> -----Original Message----- > From: Ben Dooks [mailto:ben-i2c@xxxxxxxxx] > Sent: Wednesday, September 29, 2010 5:04 AM > To: Nayak, Rajendra > Cc: Ben Dooks; Paul Walmsley; Kevin Hilman; linux-i2c@xxxxxxxxxxxxxxx; ben-linux@xxxxxxxxx; khali@xxxxxxxxxxxx; linux- > omap@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH v3 5/5] OMAP: I2C: Convert i2c driver to use PM runtime api's > > 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. I agree. There is an updated patch now posted with the clk_put's in place. > > As such, I should really go and read up all about this new runtime-pm > and hwmod stuff before further commentign on the changes. Ok. Thanks. > > > > > > > > > > > > > /* 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 > > > > > > > > > > -- > > > > > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > > > > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > > -- > > > > -- > > > > Ben > > > > > > > > Q: What's a light-year? > > > > A: One-third less calories than a regular year. > > > > > > -- > > > 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 > > > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > -- > -- > Ben > > Q: What's a light-year? > A: One-third less calories than a regular year. -- 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
