Subject: [PATCH 2/5] clk: sunxi: Add support for A80 basic bus clocks

From: [email-masked] (Maxime Ripard)
Date: Fri, 17 Oct 2014 15:51:25 +0200

On Thu, Oct 16, 2014 at 08:35:49PM +0800, Chen-Yu Tsai wrote:
> On Thu, Oct 16, 2014 at 4:31 PM, Maxime Ripard
> <[email-masked]> wrote:
> > On Sun, Oct 12, 2014 at 05:40:22PM +0800, Chen-Yu Tsai wrote:
> >> The A80 SoC has 12 PLL clocks, 3 AHB clocks, 2 APB clocks, and a
> >> new "GT" bus, which I assume is some kind of data bus connecting
> >> the processor cores, memory and various busses. Also there is a
> >> bus clock for a ARM CCI400 module.
> >>
> >> As far as I can tell, the GT bus and CCI400 bus clock must be
> >> protected.
> >>
> >> This patch adds driver support for peripheral related PLLs and
> >> bus clocks on the A80. The GT and CCI400 clocks are added as well
> >> as these 2 along with the PLLs they are clocked from must not be
> >> disabled.
> >>
> >> Signed-off-by: Chen-Yu Tsai <[email-masked]>
> >> ---
> >>  Documentation/devicetree/bindings/clock/sunxi.txt |   5 +
> >>  drivers/clk/sunxi/Makefile                        |   1 +
> >>  drivers/clk/sunxi/clk-sun9i-core.c                | 272 ++++++++++++++++++++++
> >>  3 files changed, 278 insertions(+)
> >>  create mode 100644 drivers/clk/sunxi/clk-sun9i-core.c
> >>
> >> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
> >> index ed116df..7f1c486 100644
> >> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
> >> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
> >> @@ -10,14 +10,17 @@ Required properties:
> >>       "allwinner,sun4i-a10-pll1-clk" - for the main PLL clock and PLL4
> >>       "allwinner,sun6i-a31-pll1-clk" - for the main PLL clock on A31
> >>       "allwinner,sun8i-a23-pll1-clk" - for the main PLL clock on A23
> >> +     "allwinner,sun9i-a80-pll4-clk" - for the peripheral PLLs on A80
> >>       "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,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
> >>       "allwinner,sun8i-a23-axi-clk" - for the AXI clock on A23
> >>       "allwinner,sun4i-a10-axi-gates-clk" - for the AXI gates
> >>       "allwinner,sun4i-a10-ahb-clk" - for the AHB clock
> >> +     "allwinner,sun9i-a80-ahb-clk" - for the AHB bus clocks on A80
> >>       "allwinner,sun4i-a10-ahb-gates-clk" - for the AHB gates on A10
> >>       "allwinner,sun5i-a13-ahb-gates-clk" - for the AHB gates on A13
> >>       "allwinner,sun5i-a10s-ahb-gates-clk" - for the AHB gates on A10s
> >> @@ -29,6 +32,7 @@ Required properties:
> >>       "allwinner,sun4i-a10-apb0-clk" - for the APB0 clock
> >>       "allwinner,sun6i-a31-apb0-clk" - for the APB0 clock on A31
> >>       "allwinner,sun8i-a23-apb0-clk" - for the APB0 clock on A23
> >> +     "allwinner,sun9i-a80-apb0-clk" - for the APB0 bus clock on A80
> >>       "allwinner,sun4i-a10-apb0-gates-clk" - for the APB0 gates on A10
> >>       "allwinner,sun5i-a13-apb0-gates-clk" - for the APB0 gates on A13
> >>       "allwinner,sun5i-a10s-apb0-gates-clk" - for the APB0 gates on A10s
