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Subject: Re: [PATCH v7 2/6] interconnect: Add generic interconnect driver for
 Exynos SoCs
To:     Sylwester Nawrocki <s.nawrocki@samsung.com>, cw00.choi@samsung.com,
        krzk@kernel.org
Cc:     devicetree@vger.kernel.org, robh+dt@kernel.org,
        a.swigon@samsung.com, myungjoo.ham@samsung.com,
        inki.dae@samsung.com, sw0312.kim@samsung.com,
        b.zolnierkie@samsung.com, m.szyprowski@samsung.com,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-samsung-soc@vger.kernel.org, dri-devel@lists.freedesktop.org
References: <20201030125149.8227-1-s.nawrocki@samsung.com>
 <CGME20201030125301eucas1p218b0e654cb4c826b05280f28836da8d9@eucas1p2.samsung.com>
 <20201030125149.8227-3-s.nawrocki@samsung.com>
From:   Georgi Djakov <georgi.djakov@linaro.org>
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Message-ID: <2f243097-7b8c-9b39-989d-a36d226ecd23@linaro.org>
Date:   Tue, 3 Nov 2020 10:11:00 +0200
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In-Reply-To: <20201030125149.8227-3-s.nawrocki@samsung.com>
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Precedence: bulk

Hi Sylwester,

Thank you for refreshing the patchset!

On 10/30/20 14:51, Sylwester Nawrocki wrote:
> This patch adds a generic interconnect driver for Exynos SoCs in order
> to provide interconnect functionality for each "samsung,exynos-bus"
> compatible device.
> 
> The SoC topology is a graph (or more specifically, a tree) and its
> edges are specified using the 'samsung,interconnect-parent' in the
> DT. Due to unspecified relative probing order, -EPROBE_DEFER may be
> propagated to ensure that the parent is probed before its children.
> 
> Each bus is now an interconnect provider and an interconnect node as
> well (cf. Documentation/interconnect/interconnect.rst), i.e. every bus
> registers itself as a node. Node IDs are not hardcoded but rather
> assigned dynamically at runtime. This approach allows for using this
> driver with various Exynos SoCs.
> 
> Frequencies requested via the interconnect API for a given node are
> propagated to devfreq using dev_pm_qos_update_request(). Please note
> that it is not an error when CONFIG_INTERCONNECT is 'n', in which
> case all interconnect API functions are no-op.
> 
> The bus-width DT property is to determine the interconnect data
> width and traslate requested bandwidth to clock frequency for each
> bus.
> 
> Signed-off-by: Artur Świgoń <a.swigon@samsung.com>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> ---
> Changes for v7:
>  - adjusted to the DT property changes: "interconnects" instead
>    of "samsung,interconnect-parent", "samsung,data-clk-ratio"
>    instead of "bus-width",
>  - adaptation to of_icc_get_from_provider() function changes
>    in v5.10-rc1.
> 
> Changes for v6:
>  - corrected of_node dereferencing in exynos_icc_get_parent()
>    function,
>  - corrected initialization of icc_node->name so as to avoid
>    direct of_node->name dereferencing,
>  - added parsing of bus-width DT property.
> 
> Changes for v5:
>  - adjust to renamed exynos,interconnect-parent-node property,
>  - use automatically generated platform device id as the interconect
>    node id instead of a now unavailable devfreq->id field,
>  - add icc_ prefix to some variables to make the code more self-commenting,
>  - use icc_nodes_remove() instead of icc_node_del() + icc_node_destroy(),
>  - adjust to exynos,interconnect-parent-node property rename to
>    samsung,interconnect-parent,
>  - converted to a separate platform driver in drivers/interconnect.
> 
> ---
>  drivers/interconnect/Kconfig         |   1 +
>  drivers/interconnect/Makefile        |   1 +
>  drivers/interconnect/exynos/Kconfig  |   6 ++
>  drivers/interconnect/exynos/Makefile |   4 +
>  drivers/interconnect/exynos/exynos.c | 198 +++++++++++++++++++++++++++++++++++
>  5 files changed, 210 insertions(+)
>  create mode 100644 drivers/interconnect/exynos/Kconfig
>  create mode 100644 drivers/interconnect/exynos/Makefile
>  create mode 100644 drivers/interconnect/exynos/exynos.c
> 
[..]
> +
> +static struct platform_driver exynos_generic_icc_driver = {
> +	.driver = {
> +		.name = "exynos-generic-icc",

I think that you will need this:
		.sync_state = icc_sync_state,

Thanks,
Georgi

> +	},
> +	.probe = exynos_generic_icc_probe,
> +	.remove = exynos_generic_icc_remove,
> +};
> +module_platform_driver(exynos_generic_icc_driver);
> +
> +MODULE_DESCRIPTION("Exynos generic interconnect driver");
> +MODULE_AUTHOR("Artur Świgoń <a.swigon@samsung.com>");
> +MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:exynos-generic-icc");
>