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Date: Fri, 25 Jan 2013 09:36:50 +0100 From: Gregory CLEMENT <gregory.clement@...e-electrons.com> To: Linus Walleij <linus.walleij@...aro.org> CC: Grant Likely <grant.likely@...retlab.ca>, Maxime Ripard <maxime.ripard@...e-electrons.com>, Andreas Schallenberg <Andreas.Schallenberg@...itytechnica.com>, Roland Stigge <stigge@...com.de>, Jason Cooper <jason@...edaemon.net>, Andrew Lunn <andrew@...n.ch>, Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>, Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v3 2/3] gpio: pca953x: add support for pca9505 On 01/25/2013 09:16 AM, Linus Walleij wrote: > On Tue, Jan 22, 2013 at 10:10 PM, Gregory CLEMENT > <gregory.clement@...e-electrons.com> wrote: > >> Now that pca953x driver can handle GPIO expanders with more than 32 >> bits this patch adds the support for the pca9505 which cam with 40 >> GPIOs. >> >> Signed-off-by: Gregory CLEMENT <gregory.clement@...e-electrons.com> > > Patch applied, thanks. > > But guys, this driver contains some horrific stuff, look at this: > > static int pxa_gpio_nums(void) > { > int count = 0; > > #ifdef CONFIG_ARCH_PXA > if (cpu_is_pxa25x()) { > #ifdef CONFIG_CPU_PXA26x > count = 89; > gpio_type = PXA26X_GPIO; > #elif defined(CONFIG_PXA25x) > count = 84; > gpio_type = PXA26X_GPIO; > #endif /* CONFIG_CPU_PXA26x */ > } else if (cpu_is_pxa27x()) { > count = 120; > gpio_type = PXA27X_GPIO; > } else if (cpu_is_pxa93x()) { > count = 191; > gpio_type = PXA93X_GPIO; > } else if (cpu_is_pxa3xx()) { > count = 127; > gpio_type = PXA3XX_GPIO; > } > #endif /* CONFIG_ARCH_PXA */ > > #ifdef CONFIG_ARCH_MMP > if (cpu_is_pxa168() || cpu_is_pxa910()) { > count = 127; > gpio_type = MMP_GPIO; > } else if (cpu_is_mmp2()) { > count = 191; > gpio_type = MMP_GPIO; > } > #endif /* CONFIG_ARCH_MMP */ > return count; > } > > This is totally killing all attempts at a single kernel for multiple > machines in this family. The above should not be #ifdef's but instead > use either platform data or the compatible property to figure out which > one to use. > > It's fine to introduce new compatible= strings or device names to > distinguish between these. > > As an example, in pinctrl-nomadik.c we have this: > > static const struct of_device_id nmk_pinctrl_match[] = { > { > .compatible = "stericsson,nmk_pinctrl", > .data = (void *)PINCTRL_NMK_DB8500, > }, > {}, > }; > > static const struct platform_device_id nmk_pinctrl_id[] = { > { "pinctrl-stn8815", PINCTRL_NMK_STN8815 }, > { "pinctrl-db8500", PINCTRL_NMK_DB8500 }, > { "pinctrl-db8540", PINCTRL_NMK_DB8540 }, > { } > }; > > static struct platform_driver nmk_pinctrl_driver = { > .driver = { > .owner = THIS_MODULE, > .name = "pinctrl-nomadik", > .of_match_table = nmk_pinctrl_match, > }, > .probe = nmk_pinctrl_probe, > .id_table = nmk_pinctrl_id, > }; > > > The first match is for DT boot the latter for using the platform > device name directly. > > Then in the probefunction we do: > > static int nmk_pinctrl_probe(struct platform_device *pdev) > { > const struct platform_device_id *platid = platform_get_device_id(pdev); > (...) > if (platid) > version = platid->driver_data; > else if (np) { > const struct of_device_id *match; > > match = of_match_device(nmk_pinctrl_match, &pdev->dev); > if (!match) > return -ENODEV; > version = (unsigned int) match->data; > } > (...) > if (version == PINCTRL_NMK_STN8815) > nmk_pinctrl_stn8815_init(&npct->soc); > if (version == PINCTRL_NMK_DB8500) > nmk_pinctrl_db8500_init(&npct->soc); > if (version == PINCTRL_NMK_DB8540) > nmk_pinctrl_db8540_init(&npct->soc); > } > > Surely a scheme like this must be possible to use to distinguish between > the different versions at runtime rather than using these #ifdefs? > Well, at the beginning I thought adding support for pca9505 was just a matter of a couple of lines to add. Then I realized that I need to handle the 40 bits case, and I ended up refactoring all access to the registers. So now I am on it, it seems I am volunteer to continue to improve this driver. However I won't be able to test it, the only PXA based platform I have is a Zaurus SL-C3100 which embeds a PXA270 if I remember well, but I doubt it come with gpio expander on i2c. Gregory -- 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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