> >> @@ -36,6 +40,7 @@ Required properties:
> >>       "allwinner,sun7i-a20-apb0-gates-clk" - for the APB0 gates on A20
> >>       "allwinner,sun8i-a23-apb0-gates-clk" - for the APB0 gates on A23
> >>       "allwinner,sun4i-a10-apb1-clk" - for the APB1 clock
> >> +     "allwinner,sun9i-a80-apb1-clk" - for the APB1 bus clock on A80
> >>       "allwinner,sun4i-a10-apb1-mux-clk" - for the APB1 clock muxing
> >>       "allwinner,sun4i-a10-apb1-gates-clk" - for the APB1 gates on A10
> >>       "allwinner,sun5i-a13-apb1-gates-clk" - for the APB1 gates on A13
> >> diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
> >> index 7ddc2b5..a66953c 100644
> >> --- a/drivers/clk/sunxi/Makefile
> >> +++ b/drivers/clk/sunxi/Makefile
> >> @@ -7,6 +7,7 @@ obj-y += clk-a10-hosc.o
> >>  obj-y += clk-a20-gmac.o
> >>  obj-y += clk-mod0.o
> >>  obj-y += clk-sun8i-mbus.o
> >> +obj-y += clk-sun9i-core.o
> >>
> >>  obj-$(CONFIG_MFD_SUN6I_PRCM) += \
> >>       clk-sun6i-ar100.o clk-sun6i-apb0.o clk-sun6i-apb0-gates.o \
> >> diff --git a/drivers/clk/sunxi/clk-sun9i-core.c b/drivers/clk/sunxi/clk-sun9i-core.c
> >> new file mode 100644
> >> index 0000000..ba5f091
> >> --- /dev/null
> >> +++ b/drivers/clk/sunxi/clk-sun9i-core.c
> >> @@ -0,0 +1,272 @@
> >> +/*
> >> + * Copyright 2014 Chen-Yu Tsai
> >> + *
> >> + * Chen-Yu Tsai <[email-masked]>
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License as published by
> >> + * the Free Software Foundation; either version 2 of the License, or
> >> + * (at your option) any later version.
> >> + *
> >> + * 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-provider.h>
> >> +#include <linux/clkdev.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_address.h>
> >> +#include <linux/log2.h>
> >> +
> >> +#include "clk-factors.h"
> >> +
> >> +
> >> +/**
> >> + * sun9i_a80_get_pll4_factors() - calculates n, p, m factors for PLL1
> >> + * PLL4 rate is calculated as follows
> >> + * rate = (parent_rate * n >> p) / (m + 1);
> >> + * parent_rate is always 24Mhz
> >> + *
> >> + * p and m are named div1 and div2 in Allwinner's SDK
> >> + */
> >> +
> >> +static void sun9i_a80_get_pll4_factors(u32 *freq, u32 parent_rate,
> >> +                                    u8 *n, u8 *k, u8 *m, u8 *p)
> >> +{
> >> +     int div;
> >> +
> >> +     /* Normalize value to a 6M multiple */
> >> +     div = *freq / 6000000;
> >> +
> >> +     /* divs above 256 cannot be odd */
> >> +     if (div > 256)
> >> +             div &= ~0x1;
> >> +
> >> +     /* divs above 512 must be a multiple of 4 */
> >> +     if (div > 512)
> >> +             div &= ~0x3;
> >
> > round_up / round_down looks more readable.
> 
> OK.
> 
> >> +
> >> +     *freq = 6000000 * div;
> >
> > and here as well
> 
> This won't look pretty with round_up/round_down i think.
> This function is supposed to return the actual closest supported
> frequency, so it depends on the calculated/rounded divider from
> the previous section.

