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SubjectRe: [PATCH v3 2/9] soc: samsung: Convert exynos-chipid driver to use the regmap API
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Hi,

On 8/20/19 11:38 PM, Sylwester Nawrocki wrote:
> On 8/20/19 21:37, Krzysztof Kozlowski wrote:
>>>> diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
>
>>>> @@ -51,29 +48,24 @@ static const char * __init product_id_to_soc_id(unsigned int product_id)
>>>> int __init exynos_chipid_early_init(void)
>>>> {
>>>> struct soc_device_attribute *soc_dev_attr;
>>>> - void __iomem *exynos_chipid_base;
>>>> struct soc_device *soc_dev;
>>>> struct device_node *root;
>>>> - struct device_node *np;
>>>> + struct regmap *regmap;
>>>> u32 product_id;
>>>> u32 revision;
>>>> + int ret;
>>>>
>>>> - /* look up for chipid node */
>>>> - np = of_find_compatible_node(NULL, NULL, "samsung,exynos4210-chipid");
>>>> - if (!np)
>>>> - return -ENODEV;
>>>> -
>>>> - exynos_chipid_base = of_iomap(np, 0);
>>>> - of_node_put(np);
>>>> -
>>>> - if (!exynos_chipid_base) {
>>>> - pr_err("Failed to map SoC chipid\n");
>>>> - return -ENXIO;
>>>> + regmap = syscon_regmap_lookup_by_compatible("samsung,exynos4210-chipid");
>>>> + if (IS_ERR(regmap)) {
>>>> + pr_err("Failed to get CHIPID regmap\n");
>>>> + return PTR_ERR(regmap);
>>>> }
>>> Following this change, I am now seeing the above error on our Tegra
>>> boards where this driver is enabled. This is triggering a kernel
>>> warnings test we have to fail. Hence, I don't think that you can remove
>>> the compatible node test here, unless you have a better way to determine
>>> if this is a samsung device.
>>
>> Right, this is really wrong... I missed that it is not a probe but
>> early init. And this init will be called on every board... Probably it
>> should be converted to a regular driver.

Early initialization is needed for SoC driver to be used from within
arch/arm/mach-exynos/ and _initcall() usage is the usual way for SoC
drivers to be initialized:

drivers/soc/amlogic/meson-gx-socinfo.c
drivers/soc/amlogic/meson-mx-socinfo.c
drivers/soc/atmel/soc.c
drivers/soc/bcm/brcmstb/common.c
drivers/soc/imx/soc-imx-scu.c
drivers/soc/imx/soc-imx8.c
drivers/soc/renesas/renesas-soc.c
drivers/soc/tegra/fuse/fuse-tegra.c
drivers/soc/ux500/ux500-soc-id.c
drivers/soc/versatile/soc-integrator.c
drivers/soc/versatile/soc-integrator.c

The only SoC drivers that are regular drivers are:

drivers/soc/fsl/guts.c
drivers/soc/versatile/soc-realview.c

> I'm also inclined to have it converted to a regular driver. We already
> have "exynos-asv" driver matching on the chipid node (patch 3/9).
> The ASV patches will not be merged soon anyway, all this needs some more
> thought. Krzysztof, can we abandon the chipid patches for now? Your

chipid driver is good and useful on its own. The preferred solution
IMHO would be to just revert "soc: samsung: Convert exynos-chipid
driver to use the regmap API" commit.

> pull request doesn't appear to be merged to arm-soc yet. Sorry about
> that.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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