From: Geert Uytterhoeven <geert@linux-m68k.org> To: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Cc: Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>, Jaroslav Kysela <perex@perex.cz>, ALSA Development Mailing List <alsa-devel@alsa-project.org>, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@vger.kernel.org> Subject: Re: [PATCH 3/3] ASoC: rsnd: add null CLOCKIN support Date: Wed, 26 May 2021 08:58:53 +0200 [thread overview] Message-ID: <CAMuHMdVhnKeztftOJEZhSg8bXArzUDXAmHSMPVfbMamV3ihw+g@mail.gmail.com> (raw) In-Reply-To: <87zgwimnuu.wl-kuninori.morimoto.gx@renesas.com> Hi Morimoto-san, On Wed, May 26, 2021 at 12:48 AM Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> wrote: > > I'm not such a big fan of creating dummy clocks. > > And what if a future SoC lacks two CLOCKIN pins? Then you'll try to > > register a second dummy clock with the same name, which will fail, > > presumably? > > I think current code will reuse same null_clk for these. Oh right, I missed the static clk_hw pointer. What if you unload the snd-soc-rcar.ko module? > > This should only be done when the clock does not exist, not in case > > of other errors (e.g. -EPROBE_DEFER, which isn't handled yet)? > > > > As devm_clk_get_optional() already checks for existence, you could use: > > > > struct clk *clk = devm_clk_get_optional(dev, clk_name[i]); > > if (!clk) > > clk = rsnd_adg_null_clk_get(priv); > > Ah, indeed. > Thanks. I will fix it. > > > But in light of the above (avoiding dummy clocks), it might be more > > robust to make sure all code can handle adg->clk[i] = NULL? > > The reason why I don't use adg->clk[i] = NULL is it is using this macro > > #define for_each_rsnd_clk(pos, adg, i) \ > for (i = 0; \ > (i < CLKMAX) && \ > ((pos) = adg->clk[i]); \ > i++) > > The loop will stop at (A) if it was > > adg->clk[0] = audio_clk_a; > adg->clk[1] = audio_clk_b; > (A) adg->clk[2] = NULL > adg->clk[3] = audio_clk_i; If you use this macro everywhere, that is easily handled by the following variant: #define for_each_rsnd_clk(pos, adg, i) \ for (i = 0; (pos) = adg->clk[i], i < CLKMAX; i++) \ if (pos) { \ continue; \ } else There are several existing examples of such a construct. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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From: Geert Uytterhoeven <geert@linux-m68k.org> To: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@vger.kernel.org>, ALSA Development Mailing List <alsa-devel@alsa-project.org>, Liam Girdwood <lgirdwood@gmail.com>, Rob Herring <robh+dt@kernel.org>, Mark Brown <broonie@kernel.org> Subject: Re: [PATCH 3/3] ASoC: rsnd: add null CLOCKIN support Date: Wed, 26 May 2021 08:58:53 +0200 [thread overview] Message-ID: <CAMuHMdVhnKeztftOJEZhSg8bXArzUDXAmHSMPVfbMamV3ihw+g@mail.gmail.com> (raw) In-Reply-To: <87zgwimnuu.wl-kuninori.morimoto.gx@renesas.com> Hi Morimoto-san, On Wed, May 26, 2021 at 12:48 AM Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> wrote: > > I'm not such a big fan of creating dummy clocks. > > And what if a future SoC lacks two CLOCKIN pins? Then you'll try to > > register a second dummy clock with the same name, which will fail, > > presumably? > > I think current code will reuse same null_clk for these. Oh right, I missed the static clk_hw pointer. What if you unload the snd-soc-rcar.ko module? > > This should only be done when the clock does not exist, not in case > > of other errors (e.g. -EPROBE_DEFER, which isn't handled yet)? > > > > As devm_clk_get_optional() already checks for existence, you could use: > > > > struct clk *clk = devm_clk_get_optional(dev, clk_name[i]); > > if (!clk) > > clk = rsnd_adg_null_clk_get(priv); > > Ah, indeed. > Thanks. I will fix it. > > > But in light of the above (avoiding dummy clocks), it might be more > > robust to make sure all code can handle adg->clk[i] = NULL? > > The reason why I don't use adg->clk[i] = NULL is it is using this macro > > #define for_each_rsnd_clk(pos, adg, i) \ > for (i = 0; \ > (i < CLKMAX) && \ > ((pos) = adg->clk[i]); \ > i++) > > The loop will stop at (A) if it was > > adg->clk[0] = audio_clk_a; > adg->clk[1] = audio_clk_b; > (A) adg->clk[2] = NULL > adg->clk[3] = audio_clk_i; If you use this macro everywhere, that is easily handled by the following variant: #define for_each_rsnd_clk(pos, adg, i) \ for (i = 0; (pos) = adg->clk[i], i < CLKMAX; i++) \ if (pos) { \ continue; \ } else There are several existing examples of such a construct. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
next prev parent reply other threads:[~2021-05-26 6:59 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-24 6:11 [PATCH 0/3] ASoC: rsnd: add D3 support Kuninori Morimoto 2021-05-24 6:11 ` Kuninori Morimoto 2021-05-24 6:12 ` [PATCH 1/3] ASoC: dt-bindings: renesas: rsnd: tidyup properties Kuninori Morimoto 2021-05-24 6:12 ` Kuninori Morimoto 2021-05-24 6:12 ` [PATCH 2/3] ASoC: rsnd: tidyup loop on rsnd_adg_clk_query() Kuninori Morimoto 2021-05-24 6:12 ` Kuninori Morimoto 2021-05-24 6:12 ` [PATCH 3/3] ASoC: rsnd: add null CLOCKIN support Kuninori Morimoto 2021-05-24 6:12 ` Kuninori Morimoto 2021-05-25 10:31 ` Geert Uytterhoeven 2021-05-25 10:31 ` Geert Uytterhoeven 2021-05-25 22:48 ` Kuninori Morimoto 2021-05-25 22:48 ` Kuninori Morimoto 2021-05-26 6:58 ` Geert Uytterhoeven [this message] 2021-05-26 6:58 ` Geert Uytterhoeven 2021-05-26 22:06 ` Kuninori Morimoto 2021-05-26 22:06 ` Kuninori Morimoto 2021-05-27 7:30 ` Geert Uytterhoeven 2021-05-27 7:30 ` Geert Uytterhoeven 2021-05-27 9:48 ` Mark Brown 2021-05-27 9:48 ` Mark Brown 2021-05-24 11:59 ` [PATCH 0/3] ASoC: rsnd: add D3 support Mark Brown 2021-05-24 11:59 ` Mark Brown
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