Re: [PATCH 5/6 v2] mtd: rawnand: ams-delta: use GPIO lookup table

Boris Brezillon
2018-05-30T09:05:22Z

Hi Janusz,

On Sat, 26 May 2018 00:20:45 +0200
Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:

> Now as the Amstrad Delta board provides GPIO lookup tables, switch from
> GPIO numbers to GPIO descriptors and use the table to locate required
> GPIO pins.
>
> Declare static variables for storing GPIO descriptors and replace
> gpio_ functions with their gpiod_ equivalents. Return -EPROBE_DEFER
> if the GPIO pins are not yet available so device initialization is
> postponed instead of aborted.
>
> Pin naming used by the driver should be followed while respective GPIO
> lookup table is initialized by a board init code.
>
> Created and tested against linux-4.17-rc3, on top of patch 1/6 "ARM:
> OMAP1: ams-delta: add GPIO lookup tables" (already applied to
> omap-for-v4.18/soc tree).
>
> Changes since v1:
> - fix handling of devm_gpiod_get_optional() return values - thanks to
> Andy Shevchenko.

Can you put the changelog after the "---" separator so that it does not
appear in the final commit message?

>
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
> ---
> drivers/mtd/nand/raw/ams-delta.c | 120 +++++++++++++++++++++------------------
> 1 file changed, 64 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
> index 37a3cc21c7bc..524ceaf12de0 100644
> --- a/drivers/mtd/nand/raw/ams-delta.c
> +++ b/drivers/mtd/nand/raw/ams-delta.c
> @@ -20,23 +20,28 @@
> #include <linux/slab.h>
> #include <linux/module.h>
> #include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/mtd/mtd.h>
> #include <linux/mtd/rawnand.h>
> #include <linux/mtd/partitions.h>
> -#include <linux/gpio.h>
> #include <linux/platform_data/gpio-omap.h>
>
> #include <asm/io.h>
> #include <asm/sizes.h>
>
> -#include <mach/board-ams-delta.h>
> -
> #include <mach/hardware.h>
>
> /*
> * MTD structure for E3 (Delta)
> */
> static struct mtd_info *ams_delta_mtd = NULL;
> +static struct gpio_desc *gpiod_rdy;
> +static struct gpio_desc *gpiod_nce;
> +static struct gpio_desc *gpiod_nre;
> +static struct gpio_desc *gpiod_nwp;
> +static struct gpio_desc *gpiod_nwe;
> +static struct gpio_desc *gpiod_ale;
> +static struct gpio_desc *gpiod_cle;
>
> /*
> * Define partitions for flash devices
> @@ -70,9 +75,9 @@ static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
>
> writew(0, io_base + OMAP_MPUIO_IO_CNTL);
> writew(byte, this->IO_ADDR_W);
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NWE, 0);
> + gpiod_set_value(gpiod_nwe, 0);
> ndelay(40);
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NWE, 1);
> + gpiod_set_value(gpiod_nwe, 1);
> }
>
> static u_char ams_delta_read_byte(struct mtd_info *mtd)
> @@ -81,11 +86,11 @@ static u_char ams_delta_read_byte(struct mtd_info *mtd)
> struct nand_chip *this = mtd_to_nand(mtd);
> void __iomem *io_base = (void __iomem *)nand_get_controller_data(this);
>
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NRE, 0);
> + gpiod_set_value(gpiod_nre, 0);
> ndelay(40);
> writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
> res = readw(this->IO_ADDR_R);
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NRE, 1);
> + gpiod_set_value(gpiod_nre, 1);
>
> return res;
> }
> @@ -120,12 +125,9 @@ static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
> {
>
> if (ctrl & NAND_CTRL_CHANGE) {
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_NCE,
> - (ctrl & NAND_NCE) == 0);
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_CLE,
> - (ctrl & NAND_CLE) != 0);
> - gpio_set_value(AMS_DELTA_GPIO_PIN_NAND_ALE,
> - (ctrl & NAND_ALE) != 0);
> + gpiod_set_value(gpiod_nce, !(ctrl & NAND_NCE));
> + gpiod_set_value(gpiod_cle, !!(ctrl & NAND_CLE));
> + gpiod_set_value(gpiod_ale, !!(ctrl & NAND_ALE));
> }
>
> if (cmd != NAND_CMD_NONE)
