Re: [PATCH 2/6] clk: sunxi: Add H3 clocks support

[Maxime Ripard]

Hi,

On Sun, May 10, 2015 at 12:54:50PM +0200, Jens Kuske wrote:
> On 09/05/15 13:27, Maxime Ripard wrote:
> > On Wed, May 06, 2015 at 11:31:29AM +0200, Jens Kuske wrote:
> >> The H3 clock control unit is similar to the those of other sun8i family
> >> members like the A23.
> >>
> >> The AHB1 gates got split up into AHB1 and AHB2, with AHB2 clock source
> >> being muxable between AHB1 and PLL6/2, but still sharing gate registers.
> >> The documentation isn't totally clear about which devices belong to
> >> AHB2 now, especially USB EHIC/OHIC, so it is mostly based on Allwinner
> >> kernel source code.
> >>
> >> Signed-off-by: Jens Kuske <jenskuske@xxxxxxxxx>
> >> ---
> >>  Documentation/devicetree/bindings/clock/sunxi.txt |  7 ++++
> >>  drivers/clk/sunxi/clk-sunxi.c                     | 46 ++++++++++++++++++++++-
> >>  2 files changed, 52 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
> >> index 4fa11af..4eeb893 100644
> >> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
> >> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
> >> @@ -14,6 +14,8 @@ Required properties:
> >>  	"allwinner,sun4i-a10-pll5-clk" - for the PLL5 clock
> >>  	"allwinner,sun4i-a10-pll6-clk" - for the PLL6 clock
> >>  	"allwinner,sun6i-a31-pll6-clk" - for the PLL6 clock on A31
> >> +	"allwinner,sun8i-h3-pll6-clk" - for the PLL6 clock on H3
> >> +	"allwinner,sun8i-h3-pll8-clk" - for the PLL8 clock on H3
> >>  	"allwinner,sun9i-a80-gt-clk" - for the GT bus clock on A80
> >>  	"allwinner,sun4i-a10-cpu-clk" - for the CPU multiplexer clock
> >>  	"allwinner,sun4i-a10-axi-clk" - for the AXI clock
> >> @@ -28,8 +30,11 @@ Required properties:
> >>  	"allwinner,sun7i-a20-ahb-gates-clk" - for the AHB gates on A20
> >>  	"allwinner,sun6i-a31-ar100-clk" - for the AR100 on A31
> >>  	"allwinner,sun6i-a31-ahb1-clk" - for the AHB1 clock on A31
> >> +	"allwinner,sun8i-h3-ahb2-clk" - for the AHB2 clock on H3
> >>  	"allwinner,sun6i-a31-ahb1-gates-clk" - for the AHB1 gates on A31
> >>  	"allwinner,sun8i-a23-ahb1-gates-clk" - for the AHB1 gates on A23
> >> +	"allwinner,sun8i-h3-ahb1-gates-clk" - for the AHB1 gates on H3
> >> +	"allwinner,sun8i-h3-ahb2-gates-clk" - for the AHB2 gates on H3
> >>  	"allwinner,sun9i-a80-ahb0-gates-clk" - for the AHB0 gates on A80
> >>  	"allwinner,sun9i-a80-ahb1-gates-clk" - for the AHB1 gates on A80
> >>  	"allwinner,sun9i-a80-ahb2-gates-clk" - for the AHB2 gates on A80
> >> @@ -52,8 +57,10 @@ Required properties:
> >>  	"allwinner,sun6i-a31-apb1-gates-clk" - for the APB1 gates on A31
> >>  	"allwinner,sun7i-a20-apb1-gates-clk" - for the APB1 gates on A20
> >>  	"allwinner,sun8i-a23-apb1-gates-clk" - for the APB1 gates on A23
> >> +	"allwinner,sun8i-h3-apb1-gates-clk" - for the APB1 gates on H3
> >>  	"allwinner,sun9i-a80-apb1-gates-clk" - for the APB1 gates on A80
> >>  	"allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31
> >> +	"allwinner,sun8i-h3-apb2-gates-clk" - for the APB2 gates on H3
> >>  	"allwinner,sun8i-a23-apb2-gates-clk" - for the APB2 gates on A23
> >>  	"allwinner,sun5i-a13-mbus-clk" - for the MBUS clock on A13
> >>  	"allwinner,sun4i-a10-mmc-clk" - for the MMC clock
> >> diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
> >> index 7e1e2bd..152a1f7 100644
> >> --- a/drivers/clk/sunxi/clk-sunxi.c
> >> +++ b/drivers/clk/sunxi/clk-sunxi.c
> >> @@ -727,6 +727,12 @@ static const struct factors_data sun5i_a13_ahb_data __initconst = {
> >>  	.getter = sun5i_a13_get_ahb_factors,
> >>  };
> >>  
> >> +static const struct factors_data sun8i_h3_pll8_data __initconst = {
> >> +	.enable = 31,
> >> +	.table = &sun6i_a31_pll6_config,
> >> +	.getter = sun6i_a31_get_pll6_factors,
> >> +};
> > 
> > This looks like it's just another instance of the A31 pll6.
> > 
> > In such a case, we don't need to declare a new driver, just reuse the
> > same compatible.
> 
> If I reuse pll6 for pll8 I get errors because of the .name = "pll6x2"
> field, already existing clock or something like that.