Well, if I understood your code correctly, you want to round the
frequency to 6MHz multiple if div < 256, 12MHz if div < 512 and 24MHz
otherwise right?

I'm confident it can be made prettier.

> >> +     /* we were called to round the frequency, we can now return */
> >> +     if (n == NULL)
> >> +             return;
> >> +
> >> +     /* p will be 1 for divs under 512 */
> >> +     if (div < 512)
> >> +             *p = 1;
> >> +     else
> >> +             *p = 0;
> >> +
> >> +     /* m will be 1 if div is odd */
> >> +     if (div & 1)
> >> +             *m = 1;
> >> +     else
> >> +             *m = 0;
> >> +
> >> +     /* calculate a suitable n based on m and p */
> >> +     *n = div / (*p + 1) / (*m + 1);
> >> +}
> >> +
> >> +static struct clk_factors_config sun9i_a80_pll4_config = {
> >> +     .mshift = 18,
> >> +     .mwidth = 1,
> >> +     .nshift = 8,
> >> +     .nwidth = 8,
> >> +     .pshift = 16,
> >> +     .pwidth = 1,
> >> +};
> >> +
> >> +static const struct factors_data sun9i_a80_pll4_data __initconst = {
> >> +     .enable = 31,
> >> +     .table = &sun9i_a80_pll4_config,
> >> +     .getter = sun9i_a80_get_pll4_factors,
> >> +};
> >> +
> >> +static DEFINE_SPINLOCK(sun9i_a80_pll4_lock);
> >> +
> >> +static void __init sun9i_a80_pll4_setup(struct device_node *node)
> >> +{
> >> +     sunxi_factors_register(node, &sun9i_a80_pll4_data, &sun9i_a80_pll4_lock);
> >> +}
> >> +CLK_OF_DECLARE(sun9i_a80_pll4, "allwinner,sun9i-a80-pll4-clk", sun9i_a80_pll4_setup);
> >> +
> >> +
> >> +/**
> >> + * sun9i_a80_get_gt_factors() - calculates m factor for GT
> >> + * GT rate is calculated as follows
> >> + * rate = parent_rate / (m + 1);
> >> + */
> >> +
> >> +static void sun9i_a80_get_gt_factors(u32 *freq, u32 parent_rate,
> >> +                                  u8 *n, u8 *k, u8 *m, u8 *p)
> >> +{
> >> +     u32 div;
> >> +
> >> +     if (parent_rate < *freq)
> >> +             *freq = parent_rate;
> >> +
> >> +     div = DIV_ROUND_UP(parent_rate, *freq);
> >> +
> >> +     /* maximum divider is 4 */
> >> +     if (div > 4)
> >> +             div = 4;
> >> +
> >> +     *freq = parent_rate / div;
> >> +
> >> +     /* we were called to round the frequency, we can now return */
> >> +     if (!m)
> >> +             return;
> >> +
> >> +     *m = div;
> >> +}
> >> +
> >> +static struct clk_factors_config sun9i_a80_gt_config = {
> >> +     .mshift = 0,
> >> +     .mwidth = 2,
> >> +};
> >> +
> >> +static const struct factors_data sun9i_a80_gt_data __initconst = {
> >> +     .mux = 24,
> >> +     .muxmask = BIT(1) | BIT(0),
> >> +     .table = &sun9i_a80_gt_config,
> >> +     .getter = sun9i_a80_get_gt_factors,
> >> +};
> >> +
> >> +static DEFINE_SPINLOCK(sun9i_a80_gt_lock);
> >> +
> >> +static void __init sun9i_a80_gt_setup(struct device_node *node)
> >> +{
> >> +     struct clk *gt = sunxi_factors_register(node, &sun9i_a80_gt_data,
> >> +                                             &sun9i_a80_gt_lock);
> >> +
> >> +     /* The GT bus clock needs to be always enabled */
> >> +     __clk_get(gt);
> >> +     clk_prepare_enable(gt);
> >> +}
> >> +CLK_OF_DECLARE(sun9i_a80_gt, "allwinner,sun9i-a80-gt-clk", sun9i_a80_gt_setup);
> >> +
> >> +
> >> +/**
> >> + * sun9i_a80_get_ahb_factors() - calculates p factor for AHB0/1/2
> >> + * AHB rate is calculated as follows
> >> + * rate = parent_rate >> p;
> >> + */
> >> +
> >> +static void sun9i_a80_get_ahb_factors(u32 *freq, u32 parent_rate,
> >> +                                   u8 *n, u8 *k, u8 *m, u8 *p)
> >> +{
> >> +     u32 _p;
> >> +
> >> +     if (parent_rate < *freq)
> >> +             *freq = parent_rate;
> >> +
> >> +     _p = order_base_2(DIV_ROUND_UP(parent_rate, *freq));
> >> +
> >> +     /* maximum p is 3 */
