linux-kernel - [PATCH 4/4] mmc: mmci: initialize pwr|clk|datactrl

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Date:   Wed, 26 Feb 2020 09:40:14 +0100
From:   Ludovic Barre <ludovic.barre@...com>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>
CC:     <srinivas.kandagatla@...aro.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-mmc@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        Ludovic Barre <ludovic.barre@...com>
Subject: [PATCH 4/4] mmc: mmci: initialize pwr|clk|datactrl_reg with their hardware values

In mmci_write_pwr|clk|datactrlreg functions, if the desired value
is equal to corresponding variable (pwr_reg|clk_reg|datactrl_reg),
the value is not written in the register.

At probe pwr|clk|datactrl_reg of mmci_host structure are initialized
to 0 (kzalloc of mmc_alloc_host). But they does not necessarily reflect
hardware value of these registers, if they are used while boot level.
This is problematic, if we want to write 0 in these registers.

This patch initializes pwr|clk|datactrl_reg variables with their
hardware values while probing.

Signed-off-by: Ludovic Barre <ludovic.barre@...com>
---
 drivers/mmc/host/mmci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 647567def612..f378ae18d5dc 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -2085,6 +2085,10 @@ static int mmci_probe(struct amba_device *dev,
 	else if (plat->ocr_mask)
 		dev_warn(mmc_dev(mmc), "Platform OCR mask is ignored\n");
 
+	host->pwr_reg = readl_relaxed(host->base + MMCIPOWER);
+	host->clk_reg = readl_relaxed(host->base + MMCICLOCK);
+	host->datactrl_reg = readl_relaxed(host->base + MMCIDATACTRL);
+
 	/* We support these capabilities. */
 	mmc->caps |= MMC_CAP_CMD23;
 
-- 
2.17.1