Messages in this thread | | | Date | Tue, 12 Jun 2012 13:28:38 +0200 | Subject | Re: [PATCH 1/2] pinctrl/nomadik: add STn8815 ASIC support | From | Linus Walleij <> |
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On Fri, Jun 8, 2012 at 6:39 PM, Stephen Warren <swarren@wwwdotorg.org> wrote: > On 06/08/2012 03:07 AM, Linus Walleij wrote: >> This adds support for the STN8815 ASIC for the Nomadik pin >> controller. > >> diff --git a/drivers/pinctrl/pinctrl-nomadik.c b/drivers/pinctrl/pinctrl-nomadik.c > >> @@ -1717,6 +1717,8 @@ static int __devinit nmk_pinctrl_probe(struct platform_device *pdev) >> of_match_device(nmk_pinctrl_match, &pdev->dev)->data; >> >> /* Poke in other ASIC variants here */ >> + if (version == PINCTRL_NMK_STN8815) >> + nmk_pinctrl_stn8815_init(&npct->soc); >> if (version == PINCTRL_NMK_DB8500) >> nmk_pinctrl_db8500_init(&npct->soc); > > One comment that came up in other reviews is that we shouldn't have a > single driver that switches on the SoC type it's running on and then > dispatches to different ${soc}_init() functions, but rather should have > multiple separate drivers, where each probe calls some utility function > with the appropriate SoC parameterization structures/tables.
I discussed this with Arnd, the patch doesn't give the context of where this identifier comes from:
static const struct platform_device_id nmk_pinctrl_id[] = { { "pinctrl-stn8815", PINCTRL_NMK_STN8815 }, { "pinctrl-db8500", PINCTRL_NMK_DB8500 }, };
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, };
And the probe looks like so:
static int __devinit nmk_pinctrl_probe(struct platform_device *pdev) { const struct platform_device_id *platid = platform_get_device_id(pdev); (...) if (platid) version = platid->driver_data;
So the same driver handles several platform device names, then the name is used to select a variant. IIRC I asked Arnd about this and he preferred this, and I was told by Mark Brown in the past to do things this way (c.f. drivers/mfs/ab8500-core.c).
Doing it the other way is also possible but leads to a proliferation of probe() calls and struct platform_driver blocks, and result in more lines of code.
Both ways have precedents in the kernel so I actually think both are OK, there is two ways to skin this cat simply and I'm not that sensitive to which one is used.
Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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