Damn. You're obviously right...

Could you add a TODO comment on top then? just so that we know that we
need to merge this clock with pll6?

> (And pll8 doesn't even have a x2 version)

Judging by the H3 datasheet, it does.

> >>  static const struct factors_data sun4i_apb1_data __initconst = {
> >>  	.mux = 24,
> >>  	.muxmask = BIT(1) | BIT(0),
> >> @@ -777,6 +783,10 @@ static const struct mux_data sun6i_a31_ahb1_mux_data __initconst = {
> >>  	.shift = 12,
> >>  };
> >>  
> >> +static const struct mux_data sun8i_h3_ahb2_mux_data __initconst = {
> >> +	.shift = 0,
> >> +};
> >> +
> >>  static void __init sunxi_mux_clk_setup(struct device_node *node,
> >>  				       struct mux_data *data)
> >>  {
> >> @@ -892,7 +902,7 @@ static void __init sunxi_divider_clk_setup(struct device_node *node,
> >>   * sunxi_gates_clk_setup() - Setup function for leaf gates on clocks
> >>   */
> >>  
> >> -#define SUNXI_GATES_MAX_SIZE	64
> >> +#define SUNXI_GATES_MAX_SIZE	160
> >>  
> >>  struct gates_data {
> >>  	DECLARE_BITMAP(mask, SUNXI_GATES_MAX_SIZE);
> >> @@ -926,6 +936,10 @@ static const struct gates_data sun8i_a23_ahb1_gates_data __initconst = {
> >>  	.mask = {0x25386742, 0x2505111},
> >>  };
> >>  
> >> +static const struct gates_data sun8i_h3_ahb1_gates_data __initconst = {
> >> +	.mask = {0x1fbc6760, 0x00701b39, 0x00000000, 0x00000000, 0x00000081},
> >> +};
> >> +
> > 
> > Judging from the user manual, there's a few gates in those 0
> > registers, is this normal that you don't support them?
> 
> They are holes for apb1 and apb2. Which is actually pretty ugly.

Ah, right.

So I guess it's completely related to the discussion below.

> >>  static const struct gates_data sun9i_a80_ahb0_gates_data __initconst = {
> >>  	.mask = {0xF5F12B},
> >>  };
> >> @@ -938,6 +952,10 @@ static const struct gates_data sun9i_a80_ahb2_gates_data __initconst = {
> >>  	.mask = {0x9B7},
> >>  };
> >>  
> >> +static const struct gates_data sun8i_h3_ahb2_gates_data __initconst = {
> >> +	.mask = {0xe0020000},
> >> +};
> >> +
> > 
> > I don't think we should split the ahb1 and ahb2 gates here. It really
> > looks like it's the same controller.
> > 
> > The way I'm seeing it would be to have a single clock driver that
> > would handle both your ahb1 and ahb2 gates.
> > 
> > It would take two parents, ahb1 and ahb2, obviously, and would take
> > register depending on the gate w'ere registering either the ahb1 or
> > the ahb2 parent.
> > 
> > It seems like there's only a handful of devices in ahb2 anyway, so
> > that wouldn't make a very long list of devices to declare as childs of
> > ahb2.
> > 
> 
> I have thought about adding a bus_gates driver for all ahb1, ahb2, apb1
> and apb2 gates, as it is done in the user manual.
> 
> But it would need a pretty big parents array and result in big gate
> numbers in devicetree, <&bus_gates 112> for uart0 for example.
> 
> Would this be ok?

I don't see anything wrong with that, as long as we have a clear
documentation stating where that number comes from.

Maxime

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

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