From: Stephen Boyd <sboyd@kernel.org>
To: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: linux-kernel@vger.kernel.org,
Amarula patchwork <linux-amarula@amarulasolutions.com>,
michael@amarulasolutions.com, kernel test robot <lkp@intel.com>,
Allison Randal <allison@lohutok.net>,
Miaoqian Lin <linmq006@gmail.com>,
Michael Turquette <mturquette@baylibre.com>,
Tero Kristo <kristo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Tony Lindgren <tony@atomide.com>,
linux-clk@vger.kernel.org, linux-omap@vger.kernel.org
Subject: Re: [PATCH v2] clk: ti: dra7-atl: don't allocate `parent_names' variable
Date: Tue, 01 Nov 2022 11:35:11 -0700 [thread overview]
Message-ID: <20221101183513.C63E4C433C1@smtp.kernel.org> (raw)
In-Reply-To: <CABGWkvp1iMN-4XDN_ifg6uyvQbpRzNyat_eDziWY75Cf_hCpQw@mail.gmail.com>
Quoting Dario Binacchi (2022-10-30 06:00:46)
>
> I tried to test your suggestions on another platform (I don't have the
> hw to test the driver change) but if I
> don't add pdata.name = of_clk_get_parent_name () the board boot up fails.
>
> As far I can see from the clk_core_populate_parent_map()
>
> ....
> /* Copy everything over because it might be __initdata */
> for (i = 0, parent = parents; i < num_parents; i++, parent++) {
> parent->index = -1;
> if (parent_names) {
> /* throw a WARN if any entries are NULL */
> WARN(!parent_names[i],
> "%s: invalid NULL in %s's .parent_names\n",
> __func__, core->name);
> ret = clk_cpy_name(&parent->name, parent_names[i],
> true);
> } else if (parent_data) {
> parent->hw = parent_data[i].hw;
> parent->index = parent_data[i].index;
> ret = clk_cpy_name(&parent->fw_name,
> parent_data[i].fw_name, false);
> if (!ret)
> ret = clk_cpy_name(&parent->name,
> parent_data[i].name,
> false);
> ...
>
>
> The function clk_cpy_name() is called with the parameter "mus_exist"
> to true in the path "parent_names" and false
> in the path "parent_data". Therefore, in the path "parent_data" it is
> allowed that parent-> name is not set.
> In doing so, therefore, the change would not even be backward compatible.
>
> So, IMHO, there are 2 possible options:
> 1 okay to use parent_data, but we keep using of_clk_get_parent_name
> () to set parent_data::name.
> 2 okay to use the version v2 of the patch.
>
> What do you think?
I am confused.
The struct clk_parent_data::name being used is whatever string is
returned by of_clk_get_parent_name(node, 0). That is the same as setting
struct clk_parent_data::index to 0, and not assigning the 'name' or
'fw_name' field of the parent data structure. This is a compatible
change because of_clk_get_parent_name() is getting the name of the clk
in 'clocks' for 'node' at index 0. Using the index 0 in clk_parent_data
tells clk framework that the parent of the clk being registered is the
clk in 'clocks' for the 'dev->node' that is passed in during
clk_register(). If you don't have a device pointer, use
of_clk_hw_register() to pass 'node' directly. It looks like you will
have to do that in this case to get the node pointer registered with
this clk.
prev parent reply other threads:[~2022-11-01 18:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 16:03 [PATCH v2] clk: ti: dra7-atl: don't allocate `parent_names' variable Dario Binacchi
2022-10-28 0:27 ` Stephen Boyd
2022-10-30 13:00 ` Dario Binacchi
2022-11-01 18:35 ` Stephen Boyd [this message]
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