From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 28 Sep 2010 08:48:40 +0100
Subject: [PATCH v3 5/5] OMAP: I2C: Convert i2c driver to use PM runtime
	api's
In-Reply-To: <0680EC522D0CC943BC586913CF3768C003FF05988F@dbde02.ent.ti.com>
References: <1285078036-12789-1-git-send-email-rnayak@ti.com>
	<1285078036-12789-2-git-send-email-rnayak@ti.com>
	<1285078036-12789-3-git-send-email-rnayak@ti.com>
	<1285078036-12789-4-git-send-email-rnayak@ti.com>
	<1285078036-12789-5-git-send-email-rnayak@ti.com>
	<1285078036-12789-6-git-send-email-rnayak@ti.com>
	<20100927223645.GJ21564@trinity.fluff.org>
	<0680EC522D0CC943BC586913CF3768C003FF05981F@dbde02.ent.ti.com>
	<0680EC522D0CC943BC586913CF3768C003FF05988F@dbde02.ent.ti.com>
Message-ID: <20100928074840.GA29252@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Sep 28, 2010 at 12:29:01PM +0530, Nayak, Rajendra wrote:
> <snip>...
> > > >
> > > >  static int omap_i2c_init(struct omap_i2c_dev *dev)
> > > > @@ -356,6 +333,7 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
> > > >  	unsigned long fclk_rate = 12000000;
> > > >  	unsigned long timeout;
> > > >  	unsigned long internal_clk = 0;
> > > > +	struct clk *fclk;
> > > >
> > > >  	if (dev->rev >= OMAP_I2C_REV_2) {
> > > >  		/* Disable I2C controller before soft reset */
> > > > @@ -414,7 +392,8 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
> > > >  		 * always returns 12MHz for the functional clock, we can
> > > >  		 * do this bit unconditionally.
> > > >  		 */
> > > > -		fclk_rate = clk_get_rate(dev->fclk);
> > > > +		fclk = clk_get(dev->dev, "fck");
> > > > +		fclk_rate = clk_get_rate(fclk);
> > > >
> > > >  		/* TRM for 5912 says the I2C clock must be prescaled to be
> > > >  		 * between 7 - 12 MHz. The XOR input clock is typically
> > > > @@ -443,7 +422,8 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
> > > >  			internal_clk = 9600;
> > > >  		else
> > > >  			internal_clk = 4000;
> > > > -		fclk_rate = clk_get_rate(dev->fclk) / 1000;
> > > > +		fclk = clk_get(dev->dev, "fck");
> > > > +		fclk_rate = clk_get_rate(fclk) / 1000;
> > >
> > > You don't put the clk after getting it and using it once?
> > 
> > clk_get needs an equivalent clk_put and not clk_get_rate. clk_get_rate
> > is used to merely know the existing rate of the clock.
> 
> Sorry, I guess you did mean the clk_get above the clk_get_rate does not have
> an equivalent clk_put.
> I could put a clk_put for readability, but a clk_put on OMAP actually does map
> to an empty function.
> See arch/arm/plat-omap/include/plat/clkdev.h
> clk_get merely returns a pointer to the clk struct and does not do any usecounting,
> hence a clk_put does not do anything.

That's no reason to avoid using it.