[PATCH v7 1/2] soc: samsung: add exynos chipid driver support

[Arnd Bergmann]

On Saturday, November 5, 2016 5:33:46 PM CET Pankaj Dubey wrote:
> Exynos SoCs have Chipid, for identification of product IDs
> and SoC revisions. This patch intends to provide initialization
> code for all these functionalities, at the same time it provides some
> sysfs entries for accessing these information to user-space.
> 
> This driver uses existing binding for exynos-chipid.
> 
> CC: Grant Likely <grant.likely at linaro.org>
> CC: Rob Herring <robh+dt at kernel.org>
> CC: Linus Walleij <linus.walleij at linaro.org>
> Signed-off-by: Pankaj Dubey <pankaj.dubey at samsung.com>
> ---
>  drivers/soc/samsung/Kconfig         |   5 ++
>  drivers/soc/samsung/Makefile        |   1 +
>  drivers/soc/samsung/exynos-chipid.c | 148 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 154 insertions(+)
>  create mode 100644 drivers/soc/samsung/exynos-chipid.c
> 
> diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
> index 2455339..f9ab858 100644
> --- a/drivers/soc/samsung/Kconfig
> +++ b/drivers/soc/samsung/Kconfig
> @@ -14,4 +14,9 @@ config EXYNOS_PM_DOMAINS
>  	bool "Exynos PM domains" if COMPILE_TEST
>  	depends on PM_GENERIC_DOMAINS || COMPILE_TEST
>  
> +config EXYNOS_CHIPID
> +	bool "Exynos Chipid controller driver" if COMPILE_TEST
> +	depends on (ARM && ARCH_EXYNOS) || ((ARM || ARM64) && COMPILE_TEST)
> +	select SOC_BUS
> +

Please add a help text.

Why is this not enabled for ARM64 EXYNOS?

> +	exynos_chipid_base = of_iomap(np, 0);
> +
> +	if (!exynos_chipid_base)
> +		return PTR_ERR(exynos_chipid_base);
> +
> +	product_id  = __raw_readl(exynos_chipid_base);
> +	revision = product_id & EXYNOS_REV_MASK;
> +	iounmap(exynos_chipid_base);

Never use __raw_readl/__raw_writel in device drivers, they are not endian
safe, and we just removed all instances for Exynos a while back.

> +	return 0;
> +}
> +early_initcall(exynos_chipid_early_init);
> 

Why is this early? Please add a code comment if it's really needed to be
an early_initcall, otherwise make it a device_initcall.

	Arnd