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From: Krzysztof Kozlowski <krzk@kernel.org>
To: Jon Hunter <jonathanh@nvidia.com>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: robh+dt@kernel.org, vireshk@kernel.org,
	devicetree@vger.kernel.org, kgene@kernel.org,
	pankaj.dubey@samsung.com,
	"linux-samsung-soc@vger.kernel.org"
	<linux-samsung-soc@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	linux-pm@vger.kernel.org,
	"Bartłomiej Żołnierkiewicz" <b.zolnierkie@samsung.com>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	linux-tegra <linux-tegra@vger.kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>
Subject: Re: [PATCH v3 2/9] soc: samsung: Convert exynos-chipid driver to use the regmap API
Date: Tue, 20 Aug 2019 21:37:29 +0200
Message-ID: <CAJKOXPf597CMx=M2JmSTWe2GzBfcHFefgzSJbJ+njZGp-WfR1A@mail.gmail.com> (raw)
In-Reply-To: <b5359603-b337-dcd8-b025-ca7dff5f4a06@nvidia.com>

On Tue, 20 Aug 2019 at 21:24, Jon Hunter <jonathanh@nvidia.com> wrote:
>
>
> On 13/08/2019 16:08, Sylwester Nawrocki 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@samsung.com>
> > ---
> > Changes since v2:
> >  - s/_EXYNOS_ASV_H/__LINU_SOC_EXYNOS_ASV_H,
> >  - removed __func__ from error log,
> >  - removed unneeded <linux/of_address.h> header inclusion.
> >
> > Changes since v1 (RFC):
> >  - new patch
> > ---
> >  drivers/soc/samsung/exynos-chipid.c       | 34 ++++++---------
> >  include/linux/soc/samsung/exynos-chipid.h | 52 +++++++++++++++++++++++
> >  2 files changed, 65 insertions(+), 21 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 bcf691f2b650..006a95feb618 100644
> > --- a/drivers/soc/samsung/exynos-chipid.c
> > +++ b/drivers/soc/samsung/exynos-chipid.c
> > @@ -9,16 +9,13 @@
> >   */
> >
> >  #include <linux/io.h>
> > +#include <linux/mfd/syscon.h>
> >  #include <linux/of.h>
> > -#include <linux/of_address.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;
> > @@ -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.

This is very old patchset, revived recently. I see that in v6 it was a
platform driver:
https://patchwork.kernel.org/patch/9134949/
Pankaj, apparently based on these comments, made it initcall... but why?

Another point is that Arnd complained there about exposing global
header and no change here - we still expose the global header, but not
with soc revisions but register internals... although it has its
purpose - other Exynos-specific drivers need to access through regmap.

Best regards,
Krzysztof

  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20190813150842eucas1p2c248537d9cd593073e12abeac2cacab5@eucas1p2.samsung.com>
2019-08-13 15:08 ` [PATCH v3 0/9] Exynos Adaptive Supply Voltage support Sylwester Nawrocki
     [not found]   ` <CGME20190813150850eucas1p2aff64b5edb49ffb6626433de1c9e58ec@eucas1p2.samsung.com>
2019-08-13 15:08     ` [PATCH v3 1/9] soc: samsung: Add exynos chipid driver support Sylwester Nawrocki
2019-08-15 18:18       ` Krzysztof Kozlowski
     [not found]   ` <CGME20190813150852eucas1p2be4c0ab5ec2c079e3daf1af24283b27c@eucas1p2.samsung.com>
2019-08-13 15:08     ` [PATCH v3 2/9] soc: samsung: Convert exynos-chipid driver to use the regmap API Sylwester Nawrocki
2019-08-15 18:22       ` Krzysztof Kozlowski
2019-08-20 19:24       ` Jon Hunter
2019-08-20 19:37         ` Krzysztof Kozlowski [this message]
2019-08-20 21:38           ` Sylwester Nawrocki
2019-08-21  7:49             ` Krzysztof Kozlowski
2019-08-21 11:51             ` Bartlomiej Zolnierkiewicz
2019-08-21 12:16               ` Krzysztof Kozlowski
2019-08-21 12:41                 ` Sylwester Nawrocki
2019-08-21 13:10                   ` Krzysztof Kozlowski
2019-08-21 13:31                 ` Bartlomiej Zolnierkiewicz
     [not found]   ` <CGME20190813150853eucas1p20257455cc323a8b78b37977b0ed4937d@eucas1p2.samsung.com>
2019-08-13 15:08     ` [PATCH v3 3/9] soc: samsung: Add Exynos Adaptive Supply Voltage driver Sylwester Nawrocki
2019-08-14 12:58       ` Krzysztof Kozlowski
     [not found]   ` <CGME20190813150854eucas1p14716609be6697222ae5795328cb2ed04@eucas1p1.samsung.com>
2019-08-13 15:08     ` [PATCH v3 4/9] ARM: EXYNOS: enable exynos_chipid for ARCH_EXYNOS Sylwester Nawrocki
2019-08-15 18:29       ` Krzysztof Kozlowski
     [not found]   ` <CGME20190813150856eucas1p1a8957cfe50e3b421ccbc3084404de43b@eucas1p1.samsung.com>
2019-08-13 15:08     ` [PATCH v3 5/9] ARM64: " Sylwester Nawrocki
2019-08-15 18:29       ` Krzysztof Kozlowski
     [not found]   ` <CGME20190813150857eucas1p1387bf381b91d8fc7d0184dec92dcdf5c@eucas1p1.samsung.com>
2019-08-13 15:08     ` [PATCH v3 6/9] ARM: EXYNOS: Enable exynos-asv driver " Sylwester Nawrocki
     [not found]   ` <CGME20190813150858eucas1p1a5fbf425753e4911c50631c3a6d34ffd@eucas1p1.samsung.com>
2019-08-13 15:08     ` [PATCH v3 7/9] soc: samsung: Update the CHIP ID DT binding documentation Sylwester Nawrocki
2019-08-14 13:00       ` Krzysztof Kozlowski
2019-08-15 18:24       ` Krzysztof Kozlowski
     [not found]   ` <CGME20190813150859eucas1p13b02bf38750c2fff277f316900c9393c@eucas1p1.samsung.com>
2019-08-13 15:08     ` [PATCH v3 8/9] ARM: dts: Add "syscon" compatible string to chipid node Sylwester Nawrocki
     [not found]   ` <CGME20190813150900eucas1p12fbf753613c727d8cb6992b6f77aca80@eucas1p1.samsung.com>
2019-08-13 15:08     ` [PATCH v3 9/9] ARM: dts: Add samsung,asv-bin property for odroidxu3-lite Sylwester Nawrocki
2019-08-14 13:03   ` [PATCH v3 0/9] Exynos Adaptive Supply Voltage support Krzysztof Kozlowski

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