Re: [PATCH v5 17/26] mtd: nand: omap2: Implement NAND ready using gpiolib

From: Boris Brezillon
Date: Mon Mar 07 2016 - 04:22:31 EST


On Fri, 19 Feb 2016 23:15:39 +0200
Roger Quadros <rogerq@xxxxxx> wrote:

> 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@xxxxxx>

Acked-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>

> ---
> .../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



--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com