Re: [PATCH v2 2/6] clk: Add clock driver for AXM55xx SoC

[Anders Berg]

Hi Mike,

Any comments on this..? Could you take this upstream through your clk tree?

/Anders


On Thu, Apr 24, 2014 at 12:44 PM, Anders Berg <anders.berg@xxxxxxx> wrote:
> Add clk driver to support clock blocks found on the AXM55xx devices. The driver
> provides clock implementations for three different types of clock devices on
> the AXM55xx device: PLL clock, a clock divider and a clock mux.
>
> Signed-off-by: Anders Berg <anders.berg@xxxxxxx>
> ---
>  .../devicetree/bindings/clock/clk-axxia.txt        |  88 +++++++
>  drivers/clk/Makefile                               |   1 +
>  drivers/clk/clk-axxia.c                            | 281 +++++++++++++++++++++
>  3 files changed, 370 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/clk-axxia.txt
>  create mode 100644 drivers/clk/clk-axxia.c
>
> diff --git a/Documentation/devicetree/bindings/clock/clk-axxia.txt b/Documentation/devicetree/bindings/clock/clk-axxia.txt
> new file mode 100644
> index 0000000..94eb840
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/clk-axxia.txt
> @@ -0,0 +1,88 @@
> +* Axxia clock driver bindings
> +
> +This document contains bindings for the Axxia PLL, clock divider and mux. The
> +binding uses the common clock binding found in:
> +
> +       Documentation/devicetree/bindings/clock/clock-bindings.txt
> +
> +* Axxia PLL
> +
> +Required properties:
> +- #clock-cells : shall be set to 0.
> +- compatible : shall be "lsi,axxia-pll-clock"
> +- clocks : parent clock phandle
> +- reg - specifies PLL control registers
> +
> +Optional properties:
> +- clock-output-names : From common clock binding.
> +
> +Example:
> +
> +       clk_ref0: clk_ref0 {
> +               compatible = "fixed-clock";
> +               #clock-cells = <0>;
> +               clock-frequency = <125000000>;
> +       };
> +
> +       clk_cpu_pll: clk_cpu_pll@2010022000 {
> +               compatible = "lsi,axxia-pll-clock";
> +               #clock-cells = <0>;
> +               clocks = <&clk_ref0>;
> +               clock-output-names = "clk_cpu_pll";
> +               reg = <0x20 0x10022000 0 0x2c>;
> +       };
> +
> +
> +* Axxia clock divider
> +
> +Required properties:
> +- #clock-cells : shall be set to 0.
> +- compatible : shall be "lsi,axxia-div-clock"
> +- clocks : parent clock phandle
> +- reg - clock divider control register
> +- lsi,bit-shift : bit position of the divider control field.
> +- lsi,bit-mask : width of the divider control field.
> +
> +Optional properties:
> +- clock-output-names : From common clock binding.
> +
> +Example:
> +
> +       clk_cpu_div: cpu {
> +               compatible = "lsi,axxia-div-clock";
> +               #clock-cells = <0>;
> +               clocks = <&clk_cpu_pll>;
> +               clock-output-names = "clk_cpu_div";
> +               reg = <0x20 0x10030008 0 0x4>;
> +               lsi,bit-shift = <0>;
> +               lsi,bit-width = <4>;
> +       };
> +
> +
> +* Axxia clock mux
> +
> +Required properties:
> +- #clock-cells : shall be set to 0.
> +- compatible : shall be "lsi,axxia-mux-clock"
> +- clocks : phandle of parent clocks (max 4)
> +- reg - clock divider control register
> +- lsi,bit-shift : bit position of the divider control field.
> +- lsi,bit-mask : width of the divider control field.
> +
> +Optional properties:
> +- clock-output-names : From common clock binding.
> +
> +Example:
> +
> +       clk_cpu: clk_cpu0@2010030000 {
> +               compatible = "lsi,axxia-mux-clock";
> +               #clock-cells = <0>;
> +               clocks = <&clk_ref0>,
> +                        <&clk_cpu_pll>,
> +                        <&clk_cpu_div>,
> +                        <&clk_cpu_div>;
> +               clock-output-names = "clk_cpu";
> +               reg = <0x20 0x10030000 0 0x4>;
> +               lsi,bit-shift = <0>;
> +               lsi,bit-width = <2>;
> +       };
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 88af4a3..a9d0626 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_COMMON_CLK)      += clk-composite.o
>  # hardware specific clock types
>  # please keep this section sorted lexicographically by file/directory path name
>  obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)    += clk-axi-clkgen.o
