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Subject[PATCH v10] clk: add MOXA ART SoCs clock driver
Date
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>
---

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@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 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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