Subject: [PATCH v7 02/11] clk: hi3xxx: add clock support

From: [email-masked] (Mike Turquette)
Date: Wed, 21 Aug 2013 14:29:46 -0700

Quoting Haojian Zhuang (2013-08-19 19:31:04)
> Add clock support with device tree on Hisilicon SoC.
> 
> Signed-off-by: Haojian Zhuang <[email-masked]>
> Cc: Mike Turquette <[email-masked]>
> ---
>  .../devicetree/bindings/clock/hisilicon.txt        | 118 +++++++++
>  drivers/clk/Makefile                               |   1 +
>  drivers/clk/clk-hi3xxx.c                           | 272 +++++++++++++++++++++
>  3 files changed, 391 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/hisilicon.txt
>  create mode 100644 drivers/clk/clk-hi3xxx.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/hisilicon.txt b/Documentation/devicetree/bindings/clock/hisilicon.txt
> new file mode 100644
> index 0000000..e8ee618
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/hisilicon.txt
> @@ -0,0 +1,118 @@
> +Device Tree Clock bindings for arch-hi3xxx
> +
> +This binding uses the common clock binding[1].
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +
> +All the mux, gate & divider are in clock container of DTS file.
> +
> +Required properties for mux clocks:
> + - compatible : shall be "hisilicon,clk-mux".
> + - clocks : shall be the input parent clock phandle for the clock. This should
> +       be the reference clock.
> + - clock-output-names : shall be reference name.
> + - #clock-cells : from common clock binding; shall be set to 0.
> + - reg : the mux register address. It should be the offset of the container.
> + - clkmux-mask : mask bits of the mux register.
> + - clkmux-table : array of mux select bits.
> +
> +Optional properties for mux clocks:
> + - clkmux-hiword-mask : indicates that the bit[31:16] are the hiword mask
> +       of mux selected bits (bit[15:0]). The bit[15:0] is valid only when
> +       bit[31:16] is set.

Instead of putting this as a flag I'm tempted to say this should be a
separate compatible string. Any thoughts from the DT experts?

> +
> +
> +
> +Required properties for gate clocks:
> + - compatible : shall be "hisilicon,clk-gate".
> + - clocks : shall be the input parent clock phandle for the clock. This should
> +       be the reference clock.
> + - clock-output-names : shall be reference name.
> + - #clock-cells : from common clock binding; shall be set to 0.
> + - reg : the mux register address. It should be the offset of the container.
> + - clkgate : bit index to control the clock gate in the gate register.
> +
> +Optional properties for gate clocks:
> + - clkgate-inverted : it indicates that setting 0 could enable the clock gate
> +       and setting 1 could disable the clock gate.
> + - clkgate-seperated-reg : it indicates that there're three continuous
> +       registers (enable, disable & status) for the same clock gate.

I responded to this in the other thread but clkgate-separated-reg is a
bad idea. You'll need your own gate clock type which handles this
instead of pushing it into the common gate implementation. Use the
existing 'reg' property to list the registers needed by this clock.

> +
> +
> +
> +Required properties for divider clocks:
> + - compatible : shall be "hisilicon,clk-div".
> + - clocks : shall be the input parent clock phandle for the clock. This should
> +       be the reference clock.
> + - clock-output-names : shall be reference name.
> + - reg : the divider register address. It should be the offset of the
> +       container.
> + - clkdiv-mask : mask bits of the divider register.
> + - clkdiv-min : the minimum divider of the clock divider.
> + - clkdiv-max : the maximum divider of the clock divider.

Are these details necessary? Do the mask, min & max values change from
clock to clock? It's nicer to have these in the driver if possible. This
looks like building a binding from a struct, which is considered bad.

> +
> +Optional properties for divider clocks:
> + - clkdiv-hiword-mask : indicates that the bit[31:16] are the hiword mask
> +       of divider selected bits (bit[15:0]). The bit[15:0] is valid only when
> +       bit[31:16] is set.

Same here. Again you might need a different compatible string for these
types of clocks.

