[PATCH v10] clk: add MOXA ART SoCs clock driver
From: Jonas Jensen <hidden>
Date: 2014-01-21 12:45:08
Also in:
linux-arm-kernel, lkml
Subsystem:
arm/moxa art soc, common clk framework, open firmware and flattened device tree bindings, the rest · Maintainers:
Krzysztof Kozlowski, Michael Turquette, Stephen Boyd, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
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 <redacted>
---
Notes:
Thanks for the reply Sudeep, changes are in v10.
Changes since v9:
1. rebase drivers/clk/Makefile to next-20140121
2. remove unnecessary switch
3. use a more elaborate commit message
Applies to next-20140121
.../bindings/clock/moxa,moxart-clock.txt | 48 +++++++++++
drivers/clk/Makefile | 1 +
drivers/clk/clk-moxart.c | 99 ++++++++++++++++++++++
3 files changed, 148 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 58b2d72..24361bf 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..7021748
--- /dev/null
+++ b/drivers/clk/clk-moxart.c@@ -0,0 +1,99 @@ +/* + * MOXA ART SoCs clock driver. + * + * Copyright (C) 2013 Jonas Jensen + * + * Jonas Jensen <jonas.jensen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> + * + * 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; + unsigned int div_idx[] = { 2, 3, 4, 6, 8}; + 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); + + if (val > 4) + val = 0; + div = div_idx[val]; + + pll_clk = of_clk_get(node, 0); + if (IS_ERR(pll_clk)) { + pr_err("%s: of_clk_get failed\n", node->full_name); + return; + } + + rate = clk_get_rate(pll_clk) / (div * 2); + + 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_apb_clock, "moxa,moxart-apb-clock", + moxart_of_apb_clk_init);
--
1.8.2.1
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