> @@ -134,41 +136,9 @@ static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
>
> static int ams_delta_nand_ready(struct mtd_info *mtd)
> {
> - return gpio_get_value(AMS_DELTA_GPIO_PIN_NAND_RB);
> + return gpiod_get_value(gpiod_rdy);
> }
>
> -static const struct gpio _mandatory_gpio[] = {
> - {
> - .gpio = AMS_DELTA_GPIO_PIN_NAND_NCE,
> - .flags = GPIOF_OUT_INIT_HIGH,
> - .label = "nand_nce",
> - },
> - {
> - .gpio = AMS_DELTA_GPIO_PIN_NAND_NRE,
> - .flags = GPIOF_OUT_INIT_HIGH,
> - .label = "nand_nre",
> - },
> - {
> - .gpio = AMS_DELTA_GPIO_PIN_NAND_NWP,
> - .flags = GPIOF_OUT_INIT_HIGH,
> - .label = "nand_nwp",
> - },
> - {
> - .gpio = AMS_DELTA_GPIO_PIN_NAND_NWE,
> - .flags = GPIOF_OUT_INIT_HIGH,
> - .label = "nand_nwe",
> - },
> - {
> - .gpio = AMS_DELTA_GPIO_PIN_NAND_ALE,
> - .flags = GPIOF_OUT_INIT_LOW,
> - .label = "nand_ale",
> - },
> - {
> - .gpio = AMS_DELTA_GPIO_PIN_NAND_CLE,
> - .flags = GPIOF_OUT_INIT_LOW,
> - .label = "nand_cle",
> - },
> -};
>
> /*
> * Main initialization routine
> @@ -216,12 +186,17 @@ static int ams_delta_init(struct platform_device *pdev)
> this->write_buf = ams_delta_write_buf;
> this->read_buf = ams_delta_read_buf;
> this->cmd_ctrl = ams_delta_hwcontrol;
> - if (gpio_request(AMS_DELTA_GPIO_PIN_NAND_RB, "nand_rdy") == 0) {
> - this->dev_ready = ams_delta_nand_ready;
> - } else {
> - this->dev_ready = NULL;
> - pr_notice("Couldn't request gpio for Delta NAND ready.\n");
> +
> + gpiod_rdy = devm_gpiod_get_optional(&pdev->dev, "rdy", GPIOD_IN);
> + if (IS_ERR(gpiod_rdy)) {
> + err = PTR_ERR(gpiod_rdy);
> + dev_warn(&pdev->dev, "RDY GPIO request failed (%d)\n", err);
> + goto err_gpiod;
> }
> +
> + if (gpiod_rdy)
> + this->dev_ready = ams_delta_nand_ready;
> +
> /* 25 us command delay time */
> this->chip_delay = 30;
> this->ecc.mode = NAND_ECC_SOFT;
> @@ -230,7 +205,44 @@ static int ams_delta_init(struct platform_device *pdev)
> platform_set_drvdata(pdev, io_base);
>
> /* Set chip enabled, but */
> - err = gpio_request_array(_mandatory_gpio, ARRAY_SIZE(_mandatory_gpio));
> + gpiod_nwp = devm_gpiod_get(&pdev->dev, "nwp", GPIOD_OUT_HIGH);
> + if (IS_ERR(gpiod_nwp)) {
> + err = PTR_ERR(gpiod_nwp);
> + dev_err(&pdev->dev, "NWP GPIO request failed (%d)\n", err);
> + goto err_gpiod;
> + }
> + gpiod_nce = devm_gpiod_get(&pdev->dev, "nce", GPIOD_OUT_HIGH);
> + if (IS_ERR(gpiod_nce)) {
> + err = PTR_ERR(gpiod_nce);
> + dev_err(&pdev->dev, "NCE GPIO request failed (%d)\n", err);
> + goto err_gpiod;
> + }
> + gpiod_nre = devm_gpiod_get(&pdev->dev, "nre", GPIOD_OUT_HIGH);
> + if (IS_ERR(gpiod_nre)) {
> + err = PTR_ERR(gpiod_nre);
> + dev_err(&pdev->dev, "NRE GPIO request failed (%d)\n", err);
> + goto err_gpiod;
> + }
> + gpiod_nwe = devm_gpiod_get(&pdev->dev, "nwe", GPIOD_OUT_HIGH);
> + if (IS_ERR(gpiod_nwe)) {
> + err = PTR_ERR(gpiod_nwe);
> + dev_err(&pdev->dev, "NWE GPIO request failed (%d)\n", err);
> + goto err_gpiod;
> + }
> + gpiod_ale = devm_gpiod_get(&pdev->dev, "ale", GPIOD_OUT_LOW);
> + if (IS_ERR(gpiod_ale)) {
> + err = PTR_ERR(gpiod_ale);
> + dev_err(&pdev->dev, "ALE GPIO request failed (%d)\n", err);
> + goto err_gpiod;
> + }
> + gpiod_cle = devm_gpiod_get(&pdev->dev, "cle", GPIOD_OUT_LOW);
> + if (IS_ERR(gpiod_cle)) {
> + err = PTR_ERR(gpiod_cle);
> + dev_err(&pdev->dev, "CLE GPIO request failed (%d)\n", err);
> + }
> +err_gpiod:
> + if (err == -ENODEV || err == -ENOENT)
> + err = -EPROBE_DEFER;

Hm, isn't it better to make gpiod_find() return ERR_PTR(-EPROBE_DEFER)
here [1]? At least, ENOENT should not be turned into EPROBE_DEFER,
because it's returned when there's no entry matching the requested gpio
in the lookup table, and deferring the probe won't solve this problem.

Regards,

Boris

[1]https://elixir.bootlin.com/linux/v4.17-rc7/source/drivers/gpio/gpiolib.c#L3525