Re: [PATCH 07/11] clk: sunxi-ng: Add A80 Display Engine CCU

Chen-Yu Tsai
2017-01-27T09:26:53Z

On Fri, Jan 27, 2017 at 4:58 PM, Maxime Ripard
<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> wrote:
> On Thu, Jan 26, 2017 at 07:20:22PM +0800, Chen-Yu Tsai wrote:
>> On Thu, Jan 26, 2017 at 6:39 PM, Maxime Ripard
>> <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> wrote:
>> > Hi,
>> >
>> > On Tue, Jan 24, 2017 at 10:32:26AM +0800, Chen-Yu Tsai wrote:
>> >> Add support for the display engine clock controls found on the A80.
>> >>
>> >> Signed-off-by: Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>
>> >> ---
>> >> .../devicetree/bindings/clock/sun9i-de.txt | 28 ++
>> >> drivers/clk/sunxi-ng/Makefile | 1 +
>> >> drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c | 283 +++++++++++++++++++++
>> >> drivers/clk/sunxi-ng/ccu-sun9i-a80-de.h | 33 +++
>> >> include/dt-bindings/clock/sun9i-a80-de.h | 80 ++++++
>> >> include/dt-bindings/reset/sun9i-a80-de.h | 58 +++++
>> >> 6 files changed, 483 insertions(+)
>> >> create mode 100644 Documentation/devicetree/bindings/clock/sun9i-de.txt
>> >> create mode 100644 drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c
>> >> create mode 100644 drivers/clk/sunxi-ng/ccu-sun9i-a80-de.h
>> >> create mode 100644 include/dt-bindings/clock/sun9i-a80-de.h
>> >> create mode 100644 include/dt-bindings/reset/sun9i-a80-de.h
>> >>
>> >> diff --git a/Documentation/devicetree/bindings/clock/sun9i-de.txt b/Documentation/devicetree/bindings/clock/sun9i-de.txt
>> >> new file mode 100644
>> >> index 000000000000..3a5e6df70677
>> >> --- /dev/null
>> >> +++ b/Documentation/devicetree/bindings/clock/sun9i-de.txt
>> >> @@ -0,0 +1,28 @@
>> >> +Allwinner A80 Display Engine Clock Control Binding
>> >> +------------------------------------
>> >> +
>> >> +Required properties :
>> >> +- compatible: must contain one of the following compatibles:
>> >> + - "allwinner,sun9i-a80-de-clocks"
>> >> +
>> >> +- reg: Must contain the registers base address and length
>> >> +- clocks: phandle to the clocks feeding the display engine subsystem.
>> >> + Three are needed:
>> >> + - "mod": the display engine module clock
>> >> + - "dram": the DRAM bus clock for the system
>> >> + - "bus": the bus clock for the whole display engine subsystem
>> >> +- clock-names: Must contain the clock names described just above
>> >> +- resets: phandle to the reset control for the display engine subsystem.
>> >> +- #clock-cells : must contain 1
>> >> +- #reset-cells : must contain 1
>> >> +
>> >> +Example:
>> >> +de_clocks: clock@03000000 {
>> >> + compatible = "allwinner,sun9i-a80-de-clks";
>> >> + reg = <0x03000000 0x30>;
>> >> + clocks = <&ccu CLK_DE>, <&ccu CLK_SDRAM>, <&ccu CLK_BUS_DE>;
>> >> + clock-names = "mod", "dram", "bus";
>> >> + resets = <&ccu RST_BUS_DE>;
>> >> + #clock-cells = <1>;
>> >> + #reset-cells = <1>;
>> >> +};
>> >> diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
>> >> index 8f37ef7fb67d..6feaac0c5600 100644
>> >> --- a/drivers/clk/sunxi-ng/Makefile
