linux-kernel - Re: [PATCH v1 1/5] clk: tegra: Add AHB DMA clock entry

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Date:   Wed, 27 Sep 2017 11:36:05 +0300
From:   Peter De Schrijver <pdeschrijver@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>
CC:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        "Prashant Gaikwad" <pgaikwad@...dia.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Rob Herring <robh+dt@...nel.org>,
        "Vinod Koul" <vinod.koul@...el.com>, <linux-tegra@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <dmaengine@...r.kernel.org>,
        <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/5] clk: tegra: Add AHB DMA clock entry

On Tue, Sep 26, 2017 at 05:46:01PM +0300, Dmitry Osipenko wrote:
> On 26.09.2017 12:56, Peter De Schrijver wrote:
> > On Tue, Sep 26, 2017 at 02:22:02AM +0300, Dmitry Osipenko wrote:
> >> AHB DMA presents on Tegra20/30. Add missing entries, so that driver
> >> for AHB DMA could be implemented.
> >>
> >> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
> >> ---
> >>  drivers/clk/tegra/clk-id.h           | 1 +
> >>  drivers/clk/tegra/clk-tegra-periph.c | 1 +
> >>  drivers/clk/tegra/clk-tegra20.c      | 6 ++++++
> >>  drivers/clk/tegra/clk-tegra30.c      | 2 ++
> >>  4 files changed, 10 insertions(+)
> >>
> >> diff --git a/drivers/clk/tegra/clk-id.h b/drivers/clk/tegra/clk-id.h
> >> index 689f344377a7..c1661b47bbda 100644
> >> --- a/drivers/clk/tegra/clk-id.h
> >> +++ b/drivers/clk/tegra/clk-id.h
> >> @@ -12,6 +12,7 @@ enum clk_id {
> >>  	tegra_clk_amx,
> >>  	tegra_clk_amx1,
> >>  	tegra_clk_apb2ape,
> >> +	tegra_clk_ahbdma,
> >>  	tegra_clk_apbdma,
> >>  	tegra_clk_apbif,
> >>  	tegra_clk_ape,
> >> diff --git a/drivers/clk/tegra/clk-tegra-periph.c b/drivers/clk/tegra/clk-tegra-periph.c
> >> index 848255cc0209..95a3d8c95f06 100644
> >> --- a/drivers/clk/tegra/clk-tegra-periph.c
> >> +++ b/drivers/clk/tegra/clk-tegra-periph.c
> >> @@ -823,6 +823,7 @@ static struct tegra_periph_init_data gate_clks[] = {
> >>  	GATE("timer", "clk_m", 5, 0, tegra_clk_timer, CLK_IS_CRITICAL),
> >>  	GATE("isp", "clk_m", 23, 0, tegra_clk_isp, 0),
> >>  	GATE("vcp", "clk_m", 29, 0, tegra_clk_vcp, 0),
> >> +	GATE("ahbdma", "clk_m", 33, 0, tegra_clk_ahbdma, 0),
> > 
> > Parent for this should be hclk on Tegra30 and later chips as well..
> > 
> 
> It looks like other clocks have a wrong parent too here, aren't they? Like for
> example "apbdma" should have "pclk" as a parent, isn't it?
> 

Yes. That is correct.

> >>  	GATE("apbdma", "clk_m", 34, 0, tegra_clk_apbdma, 0),
> >>  	GATE("kbc", "clk_32k", 36, TEGRA_PERIPH_ON_APB | TEGRA_PERIPH_NO_RESET, tegra_clk_kbc, 0),
> >>  	GATE("fuse", "clk_m", 39, TEGRA_PERIPH_ON_APB, tegra_clk_fuse, 0),
> >> diff --git a/drivers/clk/tegra/clk-tegra20.c b/drivers/clk/tegra/clk-tegra20.c
> >> index 837e5cbd60e9..e76c0d292ca7 100644
> >> --- a/drivers/clk/tegra/clk-tegra20.c
> >> +++ b/drivers/clk/tegra/clk-tegra20.c
> >> @@ -449,6 +449,7 @@ static struct tegra_devclk devclks[] __initdata = {
> >>  	{ .con_id = "audio", .dt_id = TEGRA20_CLK_AUDIO },
> >>  	{ .con_id = "audio_2x", .dt_id = TEGRA20_CLK_AUDIO_2X },
> >>  	{ .dev_id = "tegra20-ac97", .dt_id = TEGRA20_CLK_AC97 },
> >> +	{ .dev_id = "tegra-ahbdma", .dt_id = TEGRA20_CLK_AHBDMA },
> > 
> > This isn't needed if you use DT bindings to get the clock handle.
> > 
> 
> Yes, I added it for consistency. Shouldn't we get rid of that all legacy stuff
> already?
> 

We probably should, but we can start by not adding more :)

> >>  	{ .dev_id = "tegra-apbdma", .dt_id = TEGRA20_CLK_APBDMA },
> >>  	{ .dev_id = "rtc-tegra", .dt_id = TEGRA20_CLK_RTC },
> >>  	{ .dev_id = "timer", .dt_id = TEGRA20_CLK_TIMER },
> >> @@ -806,6 +807,11 @@ static void __init tegra20_periph_clk_init(void)
> >>  				    clk_base, 0, 3, periph_clk_enb_refcnt);
> >>  	clks[TEGRA20_CLK_AC97] = clk;
> >>  
> >> +	/* ahbdma */
> >> +	clk = tegra_clk_register_periph_gate("ahbdma", "hclk", 0, clk_base,
> >> +				    0, 33, periph_clk_enb_refcnt);
> >> +	clks[TEGRA20_CLK_AHBDMA] = clk;
> >> +
> > 
> > You can use the generic definition here if you correct the entry above.
> > 
> 
> Good point, same applies to "apbdma". Thank you for the suggestion.
> 

Indeed.

Peter.