[PATCH v4 1/3] ARM: omap: clk: add clk_prepare and clk_unprepare
Turquette, Mike
mturquette at ti.com
Wed Aug 29 20:03:49 EDT 2012
On Wed, Aug 29, 2012 at 1:56 AM, Rajendra Nayak <rnayak at ti.com> 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 at ti.com>
Looks good to me.
Reviewed-by: Mike Turquette <mturquette at linaro.org>
> ---
> 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
>
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