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    Subject[PATCH v5 17/26] mtd: nand: omap2: Implement NAND ready using gpiolib
    Date
    The GPMC WAIT pin status are now available over gpiolib.
    Update the omap_dev_ready() function to use gpio instead of
    directly accessing GPMC register space.

    Signed-off-by: Roger Quadros <rogerq@ti.com>
    ---
    .../devicetree/bindings/mtd/gpmc-nand.txt | 2 ++
    drivers/mtd/nand/omap2.c | 29 ++++++++++++++--------
    include/linux/platform_data/mtd-nand-omap2.h | 2 +-
    3 files changed, 21 insertions(+), 12 deletions(-)

    diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
    index 810b87b..256bb86 100644
    --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
    +++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
    @@ -48,6 +48,7 @@ Optional properties:
    locating ECC errors for BCHx algorithms. SoC devices which have
    ELM hardware engines should specify this device node in .dtsi
    Using ELM for ECC error correction frees some CPU cycles.
    + - rb-gpios: GPIO specifier for the ready/busy# pin.

    For inline partition table parsing (optional):

    @@ -78,6 +79,7 @@ Example for an AM33xx board:
    ti,nand-xfer-type = "polled";
    interrupt-parent = <&gpmc>;
    interrupts = <0>, <1>;
    + rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */

    gpmc,sync-clk-ps = <0>;
    gpmc,cs-on-ns = <0>;
    diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
    index 0a637c4..e7939f1 100644
    --- a/drivers/mtd/nand/omap2.c
    +++ b/drivers/mtd/nand/omap2.c
    @@ -12,6 +12,7 @@
    #include <linux/dmaengine.h>
    #include <linux/dma-mapping.h>
    #include <linux/delay.h>
    +#include <linux/gpio/consumer.h>
    #include <linux/module.h>
    #include <linux/interrupt.h>
    #include <linux/jiffies.h>
    @@ -183,6 +184,8 @@ struct omap_nand_info {
    struct nand_ecclayout oobinfo;
    /* fields specific for BCHx_HW ECC scheme */
    struct device *elm_dev;
    + /* NAND ready gpio */
    + struct gpio_desc *ready_gpiod;
    };

    static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
    @@ -1024,21 +1027,16 @@ static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
    }

    /**
    - * omap_dev_ready - calls the platform specific dev_ready function
    + * omap_dev_ready - checks the NAND Ready GPIO line
    * @mtd: MTD device structure
    + *
    + * Returns true if ready and false if busy.
    */
    static int omap_dev_ready(struct mtd_info *mtd)
    {
    - unsigned int val = 0;
    struct omap_nand_info *info = mtd_to_omap(mtd);

    - val = readl(info->reg.gpmc_status);
    -
    - if ((val & 0x100) == 0x100) {
    - return 1;
    - } else {
    - return 0;
    - }
    + return gpiod_get_value(info->ready_gpiod);
    }

    /**
    @@ -1754,7 +1752,9 @@ static int omap_nand_probe(struct platform_device *pdev)
    info->gpmc_cs = pdata->cs;
    info->reg = pdata->reg;
    info->ecc_opt = pdata->ecc_opt;
    - info->dev_ready = pdata->dev_ready;
    + if (pdata->dev_ready)
    + dev_info(&pdev->dev, "pdata->dev_ready is deprecated\n");
    +
    info->xfer_type = pdata->xfer_type;
    info->devsize = pdata->devsize;
    info->elm_of_node = pdata->elm_of_node;
    @@ -1786,6 +1786,13 @@ static int omap_nand_probe(struct platform_device *pdev)
    nand_chip->IO_ADDR_W = nand_chip->IO_ADDR_R;
    nand_chip->cmd_ctrl = omap_hwcontrol;

    + info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
    + GPIOD_IN);
    + if (IS_ERR(info->ready_gpiod)) {
    + dev_err(dev, "failed to get ready gpio\n");
    + return PTR_ERR(info->ready_gpiod);
    + }
    +
    /*
    * If RDY/BSY line is connected to OMAP then use the omap ready
    * function and the generic nand_wait function which reads the status
    @@ -1793,7 +1800,7 @@ static int omap_nand_probe(struct platform_device *pdev)
    * chip delay which is slightly more than tR (AC Timing) of the NAND
    * device and read status register until you get a failure or success
    */
    - if (info->dev_ready) {
    + if (info->ready_gpiod) {
    nand_chip->dev_ready = omap_dev_ready;
    nand_chip->chip_delay = 0;
    } else {
    diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
    index 7f6de53..17d57a1 100644
    --- a/include/linux/platform_data/mtd-nand-omap2.h
    +++ b/include/linux/platform_data/mtd-nand-omap2.h
    @@ -71,7 +71,6 @@ struct omap_nand_platform_data {
    int cs;
    struct mtd_partition *parts;
    int nr_parts;
    - bool dev_ready;
    bool flash_bbt;
    enum nand_io xfer_type;
    int devsize;
    @@ -82,5 +81,6 @@ struct omap_nand_platform_data {
    /* deprecated */
    struct gpmc_nand_regs reg;
    struct device_node *of_node;
    + bool dev_ready;
    };
    #endif
    --
    2.1.4
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