[PATCH 04/29] ARM: omap: clk: use clk_prepare_enable and clk_disable_unprepare

On Friday 15 June 2012 12:41 AM, Mike Turquette wrote:

On 20120614-18:16, Rajendra Nayak wrote:

quoted

As we move to Common clk framework use clk_prepare_enable()
instead of clk_enable() and similarly clk_disable_unprepare()
instead of clk_disable()

Based on initial changes from Mike turquette.

Signed-off-by: Rajendra Nayak<redacted>

Hi Rajendra,

This change looks good except for two questions I have below, related to
calling prepare in an interrupt context.  If those are non-issues then
please add my:

Acked-by: Mike Turquette<redacted>

(or my Reviewed-by... I can never remember which one is correct)

snip

quoted

diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
index 5fb47a1..e5f8e48 100644
--- a/arch/arm/mach-omap2/display.c
+++ b/arch/arm/mach-omap2/display.c

@@ -471,7 +471,7 @@ 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();

@@ -498,7 +498,7 @@ 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;

omap_dss_reset gets used by hwmod/omap_device, right?  Does the reset
path ever get called in an interrupt context?  If so clk_prepare might
sleep, which is bad.

right, I completely missed this. Will take a look at these and others
too. thanks.

regards,
Rajendra

snip

quoted

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index bf86f7e..b46ae17 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c

@@ -693,7 +693,7 @@ static int _enable_clocks(struct omap_hwmod *oh)
  	pr_debug("omap_hwmod: %s: enabling clocks\n", oh->name);

  	if (oh->_clk)
-		clk_enable(oh->_clk);
+		clk_prepare_enable(oh->_clk);

The same question above applies to basically all of the hwmod function
changes below.  I don't know if runtime pm invokes these in an interrupt
context or not, but it is something to think about.

Regards,
Mike