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.
clk_get() should have a reference counter, and on many systems does.
This is why we ask people to put clk_put() when they don't need the
clock any more. It may not do anything on your system, but it will
set a good example to anyone copying your driver code.
As such, I should really go and read up all about this new runtime-pm
and hwmod stuff before further commentign on the changes.
> >
> > >
> > > > /* Compute prescaler divisor */
> > > > psc = fclk_rate / internal_clk;
> > > > @@ -1046,14 +1026,12 @@ omap_i2c_probe(struct platform_device *pdev)
> > > > else
> > > > dev->reg_shift = 2;
> > > >
> > > > - if ((r = omap_i2c_get_clocks(dev)) != 0)
> > > > - goto err_iounmap;
> > > > -
> > > > if (cpu_is_omap44xx())
> > > > dev->regs = (u8 *) omap4_reg_map;
> > > > else
> > > > dev->regs = (u8 *) reg_map;
> > > >
> > > > + pm_runtime_enable(&pdev->dev);
> > > > omap_i2c_unidle(dev);
> > > >
> > > > dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
> > > > @@ -1125,8 +1103,6 @@ err_free_irq:
> > > > err_unuse_clocks:
> > > > omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
> > > > omap_i2c_idle(dev);
> > > > - omap_i2c_put_clocks(dev);
> > > > -err_iounmap:
> > > > iounmap(dev->base);
> > > > err_free_mem:
> > > > platform_set_drvdata(pdev, NULL);
> > > > @@ -1148,7 +1124,6 @@ omap_i2c_remove(struct platform_device *pdev)
> > > > free_irq(dev->irq, dev);
> > > > i2c_del_adapter(&dev->adapter);
> > > > omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
> > > > - omap_i2c_put_clocks(dev);
> > > > iounmap(dev->base);
> > > > kfree(dev);
> > > > mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > > --
> > > > 1.5.4.7
> > > >
> > > > --
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> > >
> > > --
> > > --
> > > Ben
> > >
> > > Q: What's a light-year?
> > > A: One-third less calories than a regular year.
> >
> > --
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>
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--
--
Ben
Q: What's a light-year?
A: One-third less calories than a regular year.
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