Regards,
Mike

> +
> +
> +
> +For example:
> +       sctrl: sctrl at fc802000 {
> +               compatible = "hisilicon,sctrl";
> +               reg = <0xfc802000 0x1000>;
> +               #address-cells = <1>;
> +               #size-cells = <0>;
> +
> +
> +               timer0_mux: timer0_mux {
> +                       compatible = "hisilicon,clk-mux";
> +                       #clock-cells = <0>;
> +                       clocks = <&osc32k &timerclk01>;
> +                       clock-output-names = "timer0_mux";
> +                       reg = <0>;
> +                       clkmux-mask = <0x8000>;
> +                       clkmux-table = <0 0x8000>;
> +               };
> +               uart0_mux: uart0_mux {
> +                       compatible = "hisilicon,clk-mux";
> +                       #clock-cells = <0>;
> +                       clocks = <&osc26m &pclk>;
> +                       clock-output-names = "uart0_mux";
> +                       reg = <0x100>;
> +                       clkmux-mask = <0x80>;
> +                       /* each item value */
> +                       clkmux-table = <0 0x80>;
> +                       clkmux-hiword-mask;
> +               };
> +               timclk0: timclk0 {
> +                       compatible = "hisilicon,clk-gate";
> +                       #clock-cells = <0>;
> +                       clocks = <&timer0_mux>;
> +                       clock-output-names = "timclk0";
> +                       clkgate-inverted;
> +                       reg = <0>;
> +                       clkgate = <16>;
> +               };
> +               timerclk01: timerclk01 {
> +                       compatible = "hisilicon,clk-gate";
> +                       #clock-cells = <0>;
> +                       clocks = <&timer_rclk01>;
> +                       clock-output-names = "timerclk01";
> +                       reg = <0x20>;
> +                       clkgate = <0>;
> +                       clkgate-seperated-reg;
> +               };
> +               mmc1_div: mmc1_div {
> +                       compatible = "hisilicon,clk-div";
> +                       #clock-cells = <0>;
> +                       clocks = <&mmc1_mux>;
> +                       clock-output-names = "mmc1_div";
> +                       reg = <0x108>;
> +                       clkdiv-mask = <0x1e0>;
> +                       clkdiv-min = <1>;
> +                       clkdiv-max = <16>;
> +                       clkdiv-hiword-mask;
> +               };
> +       };
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 7b11106..2451ce6 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_COMMON_CLK)      += clk-composite.o
>  # SoCs specific
>  obj-$(CONFIG_ARCH_BCM2835)     += clk-bcm2835.o
>  obj-$(CONFIG_ARCH_NOMADIK)     += clk-nomadik.o
> +obj-$(CONFIG_ARCH_HI3xxx)      += clk-hi3xxx.o
>  obj-$(CONFIG_ARCH_HIGHBANK)    += clk-highbank.o
>  obj-$(CONFIG_ARCH_NSPIRE)      += clk-nspire.o
>  obj-$(CONFIG_ARCH_MXS)         += mxs/
> diff --git a/drivers/clk/clk-hi3xxx.c b/drivers/clk/clk-hi3xxx.c
> new file mode 100644
> index 0000000..69dca7b
> --- /dev/null
> +++ b/drivers/clk/clk-hi3xxx.c
> @@ -0,0 +1,272 @@
> +/*
> + * Hisilicon Hi3xxx clock driver
> + *
> + * Copyright (c) 2012-2013 Hisilicon Limited.
> + * Copyright (c) 2012-2013 Linaro Limited.
> + *
> + * Author: Haojian Zhuang <[email-masked]>
> + *        Xin Li <[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.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/slab.h>
> +#include <linux/clk.h>
> +
> +struct hi3620_periclk {
> +       struct clk_hw   hw;
> +       void __iomem    *enable;        /* enable register */
> +       u32             ebits;          /* bits in enable/disable register */
> +       spinlock_t      *lock;
> +};
> +
> +static void __iomem *hi3xxx_clk_base = NULL;
> +
> +static DEFINE_SPINLOCK(hi3xxx_clk_lock);
> +
> +static const struct of_device_id hi3xxx_of_match[] = {
