linux-kernel - Re: [PATCH v2 2/9] soc: samsung: Convert exynos-chipid driver to use the regmap API

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Message-ID: <CAJKOXPfLPjmjgX01UAyu_=7etUO1G7osMQDmyHVBNxF2Sdh=yA@mail.gmail.com>
Date:   Tue, 23 Jul 2019 15:01:11 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Sylwester Nawrocki <s.nawrocki@...sung.com>
Cc:     robh+dt@...nel.org, vireshk@...nel.org, devicetree@...r.kernel.org,
        kgene@...nel.org, pankaj.dubey@...sung.com,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org,
        Bartłomiej Żołnierkiewicz 
        <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH v2 2/9] soc: samsung: Convert exynos-chipid driver to use
 the regmap API

On Thu, 18 Jul 2019 at 16:31, Sylwester Nawrocki <s.nawrocki@...sung.com> wrote:
>
> Convert the driver to use regmap API in order to allow other
> drivers, like ASV, to access the CHIPID registers.
>
> This patch adds definition of selected CHIPID register offsets
> and register bit fields for Exynos5422 SoC.
>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
> ---
> Changes since v1 (RFC):
>  - new patch
> ---
>  drivers/soc/samsung/exynos-chipid.c       | 33 ++++++----------
>  include/linux/soc/samsung/exynos-chipid.h | 48 +++++++++++++++++++++++
>  2 files changed, 61 insertions(+), 20 deletions(-)
>  create mode 100644 include/linux/soc/samsung/exynos-chipid.h
>
> diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
> index 78b123ee60c0..594b00488013 100644
> --- a/drivers/soc/samsung/exynos-chipid.c
> +++ b/drivers/soc/samsung/exynos-chipid.c
> @@ -9,18 +9,16 @@
>   */
>
>  #include <linux/io.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/of.h>
>  #include <linux/of_address.h>
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
> +#include <linux/regmap.h>
>  #include <linux/slab.h>
> +#include <linux/soc/samsung/exynos-chipid.h>
>  #include <linux/sys_soc.h>
>
> -#define EXYNOS_SUBREV_MASK     (0xF << 4)
> -#define EXYNOS_MAINREV_MASK    (0xF << 0)
> -#define EXYNOS_REV_MASK                (EXYNOS_SUBREV_MASK | EXYNOS_MAINREV_MASK)
> -#define EXYNOS_MASK            0xFFFFF000
> -
>  static const struct exynos_soc_id {
>         const char *name;
>         unsigned int id;
> @@ -53,29 +51,24 @@ 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("%s: failed to get regmap\n", __func__);

Other places do not use __func__ prefix so make it consistent. Add it
in patch #1?

> +               return PTR_ERR(regmap);
>         }
>
> -       product_id = readl_relaxed(exynos_chipid_base);
> +       ret = regmap_read(regmap, EXYNOS_CHIPID_REG_PRO_ID, &product_id);
> +       if (ret < 0)
> +               return ret;
> +
>         revision = product_id & EXYNOS_REV_MASK;
> -       iounmap(exynos_chipid_base);
>
>         soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
>         if (!soc_dev_attr)
> diff --git a/include/linux/soc/samsung/exynos-chipid.h b/include/linux/soc/samsung/exynos-chipid.h
> new file mode 100644
> index 000000000000..25359d70d617
> --- /dev/null
> +++ b/include/linux/soc/samsung/exynos-chipid.h
> @@ -0,0 +1,48 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2018 Samsung Electronics Co., Ltd.
> + *           http://www.samsung.com/
> + *
> + * Exynos - CHIPID support
> + */
> +
> +#define EXYNOS_CHIPID_REG_PRO_ID       0x00
> + #define EXYNOS_SUBREV_MASK            (0xf << 4)

" #define" is unusual syntax. I think not used anywhere else. Stick to
regular one.

Best regards,
Krzysztof