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SubjectRe: [RFC PATCH 5/8] mtd: rawnand: ams-delta: Request data port GPIO resource
On Thu, 19 Jul 2018 01:57:07 +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, we can already
> obtain exclusive access to the port by requesting an array of its GPIO
> descriptors. For that to work on Amstrad Delta, respective GPIO lookup
> table entries are added to the board init file.
>
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
> ---
> arch/arm/mach-omap1/board-ams-delta.c | 11 ++++++++++-
> drivers/mtd/nand/raw/ams-delta.c | 8 ++++++++

Can we split that in 2 patches: one adding data entries to the lookup
table, and another one patching the driver to request the gpiod array.

> 2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-omap1/board-ams-delta.c b/arch/arm/mach-omap1/board-ams-delta.c
> index eedacdfe9725..16f7bbe47607 100644
> --- a/arch/arm/mach-omap1/board-ams-delta.c
> +++ b/arch/arm/mach-omap1/board-ams-delta.c
> @@ -337,7 +337,8 @@ static struct platform_device ams_delta_nand_device = {
> .resource = ams_delta_nand_resources,
> };
>
> -#define OMAP_GPIO_LABEL "gpio-0-15"
> +#define OMAP_GPIO_LABEL "gpio-0-15"
> +#define OMAP_MPUIO_LABEL "mpuio"
>
> static struct gpiod_lookup_table ams_delta_nand_gpio_table = {
> .table = {
> @@ -349,6 +350,14 @@ static struct gpiod_lookup_table ams_delta_nand_gpio_table = {
> GPIO_LOOKUP(LATCH2_LABEL, LATCH2_PIN_NAND_NWE, "nwe", 0),
> GPIO_LOOKUP(LATCH2_LABEL, LATCH2_PIN_NAND_ALE, "ale", 0),
> GPIO_LOOKUP(LATCH2_LABEL, LATCH2_PIN_NAND_CLE, "cle", 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 0, "data", 0, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 1, "data", 1, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 2, "data", 2, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 3, "data", 3, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 4, "data", 4, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 5, "data", 5, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 6, "data", 6, 0),
> + GPIO_LOOKUP_IDX(OMAP_MPUIO_LABEL, 7, "data", 7, 0),
> { },
> },
> };
> diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
> index d7e4c9dbef67..ad62c0245458 100644
> --- a/drivers/mtd/nand/raw/ams-delta.c
> +++ b/drivers/mtd/nand/raw/ams-delta.c
> @@ -189,6 +189,7 @@ 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)
> @@ -289,6 +290,13 @@ 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 output and set low */
> + data_gpiods = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_OUT_LOW);
> + 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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