[PATCH] ARM: imx: powerdown PLL before changing of its setting

[Fabio Estevam]

Hi Jiada,

On Wed, May 14, 2014 at 6:36 AM, Jiada Wang <jiada_wang at mentor.com> wrote:
> According to i.MX6 user manual,  "Before changing the PLL setting,
> power it down. Power up the PLL after the change"
> But currently PLL setting is being updated without power-down
> it first. This may end up with improper output/gitches which
> prevents furture operation.
>
> Signed-off-by: Jiada Wang <jiada_wang at mentor.com>
> ---
>  arch/arm/mach-imx/clk-pllv3.c | 72 +++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 66 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/mach-imx/clk-pllv3.c b/arch/arm/mach-imx/clk-pllv3.c
> index 6136405..f77edd6 100644
> --- a/arch/arm/mach-imx/clk-pllv3.c
> +++ b/arch/arm/mach-imx/clk-pllv3.c
> @@ -67,6 +67,42 @@ static int clk_pllv3_wait_lock(struct clk_pllv3 *pll)
>         return readl_relaxed(pll->base) & BM_PLL_LOCK ? 0 : -ETIMEDOUT;
>  }
>
> +static void clk_pllv3_powerdown(struct clk_pllv3 *pll)
> +{
> +       u32 val;
> +
> +       val = readl_relaxed(pll->base);
> +       val |= BM_PLL_BYPASS;
> +       writel_relaxed(val, pll->base);
> +
> +       if (pll->powerup_set)
> +               val &= ~BM_PLL_POWER;
> +       else
> +               val |= BM_PLL_POWER;
> +       writel_relaxed(val, pll->base);
> +}
> +
> +static int clk_pllv3_powerrestore(struct clk_pllv3 *pll, u32 power, u32 bypass)
> +{
> +       u32 val;
> +       int ret;
> +
> +       val = readl_relaxed(pll->base);
> +       val &= ~BM_PLL_POWER;

Shouldn't this be:
      if (pll->powerup_set)
             val |= BM_PLL_POWER;
       else
             val &= ~BM_PLL_POWER;