>> >> +++ b/drivers/clk/sunxi-ng/Makefile
>> >> @@ -26,4 +26,5 @@ obj-$(CONFIG_SUN8I_A33_CCU) += ccu-sun8i-a33.o
>> >> obj-$(CONFIG_SUN8I_H3_CCU) += ccu-sun8i-h3.o
>> >> obj-$(CONFIG_SUN8I_V3S_CCU) += ccu-sun8i-v3s.o
>> >> obj-$(CONFIG_SUN9I_A80_CCU) += ccu-sun9i-a80.o
>> >> +obj-$(CONFIG_SUN9I_A80_CCU) += ccu-sun9i-a80-de.o
>> >> obj-$(CONFIG_SUN9I_A80_CCU) += ccu-sun9i-a80-usb.o
>> >> diff --git a/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c b/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c
>> >> new file mode 100644
>> >> index 000000000000..3fc27db0a49a
>> >> --- /dev/null
>> >> +++ b/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c
>> >> @@ -0,0 +1,283 @@
>> >> +/*
>> >> + * Copyright (c) 2016 Chen-Yu Tsai. All rights reserved.
>> >> + *
>> >> + * This software is licensed under the terms of the GNU General Public
>> >> + * License version 2, as published by the Free Software Foundation, and
>> >> + * may be copied, distributed, and modified under those terms.
>> >> + *
>> >> + * This program is distributed in the hope that it will be useful,
>> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> >> + * GNU General Public License for more details.
>> >> + */
>> >> +
>> >> +#include <linux/clk.h>
>> >> +#include <linux/clk-provider.h>
>> >> +#include <linux/of_address.h>
>> >> +#include <linux/platform_device.h>
>> >> +#include <linux/reset.h>
>> >> +
>> >> +#include "ccu_common.h"
>> >> +#include "ccu_div.h"
>> >> +#include "ccu_gate.h"
>> >> +#include "ccu_reset.h"
>> >> +
>> >> +#include "ccu-sun9i-a80-de.h"
>> >> +
>> >> +static SUNXI_CCU_GATE(fe0_clk, "fe0", "fe0-div",
>> >> + 0x00, BIT(0), 0);
>> >> +static SUNXI_CCU_GATE(fe1_clk, "fe1", "fe1-div",
>> >> + 0x00, BIT(1), 0);
>> >> +static SUNXI_CCU_GATE(fe2_clk, "fe2", "fe2-div",
>> >> + 0x00, BIT(2), 0);
>> >> +static SUNXI_CCU_GATE(iep_deu0_clk, "iep-deu0", "de",
>> >> + 0x00, BIT(4), 0);
>> >> +static SUNXI_CCU_GATE(iep_deu1_clk, "iep-deu1", "de",
>> >> + 0x00, BIT(5), 0);
>> >> +static SUNXI_CCU_GATE(be0_clk, "be0", "be0-div",
>> >> + 0x00, BIT(8), 0);
>> >> +static SUNXI_CCU_GATE(be1_clk, "be1", "be1-div",
>> >> + 0x00, BIT(9), 0);
>> >> +static SUNXI_CCU_GATE(be2_clk, "be2", "be2-div",
>> >> + 0x00, BIT(10), 0);
>> >> +static SUNXI_CCU_GATE(iep_drc0_clk, "iep-drc0", "de",
>> >> + 0x00, BIT(12), 0);
>> >> +static SUNXI_CCU_GATE(iep_drc1_clk, "iep-drc1", "de",
>> >> + 0x00, BIT(13), 0);
>> >> +static SUNXI_CCU_GATE(merge_clk, "merge", "de",
>> >> + 0x00, BIT(20), 0);
>> >> +
>> >> +static SUNXI_CCU_GATE(dram_fe0_clk, "dram-fe0", "sdram",
>> >> + 0x04, BIT(0), 0);
>> >> +static SUNXI_CCU_GATE(dram_fe1_clk, "dram-fe1", "sdram",
>> >> + 0x04, BIT(1), 0);
>> >> +static SUNXI_CCU_GATE(dram_fe2_clk, "dram-fe2", "sdram",
>> >> + 0x04, BIT(2), 0);
>> >> +static SUNXI_CCU_GATE(dram_deu0_clk, "dram-deu0", "sdram",
>> >> + 0x04, BIT(4), 0);
>> >> +static SUNXI_CCU_GATE(dram_deu1_clk, "dram-deu1", "sdram",
>> >> + 0x04, BIT(5), 0);
>> >> +static SUNXI_CCU_GATE(dram_be0_clk, "dram-be0", "sdram",