> +       { .compatible = "hisilicon,sctrl" },
> +};
> +
> +static void __iomem __init *hi3xxx_init_clocks(struct device_node *np)
> +{
> +       struct device_node *parent;
> +       const struct of_device_id *match;
> +       void __iomem *ret = NULL;
> +
> +       parent = of_get_parent(np);
> +       if (!parent) {
> +               pr_warn("Can't find parent node of these clocks\n");
> +               goto out;
> +       }
> +       match = of_match_node(hi3xxx_of_match, parent);
> +       if (!match) {
> +               pr_warn("Can't find the right parent\n");
> +               goto out;
> +       }
> +
> +       if (!hi3xxx_clk_base) {
> +               ret = of_iomap(parent, 0);
> +               WARN_ON(!ret);
> +               hi3xxx_clk_base = ret;
> +       } else {
> +               ret = hi3xxx_clk_base;
> +       }
> +out:
> +       return ret;
> +}
> +
> +static void __init hi3xxx_clkgate_setup(struct device_node *np)
> +{
> +       struct clk *clk;
> +       const char *clk_name, **parent_names, *name;
> +       const __be32 *prop;
> +       unsigned long flags = 0;
> +       u32 bit_idx;
> +       void __iomem *base, *reg;
> +
> +       base = hi3xxx_init_clocks(np);
> +       if (!base)
> +               goto err;
> +       if (of_property_read_string(np, "clock-output-names", &clk_name))
> +               goto err;
> +       if (of_property_read_u32(np, "clkgate", &bit_idx))
> +               goto err;
> +       prop = of_get_address(np, 0, NULL, NULL);
> +       if (!prop)
> +               goto err;
> +       reg = base + be32_to_cpu(*prop);
> +       if (of_property_read_bool(np, "clkgate-inverted"))
> +               flags |= CLK_GATE_SET_TO_DISABLE;
> +       if (of_property_read_bool(np, "clkgate-seperated-reg"))
> +               flags |= CLK_GATE_SEPERATED_REG;
> +       /* gate only has the fixed parent */
> +       parent_names = kzalloc(sizeof(char *), GFP_KERNEL);
> +       if (!parent_names)
> +               goto err;
> +       parent_names[0] = of_clk_get_parent_name(np, 0);
> +
> +       clk = clk_register_gate(NULL, clk_name, parent_names[0], 0, reg,
> +                               (u8)bit_idx, flags, &hi3xxx_clk_lock);
> +       if (IS_ERR(clk))
> +               goto err_clk;
> +       if (!of_property_read_string(np, "clock-names", &name))
> +               clk_register_clkdev(clk, name, NULL);
> +       of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +       return;
> +err_clk:
> +       kfree(parent_names);
> +err:
> +       pr_err("Fail on registering hi3xxx clkgate node.\n");
> +}
> +CLK_OF_DECLARE(hi3xxx_gate, "hisilicon,clk-gate", hi3xxx_clkgate_setup)
> +
> +static int __init hi3xxx_parse_mux(struct device_node *np,
> +                                  u8 *num_parents,
> +                                  u32 *table)
> +{
> +       int i, cnt, ret;
> +
> +       /* get the count of items in mux */
> +       for (i = 0, cnt = 0; ; i++, cnt++) {
> +               /* parent's #clock-cells property is always 0 */
> +               if (!of_parse_phandle(np, "clocks", i))
> +                       break;
> +       }
> +
> +       for (i = 0; i < cnt; i++) {
> +               if (!of_clk_get_parent_name(np, i))
> +                       return -ENOENT;
> +       }
> +       *num_parents = cnt;
> +       table = kzalloc(sizeof(u32 *) * cnt, GFP_KERNEL);
> +       if (!table)
> +               return -ENOMEM;
> +       ret = of_property_read_u32_array(np, "clkmux-table",
> +                                        table, cnt);
> +       if (ret)
> +               goto err;
> +       return 0;
> +err:
> +       kfree(table);
> +       return ret;
> +}
> +
> +static void __init hi3xxx_clkmux_setup(struct device_node *np)
> +{
> +       struct clk *clk;
> +       const char *clk_name, **parent_names = NULL;
> +       const __be32 *prop;
> +       u32 mask, *table = NULL;
> +       u8 num_parents, shift, clk_mux_flags = 0;
> +       void __iomem *reg, *base;