> +obj-$(CONFIG_ARCH_AXXIA)               += clk-axxia.o
>  obj-$(CONFIG_ARCH_BCM2835)             += clk-bcm2835.o
>  obj-$(CONFIG_ARCH_EFM32)               += clk-efm32gg.o
>  obj-$(CONFIG_ARCH_HIGHBANK)            += clk-highbank.o
> diff --git a/drivers/clk/clk-axxia.c b/drivers/clk/clk-axxia.c
> new file mode 100644
> index 0000000..996b8f2
> --- /dev/null
> +++ b/drivers/clk/clk-axxia.c
> @@ -0,0 +1,281 @@
> +/*
> + * arch/arm/mach-axxia/clock.c
> + *
> + * Provides clock implementations for three different types of clock devices on
> + * the Axxia device: PLL clock, a clock divider and a clock mux.
> + *
> + * Copyright (C) 2012 LSI
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/clk-provider.h>
> +
> +
> +static void __iomem *
> +parse_and_map_reg(struct device_node *node, u32 *shift, u32 *width)
> +{
> +       void __iomem *reg;
> +
> +       if (of_property_read_u32(node, "lsi,bit-shift", shift)) {
> +               pr_err("%s: no 'lsi,bit-shift' property\n", node->name);
> +               return NULL;
> +       }
> +
> +       if (of_property_read_u32(node, "lsi,bit-width", width)) {
> +               pr_err("%s: no 'lsi,bit-width' property\n", node->name);
> +               return NULL;
> +       }
> +
> +       reg = of_iomap(node, 0);
> +       if (!reg)
> +               pr_err("%s: failed to map register\n", node->name);
> +
> +       return reg;
> +}
> +
> +/**
> + * struct axxia_pllclk - Axxia PLL generated clock.
> + * @hw: clk_hw for the PLL
> + * @regs: Pointer to control registers
> + */
> +struct axxia_pllclk {
> +       struct clk_hw hw;
> +       void __iomem *regs;
> +};
> +
> +#define to_axxia_pll(_hw) container_of(_hw, struct axxia_pllclk, hw)
> +
> +static unsigned long
> +axxia_pllclk_recalc(struct clk_hw *hw, unsigned long parent_rate)
> +{
> +       struct axxia_pllclk *pll = to_axxia_pll(hw);
> +       unsigned long rate, fbdiv, refdiv, postdiv;
> +       u32 control;
> +
> +       control = readl(pll->regs);
> +       postdiv = ((control >> 0) & 0xf) + 1;
> +       fbdiv   = ((control >> 4) & 0xfff) + 3;
> +       refdiv  = ((control >> 16) & 0x1f) + 1;
> +       rate = (parent_rate / (refdiv * postdiv)) * fbdiv;
> +
> +       return rate;
> +}
> +
> +static const struct clk_ops clk_pll_ops = {
> +       .recalc_rate = axxia_pllclk_recalc,
> +};
> +
> +static struct clk *
> +register_axxia_pllclk(struct device *dev, const char *name,
> +                     const char *parent_name, void __iomem *regs)
> +{
> +       struct clk_init_data init;
> +       struct axxia_pllclk *pll;
> +       struct clk *clk;
> +
> +       pll = kzalloc(sizeof(*pll), GFP_KERNEL);
> +       if (!pll)
> +               return ERR_PTR(-ENOMEM);
> +
> +       init.name = name;
> +       init.ops = &clk_pll_ops;
> +       init.flags = 0;
> +       init.parent_names = &parent_name;
> +       init.num_parents = 1;
> +
> +       pll->regs = regs;
> +       pll->hw.init = &init;
> +
> +       clk = clk_register(NULL, &pll->hw);
> +       if (IS_ERR(clk))
> +               kfree(pll);
> +
> +       return clk;
> +}
> +
> +
> +/**
> + * struct axxia_divclk - Axxia clock divider
> + * @hw: clk_hw for the divider
> + * @regs: Pointer to control registers
> + */
> +struct axxia_divclk {
> +       struct clk_hw hw;
> +       void __iomem *regs;
> +       int shift;
> +       int width;
> +};
> +
> +#define to_axxia_divclk(_hw) container_of(_hw, struct axxia_divclk, hw)
> +
> +static unsigned long
> +axxia_divclk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
> +{
> +       struct axxia_divclk *divclk = to_axxia_divclk(hw);
> +       u32 ctrl, div;
> +
> +       ctrl = readl(divclk->regs);
> +       div = 1 + ((ctrl >> divclk->shift) & GENMASK(divclk->width-1, 0));
> +
> +       return parent_rate / div;
> +}
> +
> +const struct clk_ops axxia_divclk_ops = {
> +       .recalc_rate = axxia_divclk_recalc_rate,
> +};
> +
> +static struct clk *
> +register_axxia_divclk(struct device *dev, const char *name,
> +                     const char *parent_name, void __iomem *regs,
> +                     int shift, int width)
> +{
> +       struct axxia_divclk *div;
> +       struct clk *clk;
> +       struct clk_init_data init;
> +
> +       div = kzalloc(sizeof(struct axxia_divclk), GFP_KERNEL);
> +       if (!div)
