMASK,
+	.disable_keep_power	= true,
 	.init			= sdmmc_variant_init,
 };
 
@@ -301,6 +302,7 @@ static struct variant_data variant_stm32_sdmmcv2 = {
 	.busy_detect		= true,
 	.busy_detect_flag	= MCI_STM32_BUSYD0,
 	.busy_detect_mask	= MCI_STM32_BUSYD0ENDMASK,
+	.disable_keep_power	= true,
 	.init			= sdmmc_variant_init,
 };
 
@@ -2172,7 +2174,8 @@ static int mmci_probe(struct amba_device *dev,
 	host->stop_abort.flags = MMC_RSP_R1B | MMC_CMD_AC;
 
 	/* We support these PM capabilities. */
-	mmc->pm_caps |= MMC_PM_KEEP_POWER;
+	if (!variant->disable_keep_power)
+		mmc->pm_caps |= MMC_PM_KEEP_POWER;
 
 	/*
 	 * We can do SGIO
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index e1a9b96a3396..2cad1ef9766a 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -361,6 +361,7 @@ struct variant_data {
 	u32			opendrain;
 	u8			dma_lli:1;
 	u32			stm32_idmabsize_mask;
+	u8			disable_keep_power:1;
 	void (*init)(struct mmci_host *host);
 };
 
-- 
2.25.1