On 17/01/14 15:03, Jonas Jensen wrote:
> This patch adds MOXA ART SoCs clock driver support.
>
> Signed-off-by: Jonas Jensen <[email protected]>
> ---
>
> Notes:
> Changes since v8:
>
> 1. rebase drivers/clk/Makefile to next-20140117
>
> DT bindings document:
>
> 2. use two separate sections describing PLL/APB
> 3. update example
>
> Applies to next-20140117
>
> .../bindings/clock/moxa,moxart-clock.txt | 48 +++++++++
> drivers/clk/Makefile | 1 +
> drivers/clk/clk-moxart.c | 112
> +++++++++++++++++++++
> 3 files changed, 161 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..242e3fc
> --- /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 to 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 to 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 0c16e9c..ed5d58d 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..f0436a3
> --- /dev/null
> +++ b/drivers/clk/clk-moxart.c
> @@ -0,0 +1,112 @@
> +/*
> + * MOXA ART SoCs clock driver.
> + *
> + * Copyright (C) 2013 Jonas Jensen
> + *
> + * Jonas Jensen <[email protected]>
> + *
> + * 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 long rate;
> + unsigned int mul;
> + const char *name = node->name;
> +
> + of_property_read_string(node, "clock-output-names", &name);
> +
> + 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;
> + }
> +
> + rate = mul * clk_get_rate(ref_clk);
> +
> + clk = clk_register_fixed_rate(NULL, name, NULL, CLK_IS_ROOT, rate);
> + if (IS_ERR(clk)) {
> + pr_err("%s: clk_register_fixed_rate failed\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 long rate;
> + unsigned int div, val;
> + const char *name = node->name;
> +
> + of_property_read_string(node, "clock-output-names", &name);
> +
> + 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);
> +
> + switch (val) {
> + case 1:
> + div = 3;
> + break;
> + case 2:
> + div = 4;
> + break;
> + case 3:
> + div = 6;
> + break;
> + case 4:
> + div = 8;
> + break;
> + default:
> + div = 2;
> + break;
> + }
How about something like this to avoid unnecessary switch:
int div_idx[] = { 2, 3, 4, 6, 8};
if (val > 4)
val = 0;
div = div_idx[val];
Regards,
Sudeep
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