Re: [PATCH v4 1/3] ARM: omap: clk: add clk_prepare and clk_unprepare

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, Aug 29, 2012 at 1:56 AM, Rajendra Nayak <rnayak@xxxxxx> wrote:
> As part of Common Clk Framework (CCF) the clk_enable() operation
> was split into a clk_prepare() which could sleep, and a clk_enable()
> which should never sleep. Similarly the clk_disable() was
> split into clk_disable() and clk_unprepare(). This was
> needed to handle complex cases where in a clk gate/ungate
> would require a slow and a fast part to be implemented.
> None of the clocks below seem to be in the 'complex' clocks
> category and are just simple clocks which are enabled/disabled
> through simple register writes.
> Most of the instances also seem to be called in non-atomic
> context which means its safe to move all of those from
> using a clk_enable() to clk_prepare_enable() and clk_disable() to
> clk_disable_unprepare().
>
> For some others, mainly the ones handled through the hwmod framework
> there is a possibility that they get called in either an atomic
> or a non-atomic context.
>
> The way these get handled below work only as long as clk_prepare
> is implemented as a no-op (which is the case today) since this gets
> called very early at boot while most subsystems are unavailable.
> Hence these are marked with a *HACK* comment, which says we need
> to re-visit these once we start doing something meaningful with
> clk_prepare/clk_unprepare like doing voltage scaling or something
> that involves i2c.
>
> This is in preparation of OMAP moving to CCF.
>
> Based on initial changes from Mike turquette.
>
> Signed-off-by: Rajendra Nayak <rnayak@xxxxxx>

Looks good to me.

