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SubjectRe: [RFC PATCH v2 04/12] mtd: rawnand: ams-delta: request data port GPIO resource
On Tue,  7 Aug 2018 00:29:10 +0200
Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:

> Data port used by the driver is actually an OMAP MPUIO device, already
> under control of gpio-omap driver. For that reason we used to not
> request the memory region of the port as that would fail because the
> region is already busy. Despite that, we are still accessing the port
> by just ioremapping it and performing read/write operations. Moreover,
> we are doing that without any proteciton from other users legally
> manipulating the port pins over GPIO API.
>
> The plan is to convert the driver to access the port over functions
> exposed by the gpio-omap driver. Before that happens, already prevent
> from other users accessing the port pins by requesting an array of its
> GPIO descriptors.
>
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>

Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>

> ---
> drivers/mtd/nand/raw/ams-delta.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
> index 48233d638d2a..09d6901fc94d 100644
> --- a/drivers/mtd/nand/raw/ams-delta.c
> +++ b/drivers/mtd/nand/raw/ams-delta.c
> @@ -161,6 +161,7 @@ static int ams_delta_init(struct platform_device *pdev)
> struct mtd_info *mtd;
> struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> void __iomem *io_base;
> + struct gpio_descs *data_gpiods;
> int err = 0;
>
> if (!res)
> @@ -261,6 +262,13 @@ static int ams_delta_init(struct platform_device *pdev)
> dev_err(&pdev->dev, "CLE GPIO request failed (%d)\n", err);
> goto out_mtd;
> }
> + /* Request array of data pins, initialize them as input */
> + data_gpiods = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_IN);
> + if (IS_ERR(data_gpiods)) {
> + err = PTR_ERR(data_gpiods);
> + dev_err(&pdev->dev, "data GPIO request failed: %d\n", err);
> + goto out_mtd;
> + }
>
> /* Scan to find existence of the device */
> err = nand_scan(mtd, 1);

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