[PATCH 5/5] ARM: SAMSUNG: Add to enable/disable clock on S3C PL330

[Kyungmin Park]

On Thu, Oct 21, 2010 at 9:58 AM, Kukjin Kim <kgene.kim at samsung.com> wrote:
> From: Seungwhan Youn <sw.youn at samsung.com>
>
> This patch adds to enable/disable DMA operation clock on S3C-PL330
> DMA controller driver.

The title and description seems to clock gating but actual code is
just enable at probe and disable at remove.

Can you make it REAL clock gating, enable clock only when using?

Thank you,
Kyungmin Park
>
> Signed-off-by: Seungwhan Youn <sw.youn at samsung.com>
> Acked-by: Jassi Brar <jassi.brar at samsung.com>
> Signed-off-by: Kukjin Kim <kgene.kim at samsung.com>
> ---
>  arch/arm/plat-samsung/s3c-pl330.c |   34 +++++++++++++++++++++++++++-------
>  1 files changed, 27 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm/plat-samsung/s3c-pl330.c b/arch/arm/plat-samsung/s3c-pl330.c
> index a91305a..b4ff8d7 100644
> --- a/arch/arm/plat-samsung/s3c-pl330.c
> +++ b/arch/arm/plat-samsung/s3c-pl330.c
> @@ -15,6 +15,8 @@
>  #include <linux/io.h>
>  #include <linux/slab.h>
>  #include <linux/platform_device.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
>
>  #include <asm/hardware/pl330.h>
>
> @@ -27,6 +29,7 @@
>  * @node: To attach to the global list of DMACs.
>  * @pi: PL330 configuration info for the DMAC.
>  * @kmcache: Pool to quickly allocate xfers for all channels in the dmac.
> + * @clk: Pointer of DMAC operation clock.
>  */
>  struct s3c_pl330_dmac {
>        unsigned                busy_chan;
> @@ -34,6 +37,7 @@ struct s3c_pl330_dmac {
>        struct list_head        node;
>        struct pl330_info       *pi;
>        struct kmem_cache       *kmcache;
> +       struct clk              *clk;
>  };
>
>  /**
> @@ -1072,16 +1076,25 @@ static int pl330_probe(struct platform_device *pdev)
>        if (ret)
>                goto probe_err4;
>
> -       ret = pl330_add(pl330_info);
> -       if (ret)
> -               goto probe_err5;
> -
>        /* Allocate a new DMAC */
>        s3c_pl330_dmac = kmalloc(sizeof(*s3c_pl330_dmac), GFP_KERNEL);
>        if (!s3c_pl330_dmac) {
>                ret = -ENOMEM;
> +               goto probe_err5;
> +       }
> +
> +       /* Get operation clock and enable it */
> +       s3c_pl330_dmac->clk = clk_get(&pdev->dev, "pdma");
> +       if (IS_ERR(s3c_pl330_dmac->clk)) {
> +               dev_err(&pdev->dev, "Cannot get operation clock.\n");
> +               ret = -EINVAL;
>                goto probe_err6;
>        }
> +       clk_enable(s3c_pl330_dmac->clk);
> +
> +       ret = pl330_add(pl330_info);
> +       if (ret)
> +               goto probe_err7;
>
>        /* Hook the info */
>        s3c_pl330_dmac->pi = pl330_info;
> @@ -1094,7 +1107,7 @@ static int pl330_probe(struct platform_device *pdev)
>
>        if (!s3c_pl330_dmac->kmcache) {
>                ret = -ENOMEM;
> -               goto probe_err7;
> +               goto probe_err8;
>        }
>
>        /* Get the list of peripherals */
> @@ -1120,10 +1133,13 @@ static int pl330_probe(struct platform_device *pdev)
>
>        return 0;
>
> +probe_err8:
> +       pl330_del(pl330_info);
>  probe_err7:
> -       kfree(s3c_pl330_dmac);
> +       clk_disable(s3c_pl330_dmac->clk);
> +       clk_put(s3c_pl330_dmac->clk);
>  probe_err6:
> -       pl330_del(pl330_info);
> +       kfree(s3c_pl330_dmac);
>  probe_err5:
>        free_irq(irq, pl330_info);
>  probe_err4:
> @@ -1188,6 +1204,10 @@ static int pl330_remove(struct platform_device *pdev)
>                }
>        }
>
> +       /* Disable operation clock */
> +       clk_disable(dmac->clk);
> +       clk_put(dmac->clk);
> +
>        /* Remove the DMAC */
>        list_del(&dmac->node);
>        kfree(dmac);
> --
> 1.6.2.5
>
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