[PATCH 2/7] mtd: OneNAND: add enable / disable methods to onenand_chip

[Kyungmin Park]

Hi,

Now I'm used the clock gating for OneNAND instead of regulator.
so I think the mechanism is similar.

On Mon, Dec 13, 2010 at 9:20 PM, Adrian Hunter <adrian.hunter at nokia.com> wrote:
> From 16b760999cb79f9cf71728c9253f1399717be63a Mon Sep 17 00:00:00 2001
> From: Adrian Hunter <adrian.hunter at nokia.com>
> Date: Fri, 19 Feb 2010 15:39:52 +0100
> Subject: [PATCH 2/7] mtd: OneNAND: add enable / disable methods to onenand_chip
>
> Add enable / disable methods called from get_device() / release_device().
> These can be used, for example, to allow the driver to prevent the voltage
> regulator from being put to sleep while OneNAND is in use.
>
> Signed-off-by: Adrian Hunter <adrian.hunter at nokia.com>
> ---
>  drivers/mtd/onenand/onenand_base.c |    4 ++++
>  include/linux/mtd/onenand.h        |    2 ++
>  2 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
> index c38bf9c..bde274f 100644
> --- a/drivers/mtd/onenand/onenand_base.c
> +++ b/drivers/mtd/onenand/onenand_base.c
> @@ -948,6 +948,8 @@ static int onenand_get_device(struct mtd_info *mtd, int new_state)
>                if (this->state == FL_READY) {
>                        this->state = new_state;
>                        spin_unlock(&this->chip_lock);
> +                       if (this->enable)
> +                               this->enable(mtd);
>                        break;
>                }
>                if (new_state == FL_PM_SUSPENDED) {

I put the code the end of function like:

static int onenand_get_device(struct mtd_info *mtd, int new_state)
{
        struct onenand_chip *this = mtd->priv;
        DECLARE_WAITQUEUE(wait, current);

        /*
         * Grab the lock and see if the device is available
         */
        while (1) {
                spin_lock(&this->chip_lock);
                if (this->state == FL_READY) {
                        this->state = new_state;
                        spin_unlock(&this->chip_lock);
                        break;
                }
                if (new_state == FL_PM_SUSPENDED) {
                        spin_unlock(&this->chip_lock);
                        return (this->state == FL_PM_SUSPENDED) ? 0 : -EAGAIN;
                }
                set_current_state(TASK_UNINTERRUPTIBLE);
                add_wait_queue(&this->wq, &wait);
                spin_unlock(&this->chip_lock);
                schedule();
                remove_wait_queue(&this->wq, &wait);
        }

        if (this->clk)
                clk_enable(this->clk);

        return 0;
}


> @@ -974,6 +976,8 @@ static void onenand_release_device(struct mtd_info *mtd)
>  {
>        struct onenand_chip *this = mtd->priv;
>
> +       if (this->state != FL_PM_SUSPENDED && this->disable)
> +               this->disable(mtd);
Need to check the SUSPENDED at here? when enter the suspend get_device
is called.
release device is called when resume. so no need to check
FL_PM_SUSPENDED in my case.

>        /* Release the chip */
>        spin_lock(&this->chip_lock);
>        this->state = FL_READY;

and put the same as like:

static void onenand_release_device(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;

        /* Release the chip */
        spin_lock(&this->chip_lock);
        this->state = FL_READY;
        wake_up(&this->wq);
        spin_unlock(&this->chip_lock);

        if (this->clk)
                clk_disable(this->clk);
}

Thank you,
Kyungmin Park

> diff --git a/include/linux/mtd/onenand.h b/include/linux/mtd/onenand.h
> index 6da3fe3..ae418e4 100644
> --- a/include/linux/mtd/onenand.h
> +++ b/include/linux/mtd/onenand.h
> @@ -118,6 +118,8 @@ struct onenand_chip {
>        int (*chip_probe)(struct mtd_info *mtd);
>        int (*block_markbad)(struct mtd_info *mtd, loff_t ofs);
>        int (*scan_bbt)(struct mtd_info *mtd);
> +       int (*enable)(struct mtd_info *mtd);
> +       int (*disable)(struct mtd_info *mtd);
>
>        struct completion       complete;
>        int                     irq;
> --
> 1.7.0.4
>
>
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