>> >> + 0x04, BIT(8), 0);
>> >> +static SUNXI_CCU_GATE(dram_be1_clk, "dram-be1", "sdram",
>> >> + 0x04, BIT(9), 0);
>> >> +static SUNXI_CCU_GATE(dram_be2_clk, "dram-be2", "sdram",
>> >> + 0x04, BIT(10), 0);
>> >> +static SUNXI_CCU_GATE(dram_drc0_clk, "dram-drc0", "sdram",
>> >> + 0x04, BIT(12), 0);
>> >> +static SUNXI_CCU_GATE(dram_drc1_clk, "dram-drc1", "sdram",
>> >> + 0x04, BIT(13), 0);
>> >> +
>> >> +static SUNXI_CCU_GATE(bus_fe0_clk, "bus-fe0", "bus-de",
>> >> + 0x08, BIT(0), 0);
>> >> +static SUNXI_CCU_GATE(bus_fe1_clk, "bus-fe1", "bus-de",
>> >> + 0x08, BIT(1), 0);
>> >> +static SUNXI_CCU_GATE(bus_fe2_clk, "bus-fe2", "bus-de",
>> >> + 0x08, BIT(2), 0);
>> >> +static SUNXI_CCU_GATE(bus_deu0_clk, "bus-deu0", "bus-de",
>> >> + 0x08, BIT(4), 0);
>> >> +static SUNXI_CCU_GATE(bus_deu1_clk, "bus-deu1", "bus-de",
>> >> + 0x08, BIT(5), 0);
>> >> +static SUNXI_CCU_GATE(bus_be0_clk, "bus-be0", "bus-de",
>> >> + 0x08, BIT(8), 0);
>> >> +static SUNXI_CCU_GATE(bus_be1_clk, "bus-be1", "bus-de",
>> >> + 0x08, BIT(9), 0);
>> >> +static SUNXI_CCU_GATE(bus_be2_clk, "bus-be2", "bus-de",
>> >> + 0x08, BIT(10), 0);
>> >> +static SUNXI_CCU_GATE(bus_drc0_clk, "bus-drc0", "bus-de",
>> >> + 0x08, BIT(12), 0);
>> >> +static SUNXI_CCU_GATE(bus_drc1_clk, "bus-drc1", "bus-de",
>> >> + 0x08, BIT(13), 0);
>> >> +
>> >> +static SUNXI_CCU_M(fe0_div_clk, "fe0-div", "de", 0x20, 0, 4, 0);
>> >> +static SUNXI_CCU_M(fe1_div_clk, "fe1-div", "de", 0x20, 4, 4, 0);
>> >> +static SUNXI_CCU_M(fe2_div_clk, "fe2-div", "de", 0x20, 8, 4, 0);
>> >> +static SUNXI_CCU_M(be0_div_clk, "be0-div", "de", 0x20, 16, 4, 0);
>> >> +static SUNXI_CCU_M(be1_div_clk, "be1-div", "de", 0x20, 20, 4, 0);
>> >> +static SUNXI_CCU_M(be2_div_clk, "be2-div", "de", 0x20, 24, 4, 0);
>> >
>> > I couldn't find any documentation for this CCU.
>>
>> I dug this up in the released Allwinner kernel.
>>
>> > What are those clocks for, and how the display engine should be using
>> > (ie, which one is it expecting to drive / ungate / etc.)
>>
>> Allwinner basically put all DE-related clock controls into a
>> separate module. In here, as the names above suggest, we have
>> bus gates, dram gates, and module clocks for each part of the
>> display pipeline. As with older SoCs that have DE 1.0, each
>> module should ungate and use the clocks related to them.
>>
>> I'll put something like the above in the commit message.
>
> So the module clocks are a combination of a divider and a clock?

Correct. Some have dividers, some don't.

> And I'm guessing the reason you separated them is because they belong
> in a different register.

Correct. Trying to support them within one clock would be a big
deviation from what sunxi-ng currently supports. I left the
divider clocks at the end of the list, and aren't exported to
dt either. So if we really want to get rid of those intermediate
divider clocks, we can do so later without affecting the exposed
interface.

Regards
ChenYu

> Maxime
>
> --
> Maxime Ripard, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com