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mtd: rawnand: ams-delta: Write protect device during probe

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Initialise NWP GPIO pin as asserted to protect the device from hazard
during setup of other GPIO pins.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200212003929.6682-2-jmkrzyszt@gmail.com
This commit is contained in:
Janusz Krzysztofik 2020-02-12 01:39:16 +01:00 committed by Miquel Raynal
parent c4b7dd35d3
commit 91a1abfb75
1 changed files with 16 additions and 2 deletions
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18
drivers/mtd/nand/raw/ams-delta.c
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@ -251,8 +251,8 @@ static int ams_delta_init(struct platform_device *pdev)
platform_set_drvdata(pdev, priv);
/* Set chip enabled, but */
priv->gpiod_nwp = devm_gpiod_get(&pdev->dev, "nwp", GPIOD_OUT_HIGH);
/* Set chip enabled but write protected */
priv->gpiod_nwp = devm_gpiod_get(&pdev->dev, "nwp", GPIOD_OUT_LOW);
if (IS_ERR(priv->gpiod_nwp)) {
err = PTR_ERR(priv->gpiod_nwp);
dev_err(&pdev->dev, "NWP GPIO request failed (%d)\n", err);
@ -309,6 +309,17 @@ static int ams_delta_init(struct platform_device *pdev)
nand_controller_init(&priv->base);
this->controller = &priv->base;
/*
* FIXME: We should release write protection only after nand_scan() to
* be on the safe side but we can't do that until we have a generic way
* to assert/deassert WP from the core. Even if the core shouldn't
* write things in the nand_scan() path, it should have control on this
* pin just in case we ever need to disable write protection during
* chip detection/initialization.
*/
/* Release write protection */
gpiod_set_value(priv->gpiod_nwp, 1);
/* Scan to find existence of the device */
err = nand_scan(this, 1);
if (err)
@ -336,6 +347,9 @@ static int ams_delta_cleanup(struct platform_device *pdev)
struct ams_delta_nand *priv = platform_get_drvdata(pdev);
struct mtd_info *mtd = nand_to_mtd(&priv->nand_chip);
/* Apply write protection */
gpiod_set_value(priv->gpiod_nwp, 0);
/* Unregister device */
nand_release(mtd_to_nand(mtd));