> >> +     if (_p > 3)
> >> +             _p = 3;
> >> +
> >> +     *freq = parent_rate >> _p;
> >> +
> >> +     /* we were called to round the frequency, we can now return */
> >> +     if (!p)
> >> +             return;
> >> +
> >> +     *p = _p;
> >> +}
> >> +
> >> +static struct clk_factors_config sun9i_a80_ahb_config = {
> >> +     .pshift = 0,
> >> +     .pwidth = 2,
> >> +};
> >> +
> >> +static const struct factors_data sun9i_a80_ahb_data __initconst = {
> >> +     .mux = 24,
> >> +     .muxmask = BIT(1) | BIT(0),
> >> +     .table = &sun9i_a80_ahb_config,
> >> +     .getter = sun9i_a80_get_ahb_factors,
> >> +};
> >> +
> >> +static DEFINE_SPINLOCK(sun9i_a80_ahb_lock);
> >> +
> >> +static void __init sun9i_a80_ahb_setup(struct device_node *node)
> >> +{
> >> +     sunxi_factors_register(node, &sun9i_a80_ahb_data, &sun9i_a80_ahb_lock);
> >> +}
> >> +CLK_OF_DECLARE(sun9i_a80_ahb, "allwinner,sun9i-a80-ahb-clk", sun9i_a80_ahb_setup);
> >> +
> >> +
> >> +static const struct factors_data sun9i_a80_apb0_data __initconst = {
> >> +     .mux = 24,
> >> +     .muxmask = BIT(0),
> >> +     .table = &sun9i_a80_ahb_config,
> >> +     .getter = sun9i_a80_get_ahb_factors,
> >> +};
> >> +
> >> +static DEFINE_SPINLOCK(sun9i_a80_apb0_lock);
> >> +
> >> +static void __init sun9i_a80_apb0_setup(struct device_node *node)
> >> +{
> >> +     sunxi_factors_register(node, &sun9i_a80_apb0_data, &sun9i_a80_apb0_lock);
> >> +}
> >> +CLK_OF_DECLARE(sun9i_a80_apb0, "allwinner,sun9i-a80-apb0-clk", sun9i_a80_apb0_setup);
> >> +
> >> +
> >> +/**
> >> + * sun9i_a80_get_apb1_factors() - calculates m, p factors for APB1
> >> + * APB1 rate is calculated as follows
> >> + * rate = (parent_rate >> p) / (m + 1);
> >> + */
> >> +
> >> +static void sun9i_a80_get_apb1_factors(u32 *freq, u32 parent_rate,
> >> +                                    u8 *n, u8 *k, u8 *m, u8 *p)
> >> +{
> >> +     u32 div;
> >> +     u8 calcm, calcp;
> >> +
> >> +     if (parent_rate < *freq)
> >> +             *freq = parent_rate;
> >> +
> >> +     div = DIV_ROUND_UP(parent_rate, *freq);
> >> +
> >> +     /* Highest possible divider is 256 (p = 3, m = 31) */
> >> +     if (div > 256)
> >> +             div = 256;
> >> +
> >> +     calcp = order_base_2(div);
> >> +     calcm = (parent_rate >> calcp) - 1;
> >> +     *freq = (parent_rate >> calcp) / (calcm + 1);
> >> +
> >> +     /* we were called to round the frequency, we can now return */
> >> +     if (n == NULL)
> >> +             return;
> >> +
> >> +     *m = calcm;
> >> +     *p = calcp;
> >> +}
> >> +
> >> +static struct clk_factors_config sun9i_a80_apb1_config = {
> >> +     .mshift = 0,
> >> +     .mwidth = 5,
> >> +     .pshift = 16,
> >> +     .pwidth = 2,
> >> +};
> >> +
> >> +static const struct factors_data sun9i_a80_apb1_data __initconst = {
> >> +     .mux = 24,
> >> +     .muxmask = BIT(0),
> >> +     .table = &sun9i_a80_apb1_config,
> >> +     .getter = sun9i_a80_get_apb1_factors,
> >> +};
> >> +
> >> +static DEFINE_SPINLOCK(sun9i_a80_apb1_lock);
> >> +
> >> +static void __init sun9i_a80_apb1_setup(struct device_node *node)
> >> +{
> >> +     sunxi_factors_register(node, &sun9i_a80_apb1_data, &sun9i_a80_apb1_lock);
> >> +}
> >> +CLK_OF_DECLARE(sun9i_a80_apb1, "allwinner,sun9i-a80-apb1-clk", sun9i_a80_apb1_setup);
> >> +
> >
> > Do these clocks share anything (aside from being for the A80) that
> > require them to be in the same file?
> 
> They are part of the same tree hierarchy. But otherwise no requirements.
> 
> I would put CPU plls and clocks in a different file, module clocks in another,
> and the remaining (media related) plls in yet another one.

Yep, it looks better.
Thanks!

Maxime

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