Re: [PATCH v11] clk: add MOXA ART SoCs clock driver

[Mike Turquette <mturquette@linaro.org>]

Quoting Jonas Jensen (2014-01-28 03:09:11)
> MOXA ART SoCs allow to determine PLL output and APB frequencies
> by reading registers holding multiplier and divisor information.
> 
> Add a clock driver for this SoC.
> 
> Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>

Taken into clk-next.

Regards,
Mike

> ---
> 
> Notes:
>     Thanks for the replies,
>     
>     Changes since v10:
>     
>     1. add clock-specifier to DT binding description
>     2. remove local variable "rate"
>     3. add local variable "parent_name"
>     4. use clk_register_fixed_factor() instead of clk_register_fixed_rate()
>     5. remove flag CLK_IS_ROOT
>     
>     Applies to next-20140128
> 
>  .../bindings/clock/moxa,moxart-clock.txt           | 48 +++++++++++
>  drivers/clk/Makefile                               |  1 +
>  drivers/clk/clk-moxart.c                           | 97 ++++++++++++++++++++++
>  3 files changed, 146 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/moxa,moxart-clock.txt
>  create mode 100644 drivers/clk/clk-moxart.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/moxa,moxart-clock.txt b/Documentation/devicetree/bindings/clock/moxa,moxart-clock.txt
> new file mode 100644
> index 0000000..fedea84
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/moxa,moxart-clock.txt
> @@ -0,0 +1,48 @@
> +Device Tree Clock bindings for arch-moxart
> +
> +This binding uses the common clock binding[1].
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +
> +MOXA ART SoCs allow to determine PLL output and APB frequencies
> +by reading registers holding multiplier and divisor information.
> +
> +
> +PLL:
> +
> +Required properties:
> +- compatible : Must be "moxa,moxart-pll-clock"
> +- #clock-cells : Should be 0
> +- reg : Should contain registers location and length
> +- clocks : Should contain phandle + clock-specifier for the parent clock
> +
> +Optional properties:
> +- clock-output-names : Should contain clock name
> +
> +
> +APB:
> +
> +Required properties:
> +- compatible : Must be "moxa,moxart-apb-clock"
> +- #clock-cells : Should be 0
> +- reg : Should contain registers location and length
> +- clocks : Should contain phandle + clock-specifier for the parent clock
> +
> +Optional properties:
> +- clock-output-names : Should contain clock name
> +
> +
> +For example:
> +
> +       clk_pll: clk_pll@98100000 {
> +               compatible = "moxa,moxart-pll-clock";
> +               #clock-cells = <0>;
> +               reg = <0x98100000 0x34>;
> +       };
> +
> +       clk_apb: clk_apb@98100000 {
> +               compatible = "moxa,moxart-apb-clock";
> +               #clock-cells = <0>;
> +               reg = <0x98100000 0x34>;
> +               clocks = <&clk_pll>;
> +       };
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 0faf730..7940d0c 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-$(CONFIG_ARCH_EFM32)       += clk-efm32gg.o
> +obj-$(CONFIG_ARCH_MOXART)      += clk-moxart.o
>  obj-$(CONFIG_ARCH_NOMADIK)     += clk-nomadik.o
>  obj-$(CONFIG_ARCH_HIGHBANK)    += clk-highbank.o
>  obj-$(CONFIG_ARCH_HI3xxx)      += hisilicon/
> diff --git a/drivers/clk/clk-moxart.c b/drivers/clk/clk-moxart.c
> new file mode 100644
> index 0000000..30a3b69
> --- /dev/null
> +++ b/drivers/clk/clk-moxart.c
> @@ -0,0 +1,97 @@
> +/*
> + * MOXA ART SoCs clock driver.
> + *
> + * Copyright (C) 2013 Jonas Jensen
> + *
> + * Jonas Jensen <jonas.jensen@gmail.com>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2.  This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/io.h>
> +#include <linux/of_address.h>
> +#include <linux/clkdev.h>
> +
> +void __init moxart_of_pll_clk_init(struct device_node *node)
> +{
> +       static void __iomem *base;
> +       struct clk *clk, *ref_clk;
> +       unsigned int mul;
> +       const char *name = node->name;
> +       const char *parent_name;
> +
> +       of_property_read_string(node, "clock-output-names", &name);
> +       parent_name = of_clk_get_parent_name(node, 0);
> +
> +       base = of_iomap(node, 0);
> +       if (!base) {
> +               pr_err("%s: of_iomap failed\n", node->full_name);
> +               return;
> +       }
> +
> +       mul = readl(base + 0x30) >> 3 & 0x3f;
> +       iounmap(base);
> +
> +       ref_clk = of_clk_get(node, 0);
> +       if (IS_ERR(ref_clk)) {
> +               pr_err("%s: of_clk_get failed\n", node->full_name);
> +               return;
> +       }
> +
> +       clk = clk_register_fixed_factor(NULL, name, parent_name, 0, mul, 1);
> +       if (IS_ERR(clk)) {
> +               pr_err("%s: failed to register clock\n", node->full_name);
> +               return;
> +       }
> +
> +       clk_register_clkdev(clk, NULL, name);
> +       of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +CLK_OF_DECLARE(moxart_pll_clock, "moxa,moxart-pll-clock",
> +              moxart_of_pll_clk_init);
> +
> +void __init moxart_of_apb_clk_init(struct device_node *node)
> +{
> +       static void __iomem *base;
> +       struct clk *clk, *pll_clk;
> +       unsigned int div, val;
> +       unsigned int div_idx[] = { 2, 3, 4, 6, 8};
> +       const char *name = node->name;
> +       const char *parent_name;
> +
> +       of_property_read_string(node, "clock-output-names", &name);
> +       parent_name = of_clk_get_parent_name(node, 0);
> +
> +       base = of_iomap(node, 0);
> +       if (!base) {
> +               pr_err("%s: of_iomap failed\n", node->full_name);
> +               return;
> +       }
> +
> +       val = readl(base + 0xc) >> 4 & 0x7;
> +       iounmap(base);
> +
> +       if (val > 4)
> +               val = 0;
> +       div = div_idx[val] * 2;
> +
> +       pll_clk = of_clk_get(node, 0);
> +       if (IS_ERR(pll_clk)) {
> +               pr_err("%s: of_clk_get failed\n", node->full_name);
> +               return;
> +       }
> +
> +       clk = clk_register_fixed_factor(NULL, name, parent_name, 0, 1, div);
> +       if (IS_ERR(clk)) {
> +               pr_err("%s: failed to register clock\n", node->full_name);
> +               return;
> +       }
> +
> +       clk_register_clkdev(clk, NULL, name);
> +       of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +}
> +CLK_OF_DECLARE(moxart_apb_clock, "moxa,moxart-apb-clock",
> +              moxart_of_apb_clk_init);
> -- 
> 1.8.2.1
>