> +               return ERR_PTR(-ENOMEM);
> +
> +       init.name = name;
> +       init.ops = &axxia_divclk_ops;
> +       init.flags = CLK_IS_BASIC;
> +       init.parent_names = &parent_name;
> +       init.num_parents = 1;
> +
> +       div->regs = regs;
> +       div->shift = shift;
> +       div->width = width;
> +       div->hw.init = &init;
> +
> +       /* register the clock */
> +       clk = clk_register(dev, &div->hw);
> +       if (IS_ERR(clk))
> +               kfree(div);
> +
> +       return clk;
> +}
> +
> +/**
> + * axxia_pll_clk_init - Axxia PLL clock setup function
> + * @node: pointer to device tree node
> + */
> +static void __init
> +axxia_pll_clk_init(struct device_node *node)
> +{
> +       struct clk *clk;
> +       const char *parent_name;
> +       void __iomem *regs;
> +       const char *clk_name = node->name;
> +
> +       of_property_read_string(node, "clock-output-names", &clk_name);
> +
> +       parent_name = of_clk_get_parent_name(node, 0);
> +       if (!parent_name) {
> +               pr_err("%s: no parent clock\n", node->name);
> +               return;
> +       }
> +
> +       regs = of_iomap(node, 0);
> +       if (!regs) {
> +               pr_err("%s: failed to map register\n", node->name);
> +               return;
> +       }
> +
> +       clk = register_axxia_pllclk(NULL, clk_name, parent_name, regs);
> +       if (IS_ERR(clk)) {
> +               pr_err("%s: register failed (%ld)\n", clk_name, PTR_ERR(clk));
> +               iounmap(regs);
> +               return;
> +       }
> +
> +       of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +CLK_OF_DECLARE(axxia_pll_clk, "lsi,axxia-pll-clock", axxia_pll_clk_init);
> +
> +
> +/**
> + * axxia_div_clk_init - Axxia clock divider setup function
> + * @node: device tree node for this clock
> + */
> +static void __init
> +axxia_div_clk_init(struct device_node *node)
> +{
> +       const char *parent_name;
> +       void __iomem *reg;
> +       u32 shift, width;
> +       struct clk *clk;
> +       const char *clk_name = node->name;
> +
> +       of_property_read_string(node, "clock-output-names", &clk_name);
> +
> +       parent_name = of_clk_get_parent_name(node, 0);
> +       if (!parent_name) {
> +               pr_err("%s: no parent clock\n", node->name);
> +               return;
> +       }
> +
> +       reg = parse_and_map_reg(node, &shift, &width);
> +       if (!reg)
> +               return;
> +
> +       clk = register_axxia_divclk(NULL, clk_name, parent_name, reg,
> +                                   shift, width);
> +       if (IS_ERR(clk)) {
> +               pr_err("%s: register failed (%ld)\n", clk_name, PTR_ERR(clk));
> +               iounmap(reg);
> +               return;
> +       }
> +
> +       of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +CLK_OF_DECLARE(axxia_div_clk, "lsi,axxia-div-clock", axxia_div_clk_init);
> +
> +
> +/**
> + * axxia_mux_clk_init - Clock mux setup function
> + * @node: device tree node for this clock
> + */
> +static void __init
> +axxia_mux_clk_init(struct device_node *node)
> +{
> +       void __iomem *reg;
> +       struct clk *clk;
> +       const char *parents[4];
> +       int num_parents;
> +       const char *clk_name = node->name;
> +       u32 shift, width;
> +       int i;
> +
> +       of_property_read_string(node, "clock-output-names", &clk_name);
> +
> +       for (i = 0; i < ARRAY_SIZE(parents); ++i) {
> +               parents[i] = of_clk_get_parent_name(node, i);
> +               if (!parents[i])
> +                       break;
> +       }
> +       num_parents = i;
> +
> +       reg = parse_and_map_reg(node, &shift, &width);
> +       if (!reg)
> +               return;
> +
> +       clk = clk_register_mux(NULL, clk_name, parents,
> +                              num_parents, 0, reg, shift, width,
> +                              CLK_MUX_READ_ONLY, NULL);
> +       if (IS_ERR(clk)) {
> +               pr_err("%s: register failed (%ld)\n", clk_name, PTR_ERR(clk));
> +               iounmap(reg);
> +               return;
> +       }
> +
> +       of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +CLK_OF_DECLARE(pll_mux_clock, "lsi,axxia-mux-clock", axxia_mux_clk_init);
> --
> 1.8.3.2
>
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