linux-kernel - [PATCH v2 4/4] mtd: core: Fix a conflict between MTD and NVMEM on wp-gpios property

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Message-ID: <20220131095755.8981-5-christophe.kerello@foss.st.com>
Date:   Mon, 31 Jan 2022 10:57:55 +0100
From:   Christophe Kerello <christophe.kerello@...s.st.com>
To:     <miquel.raynal@...tlin.com>, <richard@....at>, <vigneshr@...com>,
        <robh+dt@...nel.org>, <srinivas.kandagatla@...aro.org>
CC:     <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <devicetree@...r.kernel.org>, <chenshumin86@...a.com>,
        Christophe Kerello <christophe.kerello@...s.st.com>
Subject: [PATCH v2 4/4] mtd: core: Fix a conflict between MTD and NVMEM on wp-gpios property

Wp-gpios property can be used on NVMEM nodes and the same property can
be also used on MTD NAND nodes. In case of the wp-gpios property is
defined at NAND level node, the GPIO management is done at NAND driver
level. Write protect is disabled when the driver is probed or resumed
and is enabled when the driver is released or suspended.

When no partitions are defined in the NAND DT node, then the NAND DT node
will be passed to NVMEM framework. If wp-gpios property is defined in
this node, the GPIO resource is taken twice and the NAND controller
driver fails to probe.

A new Boolean flag named skip_wp_gpio has been added in nvmem_config.
In case skip_wp_gpio is set, it means that the GPIO is handled by the
provider. Lets set this flag in MTD layer to avoid the conflict on
wp_gpios property.

Signed-off-by: Christophe Kerello <christophe.kerello@...s.st.com>
---
 drivers/mtd/mtdcore.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 70f492dce158..e6d251594def 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -546,6 +546,7 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
 	config.stride = 1;
 	config.read_only = true;
 	config.root_only = true;
+	config.skip_wp_gpio = true;
 	config.no_of_node = !of_device_is_compatible(node, "nvmem-cells");
 	config.priv = mtd;

@@ -833,6 +834,7 @@ static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd,
 	config.owner = THIS_MODULE;
 	config.type = NVMEM_TYPE_OTP;
 	config.root_only = true;
+	config.skip_wp_gpio = true;
 	config.reg_read = reg_read;
 	config.size = size;
 	config.of_node = np;
-- 
2.25.1