Re: [PATCH 5/5] mfd: sunxi-gpadc-mfd: probe sunxi-gpadc-ts driver

Jonathan Cameron
2016-07-25T10:08:44Z

On 25 July 2016 10:51:13 BST, Maxime Ripard <maxime.ripard@free-electrons.com> wrote:
>Hi Jonathan,
>
>On Sun, Jul 24, 2016 at 12:26:56PM +0100, Jonathan Cameron wrote:
>> >> @@ -142,23 +159,45 @@ static int sunxi_gpadc_mfd_probe(struct
>platform_device *pdev)
>> >> }
>> >>
>> >> if (of_device_is_compatible(pdev->dev.of_node,
>> >> - "allwinner,sun4i-a10-ts"))
>> >> - ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> - sun4i_gpadc_mfd_cells,
>> >> - ARRAY_SIZE(sun4i_gpadc_mfd_cells), NULL,
>> >> - 0, NULL);
>> >> - else if (of_device_is_compatible(pdev->dev.of_node,
>> >> - "allwinner,sun5i-a13-ts"))
>> >> - ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> - sun5i_gpadc_mfd_cells,
>> >> - ARRAY_SIZE(sun5i_gpadc_mfd_cells), NULL,
>> >> - 0, NULL);
>> >> - else if (of_device_is_compatible(pdev->dev.of_node,
>> >> - "allwinner,sun6i-a31-ts"))
>> >> - ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> - sun6i_gpadc_mfd_cells,
>> >> - ARRAY_SIZE(sun6i_gpadc_mfd_cells), NULL,
>> >> - 0, NULL);
>> >> + "allwinner,sun4i-a10-ts")) {
>> >> + if (of_property_read_bool(pdev->dev.of_node,
>> >> + "allwinner,ts-attached"))
>> >> + ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> + sun4i_gpadc_mfd_cells_ts,
>> >> + ARRAY_SIZE(sun4i_gpadc_mfd_cells_ts),
>> >> + NULL, 0, NULL);
>> >> + else
>> >> + ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> + sun4i_gpadc_mfd_cells,
>> >> + ARRAY_SIZE(sun4i_gpadc_mfd_cells),
>> >> + NULL, 0, NULL);
>> >> + } else if (of_device_is_compatible(pdev->dev.of_node,
>> >> + "allwinner,sun5i-a13-ts")) {
>> >> + if (of_property_read_bool(pdev->dev.of_node,
>> >> + "allwinner,ts-attached"))
>> >> + ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> + sun5i_gpadc_mfd_cells_ts,
>> >> + ARRAY_SIZE(sun5i_gpadc_mfd_cells_ts),
>> >> + NULL, 0, NULL);
>> >> + else
>> >> + ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> + sun5i_gpadc_mfd_cells,
>> >> + ARRAY_SIZE(sun5i_gpadc_mfd_cells),
>> >> + NULL, 0, NULL);
>> >> + } else if (of_device_is_compatible(pdev->dev.of_node,
>> >> + "allwinner,sun6i-a31-ts")) {
>> >> + if (of_property_read_bool(pdev->dev.of_node,
>> >> + "allwinner,ts-attached"))
>> >> + ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> + sun6i_gpadc_mfd_cells_ts,
>> >> + ARRAY_SIZE(sun6i_gpadc_mfd_cells_ts),
>> >> + NULL, 0, NULL);
>> >> + else
>> >> + ret = mfd_add_devices(sunxi_gpadc_mfd_dev->dev, 0,
>> >> + sun6i_gpadc_mfd_cells,
>> >> + ARRAY_SIZE(sun6i_gpadc_mfd_cells),
>> >> + NULL, 0, NULL);
>> >> + }
>> >
>> > Please don't use any of_device_is_compatible.
>> Hi Maxime,
>>
>> Why? (Just curious...)
>
>This is completely redundant. The compatible has already been looked
>up once to match the driver, and you can associate a void * pointer to
>any compatible you register in the of_device_id array.
>
>So you can just retrieve the compatible that probed you in the first
>place, and use it's private data pointer to store whatever you want,
>without the numerous (and expensive) calls to of_device_is_compatible.
>
>It's also easier to maintain in the long term, since you can simply
>add a new field to the structure you would register there, instead of
>keeping adding more conditions.
Fair enough, now I get what you mean.

Thanks,

Jonathan
>
>Maxime

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