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Date: Fri, 4 Feb 2011 10:34:58 +0100 From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de> To: Andres Salomon <dilinger@...ued.net> Cc: Samuel Ortiz <sameo@...ux.intel.com>, Russell King <linux@....linux.org.uk>, Mark Brown <broonie@...nsource.wolfsonmicro.com>, linux-kernel@...r.kernel.org, Richard Purdie <rpurdie@...ys.net>, Sascha Hauer <kernel@...gutronix.de>, linux-arm-kernel@...ts.infradead.org, Liam Girdwood <lrg@...mlogic.co.uk> Subject: Re: [PATCH 15/19] mc13xxx: mfd_cell is now implicitly available to drivers Hello Andres, On Wed, Feb 02, 2011 at 08:20:15PM -0800, Andres Salomon wrote: > > No need to explicitly set the cell's platform_data/data_size. > > In this case, move the various platform_data pointers > to driver_data. All of the clients which make use of it > are also changed. > > Mfd-core makes a copy of platform_data, but driver_data keeps a pointer > to the original data. Because each cell's platform_data previously > pointed to a local (stack) variable, the various ARM mach types that set > the pdata are updated to keep the memory around. I didn't get this even after reading it 5 times. You wrote in the subject that drivers now have access to mfd_cell. I don't see where e.g. drivers/leds/leds-mc13783.c uses that?! Does this depend on some mfd-changes I don't see and this is just a first step? After reading the changes I think I understood: - You made things that were passed as platform_data before available via driver_data. - Because platform_data is copied and driver_data is not at register time, the data being platform_data cannot be __initdata or stack local anymore, so this needs fixing. In sum this results in .data becoming bigger (which is bad). And I think this patch has a conceptual problem, too. In my opionion platform_data is the point to hand over platform specific data to a driver. driver_data is something that is private to the driver and has to be considered opaque for the platform. The driver was sort of OK before ... > diff --git a/arch/arm/mach-imx/mach-mx27_3ds.c b/arch/arm/mach-imx/mach-mx27_3ds.c > index 1643315..edcecaa 100644 > --- a/arch/arm/mach-imx/mach-mx27_3ds.c > +++ b/arch/arm/mach-imx/mach-mx27_3ds.c > @@ -226,10 +226,14 @@ static struct mc13783_regulator_init_data mx27_3ds_regulators[] = { > }, > }; > > -/* MC13783 */ > -static struct mc13783_platform_data mc13783_pdata __initdata = { > +static struct mc13783_regulator_platform_data mx27_regs = { The prefix mx27 is misleading. If you want to take the machine name into account use mx27_3ds, otherwise just use mc13783_regulator_pdata or similar. (And note that "regs" isn't that good IMHO, too, as it might stand for registers, too. And even mx27_3ds_regulators would be too general. This applies to the changes below, too.) > .regulators = mx27_3ds_regulators, > .num_regulators = ARRAY_SIZE(mx27_3ds_regulators), > +}; > + > +/* MC13783 */ a very minor nitpick is you moved the comment for mx27_3ds, but not for e.g. mx31_3ds. > +static struct mc13783_platform_data mc13783_pdata __initdata = { > + .regulators = &mx27_regs, > .flags = MC13783_USE_REGULATOR, > }; > > diff --git a/arch/arm/mach-imx/mach-pcm038.c b/arch/arm/mach-imx/mach-pcm038.c > index 5056148..b5ae8cc 100644 > --- a/arch/arm/mach-imx/mach-pcm038.c > +++ b/arch/arm/mach-imx/mach-pcm038.c > @@ -262,9 +262,13 @@ static struct mc13783_regulator_init_data pcm038_regulators[] = { > }, > }; > > -static struct mc13783_platform_data pcm038_pmic = { > +static struct mc13783_regulator_platform_data pcm038_regs = { > .regulators = pcm038_regulators, > .num_regulators = ARRAY_SIZE(pcm038_regulators), > +}; > + > +static struct mc13783_platform_data pcm038_pmic = { > + .regulators = &pcm038_regs, > .flags = MC13783_USE_ADC | MC13783_USE_REGULATOR | > MC13783_USE_TOUCHSCREEN, > }; > diff --git a/arch/arm/mach-mx3/mach-mx31_3ds.c b/arch/arm/mach-mx3/mach-mx31_3ds.c > index 0d65db8..3e613ee 100644 > --- a/arch/arm/mach-mx3/mach-mx31_3ds.c > +++ b/arch/arm/mach-mx3/mach-mx31_3ds.c > @@ -156,9 +156,13 @@ static struct mc13783_regulator_init_data mx31_3ds_regulators[] = { > }; > > /* MC13783 */ > -static struct mc13783_platform_data mc13783_pdata __initdata = { > +static struct mc13783_regulator_platform_data mc13783_regs = { > .regulators = mx31_3ds_regulators, > .num_regulators = ARRAY_SIZE(mx31_3ds_regulators), > +}; > + > +static struct mc13783_platform_data mc13783_pdata __initdata = { > + .regulators = &mc13783_regs, > .flags = MC13783_USE_REGULATOR | MC13783_USE_TOUCHSCREEN, > }; > > diff --git a/arch/arm/mach-mx3/mach-mx31moboard.c b/arch/arm/mach-mx3/mach-mx31moboard.c > index 1aa8d65..424fbd9 100644 > --- a/arch/arm/mach-mx3/mach-mx31moboard.c > +++ b/arch/arm/mach-mx3/mach-mx31moboard.c > @@ -267,9 +267,13 @@ static struct mc13783_leds_platform_data moboard_leds = { > .tc2_period = MC13783_LED_PERIOD_10MS, > }; > > -static struct mc13783_platform_data moboard_pmic = { > +static struct mc13783_regulator_platform_data moboard_regs = { > .regulators = moboard_regulators, > .num_regulators = ARRAY_SIZE(moboard_regulators), > +}; > + > +static struct mc13783_platform_data moboard_pmic = { > + .regulators = &moboard_regs, > .leds = &moboard_leds, > .flags = MC13783_USE_REGULATOR | MC13783_USE_RTC | > MC13783_USE_ADC | MC13783_USE_LED, > diff --git a/drivers/leds/leds-mc13783.c b/drivers/leds/leds-mc13783.c > index f05bb08..687fb13 100644 > --- a/drivers/leds/leds-mc13783.c > +++ b/drivers/leds/leds-mc13783.c > @@ -30,6 +30,7 @@ struct mc13783_led { > struct mc13783 *master; > enum led_brightness new_brightness; > int id; > + int num_leds; > }; > > #define MC13783_REG_LED_CONTROL_0 51 > @@ -181,9 +182,9 @@ static int __devinit mc13783_led_setup(struct mc13783_led *led, int max_current) > return ret; > } > > -static int __devinit mc13783_leds_prepare(struct platform_device *pdev) > +static int __devinit mc13783_leds_prepare(struct platform_device *pdev, > + struct mc13783_leds_platform_data *pdata) > { > - struct mc13783_leds_platform_data *pdata = dev_get_platdata(&pdev->dev); > struct mc13783 *dev = dev_get_drvdata(pdev->dev.parent); > int ret = 0; > int reg = 0; > @@ -264,7 +265,7 @@ out: > > static int __devinit mc13783_led_probe(struct platform_device *pdev) > { > - struct mc13783_leds_platform_data *pdata = dev_get_platdata(&pdev->dev); > + struct mc13783_leds_platform_data *pdata = platform_get_drvdata(pdev); > struct mc13783_led_platform_data *led_cur; > struct mc13783_led *led, *led_dat; > int ret, i; > @@ -286,12 +287,15 @@ static int __devinit mc13783_led_probe(struct platform_device *pdev) > return -ENOMEM; > } > > - ret = mc13783_leds_prepare(pdev); > + ret = mc13783_leds_prepare(pdev, pdata); > if (ret) { > dev_err(&pdev->dev, "unable to init led driver\n"); > goto err_free; > } > > + /* no need to save the num of LEDs for any other elements of 'led' */ > + led[0].num_leds = pdata->num_leds; > + So for n leds you introduced n-1 useless ints. So all in all, I don't like that change, maybe just because I don't understand your motivation. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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