> +       int i, ret;
> +
> +       base = hi3xxx_init_clocks(np);
> +       if (!base)
> +               goto err;
> +       if (of_property_read_string(np, "clock-output-names", &clk_name))
> +               goto err;
> +       prop = of_get_address(np, 0, NULL, NULL);
> +       if (!prop)
> +               goto err;
> +       reg = base + be32_to_cpu(*prop);
> +       if (of_property_read_u32(np, "clkmux-mask", &mask))
> +               goto err;
> +       if (of_property_read_bool(np, "clkmux-hiword-mask"))
> +               clk_mux_flags = CLK_MUX_HIWORD_MASK;
> +
> +       ret = hi3xxx_parse_mux(np, &num_parents, table);
> +       if (ret)
> +               goto err;
> +
> +       parent_names = kzalloc(sizeof(char *) * num_parents, GFP_KERNEL);
> +       if (!parent_names)
> +               goto err_table;
> +       for (i = 0; i < num_parents; i++)
> +               parent_names[i] = of_clk_get_parent_name(np, i);
> +
> +       shift = ffs(mask) - 1;
> +       mask = mask >> shift;
> +       clk = clk_register_mux_table(NULL, clk_name, parent_names, num_parents,
> +                                    CLK_SET_RATE_PARENT, reg, shift, mask,
> +                                    clk_mux_flags, table, &hi3xxx_clk_lock);
> +       if (IS_ERR(clk))
> +               goto err_clk;
> +       of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +
> +       return;
> +err_clk:
> +       kfree(parent_names);
> +err_table:
> +       kfree(table);
> +err:
> +       pr_err("Fail on registering hi3xxx clkmux node.\n");
> +}
> +CLK_OF_DECLARE(hi3xxx_mux, "hisilicon,clk-mux", hi3xxx_clkmux_setup)
> +
> +static void __init hi3xxx_clkdiv_setup(struct device_node *np, int mode)
> +{
> +       struct clk *clk;
> +       const char *clk_name, **parent_names;
> +       const __be32 *prop;
> +       struct clk_div_table *table;
> +       unsigned int table_num;
> +       u32 min, max, mask;
> +       u8 shift, width, clk_div_flags = 0;
> +       void __iomem *reg, *base;
> +       int i;
> +
> +       base = hi3xxx_init_clocks(np);
> +       if (!base)
> +               goto err;
> +
> +       if (of_property_read_string(np, "clock-output-names", &clk_name))
> +               goto err;
> +       if (of_property_read_u32(np, "clkdiv-mask", &mask))
> +               goto err;
> +       if (of_property_read_u32(np, "clkdiv-min", &min))
> +               goto err;
> +       if (of_property_read_u32(np, "clkdiv-max", &max))
> +               goto err;
> +       if (of_property_read_bool(np, "clkdiv-hiword-mask"))
> +               clk_div_flags = CLK_DIVIDER_HIWORD_MASK;
> +
> +       prop = of_get_address(np, 0, NULL, NULL);
> +       if (!prop)
> +               goto err;
> +       reg = base + be32_to_cpu(*prop);
> +
> +       table_num = max - min + 1;
> +       table = kzalloc(sizeof(*table) * table_num, GFP_KERNEL);
> +       if (!table)
> +               goto err;
> +
> +       for (i = 0; i < table_num; i++) {
> +               table[i].div = min + i;
> +               table[i].val = table[i].div - 1;
> +       }
> +
> +       /* gate only has the fixed parent */
> +       parent_names = kzalloc(sizeof(char *), GFP_KERNEL);
> +       if (!parent_names)
> +               goto err_par;
> +       parent_names[0] = of_clk_get_parent_name(np, 0);
> +       shift = ffs(mask) - 1;
> +       width = fls(mask) - ffs(mask) + 1;
> +       clk = clk_register_divider_table(NULL, clk_name, parent_names[0], 0,
> +                                        reg, shift, width, clk_div_flags,
> +                                        table, &hi3xxx_clk_lock);
> +       if (IS_ERR(clk))
> +               goto err_clk;
> +       of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +       return;
> +err_clk:
> +       kfree(parent_names);
> +err_par:
> +       kfree(table);
> +err:
> +       pr_err("Fail on registering hi3xxx clkdiv node\n");
> +}
> +CLK_OF_DECLARE(hi3xxx_div, "hisilicon,clk-div", hi3xxx_clkdiv_setup)
> -- 
> 1.8.1.2