From: Tony Lindgren <tony@atomide.com> To: Sven Peter <sven@svenpeter.dev> Cc: Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org, linux-clk <linux-clk@vger.kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Hector Martin <marcan@marcan.st>, Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, Mark Kettenis <mark.kettenis@xs4all.nl>, Arnd Bergmann <arnd@kernel.org> Subject: Re: [PATCH 0/3] Apple M1 clock gate driver Date: Sun, 6 Jun 2021 08:59:20 +0300 [thread overview] Message-ID: <YLxkOIu7XAJJd0bN@atomide.com> (raw) In-Reply-To: <02176203-7f29-4ff4-933b-70235cf0dd22@www.fastmail.com> * Sven Peter <sven@svenpeter.dev> [210605 12:13]: > Hi Tony, > > On Fri, Jun 4, 2021, at 09:43, Tony Lindgren wrote: > > Hi, > > > > How about the following where you set up the gate clocks as separate > > child nodes: > > > > pmgr0: clock-controller@23b700000 { > > compatible = "apple,foo-clock-controller"; > > #clock-cells = <1>; > > reg = <0x2 0x3b700000 0x0 0x4000>; > > > > clk_uart0: clock@270 { > > compatible = "apple,t8103-gate-clock"; > > #clock-cells = <0>; > > assigned-clock-parents = <&pmgr0 APPLE_CLK_SIO>, > > <&pmgr0 APPLE_CLK_UART_P>; > > // ... > > }; > > > > }; > > > > Keep the clock controller still addressable by offset from base as discussed, > > and additionally have the driver parse and set up the child node clocks. > > Nice, I like that one even better! We can keep the internal clocks "hidden" > inside the parent node and only need to model the actual consumer clocks > as separate nodes. I guess the child nodes could also use just a clocks property above instead of assigned-clock related properties if there are no configurable source clock mux registers. > Are you aware of any clock driver that implements something similar? > I'd like to avoid reinventing the wheel if it's already been done before. I'm only aware of a partial implementation so far :) The "offset from clock controller base" approach has worked well for the TI clkctrl clocks. The clkctrl gate clocks still have the SoC specific source clock data build into the clock driver(s). That's the Documentation/devicetree/bindings/clock/ti-clkctrl.txt binding. For the clkctrl clocks, the SoC specific source clock data is in drivers/clk/ti/clk-*.c files. With the Apple dtb describing the gate clock parents, you might be able to leave out most of the SoC specific built-in driver data sounds like. Regards, Tony
WARNING: multiple messages have this Message-ID (diff)
From: Tony Lindgren <tony@atomide.com> To: Sven Peter <sven@svenpeter.dev> Cc: Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org, linux-clk <linux-clk@vger.kernel.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Hector Martin <marcan@marcan.st>, Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, Mark Kettenis <mark.kettenis@xs4all.nl>, Arnd Bergmann <arnd@kernel.org> Subject: Re: [PATCH 0/3] Apple M1 clock gate driver Date: Sun, 6 Jun 2021 08:59:20 +0300 [thread overview] Message-ID: <YLxkOIu7XAJJd0bN@atomide.com> (raw) In-Reply-To: <02176203-7f29-4ff4-933b-70235cf0dd22@www.fastmail.com> * Sven Peter <sven@svenpeter.dev> [210605 12:13]: > Hi Tony, > > On Fri, Jun 4, 2021, at 09:43, Tony Lindgren wrote: > > Hi, > > > > How about the following where you set up the gate clocks as separate > > child nodes: > > > > pmgr0: clock-controller@23b700000 { > > compatible = "apple,foo-clock-controller"; > > #clock-cells = <1>; > > reg = <0x2 0x3b700000 0x0 0x4000>; > > > > clk_uart0: clock@270 { > > compatible = "apple,t8103-gate-clock"; > > #clock-cells = <0>; > > assigned-clock-parents = <&pmgr0 APPLE_CLK_SIO>, > > <&pmgr0 APPLE_CLK_UART_P>; > > // ... > > }; > > > > }; > > > > Keep the clock controller still addressable by offset from base as discussed, > > and additionally have the driver parse and set up the child node clocks. > > Nice, I like that one even better! We can keep the internal clocks "hidden" > inside the parent node and only need to model the actual consumer clocks > as separate nodes. I guess the child nodes could also use just a clocks property above instead of assigned-clock related properties if there are no configurable source clock mux registers. > Are you aware of any clock driver that implements something similar? > I'd like to avoid reinventing the wheel if it's already been done before. I'm only aware of a partial implementation so far :) The "offset from clock controller base" approach has worked well for the TI clkctrl clocks. The clkctrl gate clocks still have the SoC specific source clock data build into the clock driver(s). That's the Documentation/devicetree/bindings/clock/ti-clkctrl.txt binding. For the clkctrl clocks, the SoC specific source clock data is in drivers/clk/ti/clk-*.c files. With the Apple dtb describing the gate clock parents, you might be able to leave out most of the SoC specific built-in driver data sounds like. Regards, Tony _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-06-06 5:59 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-24 18:27 [PATCH 0/3] Apple M1 clock gate driver Sven Peter 2021-05-24 18:27 ` Sven Peter 2021-05-24 18:27 ` [PATCH 1/3] dt-bindings: clock: add DT bindings for apple,gate-clock Sven Peter 2021-05-24 18:27 ` Sven Peter 2021-05-24 18:27 ` [PATCH 2/3] clk: add support for gate clocks on Apple SoCs Sven Peter 2021-05-24 18:27 ` Sven Peter 2021-05-26 3:09 ` Stephen Boyd 2021-05-26 3:09 ` Stephen Boyd 2021-05-30 11:17 ` Sven Peter 2021-05-30 11:17 ` Sven Peter 2021-05-24 18:27 ` [PATCH 3/3] arm64: apple: add uart gate clocks Sven Peter 2021-05-24 18:27 ` Sven Peter 2021-05-26 3:10 ` Stephen Boyd 2021-05-26 3:10 ` Stephen Boyd 2021-05-30 11:11 ` Sven Peter 2021-05-30 11:11 ` Sven Peter 2021-05-25 17:41 ` [PATCH 0/3] Apple M1 clock gate driver Rob Herring 2021-05-25 17:41 ` Rob Herring 2021-05-26 7:18 ` Tony Lindgren 2021-05-26 7:18 ` Tony Lindgren 2021-05-30 11:08 ` Sven Peter 2021-05-30 11:08 ` Sven Peter 2021-06-02 9:26 ` Tony Lindgren 2021-06-02 9:26 ` Tony Lindgren 2021-06-03 12:55 ` Sven Peter 2021-06-03 12:55 ` Sven Peter 2021-06-04 7:43 ` Tony Lindgren 2021-06-04 7:43 ` Tony Lindgren 2021-06-05 12:12 ` Sven Peter 2021-06-05 12:12 ` Sven Peter 2021-06-06 5:59 ` Tony Lindgren [this message] 2021-06-06 5:59 ` Tony Lindgren 2021-05-30 11:05 ` Sven Peter 2021-05-30 11:05 ` Sven Peter 2021-06-02 9:28 ` Tony Lindgren 2021-06-02 9:28 ` Tony Lindgren
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