Reviewed-by: Mike Turquette <mturquette@xxxxxxxxxx>

> ---
>  arch/arm/mach-omap2/board-apollon.c    |    4 ++--
>  arch/arm/mach-omap2/board-h4.c         |    6 +++---
>  arch/arm/mach-omap2/board-omap4panda.c |    2 +-
>  arch/arm/mach-omap2/clock3xxx.c        |    8 ++++----
>  arch/arm/mach-omap2/display.c          |    4 ++--
>  arch/arm/mach-omap2/gpmc.c             |    2 +-
>  arch/arm/mach-omap2/omap_hwmod.c       |   27 +++++++++++++++++++++++++++
>  7 files changed, 40 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/board-apollon.c b/arch/arm/mach-omap2/board-apollon.c
> index e5fa46b..25e8f2f 100644
> --- a/arch/arm/mach-omap2/board-apollon.c
> +++ b/arch/arm/mach-omap2/board-apollon.c
> @@ -204,7 +204,7 @@ static inline void __init apollon_init_smc91x(void)
>                 return;
>         }
>
> -       clk_enable(gpmc_fck);
> +       clk_prepare_enable(gpmc_fck);
>         rate = clk_get_rate(gpmc_fck);
>
>         eth_cs = APOLLON_ETH_CS;
> @@ -248,7 +248,7 @@ static inline void __init apollon_init_smc91x(void)
>                 gpmc_cs_free(APOLLON_ETH_CS);
>         }
>  out:
> -       clk_disable(gpmc_fck);
> +       clk_disable_unprepare(gpmc_fck);
>         clk_put(gpmc_fck);
>  }
>
> diff --git a/arch/arm/mach-omap2/board-h4.c b/arch/arm/mach-omap2/board-h4.c
> index ace2048..bd08bef 100644
> --- a/arch/arm/mach-omap2/board-h4.c
> +++ b/arch/arm/mach-omap2/board-h4.c
> @@ -266,9 +266,9 @@ static inline void __init h4_init_debug(void)
>                 return;
>         }
>
> -       clk_enable(gpmc_fck);
> +       clk_prepare_enable(gpmc_fck);
>         rate = clk_get_rate(gpmc_fck);
> -       clk_disable(gpmc_fck);
> +       clk_disable_unprepare(gpmc_fck);
>         clk_put(gpmc_fck);
>
>         if (is_gpmc_muxed())
> @@ -312,7 +312,7 @@ static inline void __init h4_init_debug(void)
>                 gpmc_cs_free(eth_cs);
>
>  out:
> -       clk_disable(gpmc_fck);
> +       clk_disable_unprepare(gpmc_fck);
>         clk_put(gpmc_fck);
>  }
>
> diff --git a/arch/arm/mach-omap2/board-omap4panda.c b/arch/arm/mach-omap2/board-omap4panda.c
> index 70f6d1d..86c2201 100644
> --- a/arch/arm/mach-omap2/board-omap4panda.c
> +++ b/arch/arm/mach-omap2/board-omap4panda.c
> @@ -172,7 +172,7 @@ static void __init omap4_ehci_init(void)
>                 return;
>         }
>         clk_set_rate(phy_ref_clk, 19200000);
> -       clk_enable(phy_ref_clk);
> +       clk_prepare_enable(phy_ref_clk);
>
>         /* disable the power to the usb hub prior to init and reset phy+hub */
>         ret = gpio_request_array(panda_ehci_gpios,
> diff --git a/arch/arm/mach-omap2/clock3xxx.c b/arch/arm/mach-omap2/clock3xxx.c
> index 794d827..4c1591a 100644
> --- a/arch/arm/mach-omap2/clock3xxx.c
> +++ b/arch/arm/mach-omap2/clock3xxx.c
> @@ -64,15 +64,15 @@ void __init omap3_clk_lock_dpll5(void)
>
>         dpll5_clk = clk_get(NULL, "dpll5_ck");
>         clk_set_rate(dpll5_clk, DPLL5_FREQ_FOR_USBHOST);
> -       clk_enable(dpll5_clk);
> +       clk_prepare_enable(dpll5_clk);
>
>         /* Program dpll5_m2_clk divider for no division */
>         dpll5_m2_clk = clk_get(NULL, "dpll5_m2_ck");
> -       clk_enable(dpll5_m2_clk);
> +       clk_prepare_enable(dpll5_m2_clk);
>         clk_set_rate(dpll5_m2_clk, DPLL5_FREQ_FOR_USBHOST);
>
> -       clk_disable(dpll5_m2_clk);
> -       clk_disable(dpll5_clk);
> +       clk_disable_unprepare(dpll5_m2_clk);
> +       clk_disable_unprepare(dpll5_clk);
>         return;
>  }
>
> diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
> index af1ed7d..5a3afd2 100644
> --- a/arch/arm/mach-omap2/display.c
> +++ b/arch/arm/mach-omap2/display.c
> @@ -488,7 +488,7 @@ int omap_dss_reset(struct omap_hwmod *oh)
>
>         for (i = oh->opt_clks_cnt, oc = oh->opt_clks; i > 0; i--, oc++)
>                 if (oc->_clk)
> -                       clk_enable(oc->_clk);
> +                       clk_prepare_enable(oc->_clk);
>
>         dispc_disable_outputs();
>
> @@ -515,7 +515,7 @@ int omap_dss_reset(struct omap_hwmod *oh)
>
>         for (i = oh->opt_clks_cnt, oc = oh->opt_clks; i > 0; i--, oc++)
>                 if (oc->_clk)
> -                       clk_disable(oc->_clk);
> +                       clk_disable_unprepare(oc->_clk);
>
>         r = (c == MAX_MODULE_SOFTRESET_WAIT) ? -ETIMEDOUT : 0;
>
> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
> index b2b5759..a14d650c 100644
> --- a/arch/arm/mach-omap2/gpmc.c
> +++ b/arch/arm/mach-omap2/gpmc.c
> @@ -750,7 +750,7 @@ static int __init gpmc_init(void)
>                 BUG();
>         }
>
> -       clk_enable(gpmc_l3_clk);
> +       clk_prepare_enable(gpmc_l3_clk);
>
>         l = gpmc_read_reg(GPMC_REVISION);
>         printk(KERN_INFO "GPMC revision %d.%d\n", (l >> 4) & 0x0f, l & 0x0f);
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index 6ca8e51..fb3e110 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -683,6 +683,15 @@ static int _init_main_clk(struct omap_hwmod *oh)
>                            oh->name, oh->main_clk);
>                 return -EINVAL;
>         }
> +       /*
> +        * HACK: This needs a re-visit once clk_prepare() is implemented
> +        * to do something meaningful. Today its just a no-op.
> +        * If clk_prepare() is used at some point to do things like
> +        * voltage scaling etc, then this would have to be moved to
> +        * some point where subsystems like i2c and pmic become
> +        * available.
> +        */
> +       clk_prepare(oh->_clk);
>
>         if (!oh->_clk->clkdm)
>                 pr_warning("omap_hwmod: %s: missing clockdomain for %s.\n",
> @@ -720,6 +729,15 @@ static int _init_interface_clks(struct omap_hwmod *oh)
>                         ret = -EINVAL;
>                 }
>                 os->_clk = c;
> +               /*
> +                * HACK: This needs a re-visit once clk_prepare() is implemented
> +                * to do something meaningful. Today its just a no-op.
> +                * If clk_prepare() is used at some point to do things like
> +                * voltage scaling etc, then this would have to be moved to
> +                * some point where subsystems like i2c and pmic become
> +                * available.
> +                */
> +               clk_prepare(os->_clk);
>         }
>
>         return ret;
> @@ -747,6 +765,15 @@ static int _init_opt_clks(struct omap_hwmod *oh)
>                         ret = -EINVAL;
>                 }
>                 oc->_clk = c;
> +               /*
> +                * HACK: This needs a re-visit once clk_prepare() is implemented
> +                * to do something meaningful. Today its just a no-op.
> +                * If clk_prepare() is used at some point to do things like
> +                * voltage scaling etc, then this would have to be moved to
> +                * some point where subsystems like i2c and pmic become
> +                * available.
> +                */
> +               clk_prepare(oc->_clk);
>         }
>
>         return ret;
> --
> 1.7.9.5
>
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux