[RFC PATCHv4 3/6] clk: TI-Nspire clock drivers
Daniel Tang
dt.tangr at gmail.com
Sat May 25 07:08:04 EDT 2013
Add support for TI-Nspire clocks.
Signed-off-by: Daniel Tang <dt.tangr at gmail.com>
---
.../devicetree/bindings/clock/nspire-clock.txt | 24 ++++
drivers/clk/Makefile | 1 +
drivers/clk/clk-nspire.c | 155 +++++++++++++++++++++
3 files changed, 180 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/nspire-clock.txt
create mode 100644 drivers/clk/clk-nspire.c
diff --git a/Documentation/devicetree/bindings/clock/nspire-clock.txt b/Documentation/devicetree/bindings/clock/nspire-clock.txt
new file mode 100644
index 0000000..7c3bc8b
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/nspire-clock.txt
@@ -0,0 +1,24 @@
+TI-NSPIRE Clocks
+
+Required properties:
+- compatible: Valid compatible properties include:
+ "lsi,nspire-cx-ahb-divider" for the AHB divider in the CX model
+ "lsi,nspire-classic-ahb-divider" for the AHB divider in the older model
+ "lsi,nspire-cx-clock" for the base clock in the CX model
+ "lsi,nspire-classic-clock" for the base clock in the older model
+
+- reg: Physical base address of the controller and length of memory mapped
+ region.
+
+Optional:
+- clocks: For the "nspire-*-ahb-divider" compatible clocks, this is the parent
+ clock where it divides the rate from.
+
+Example:
+
+ahb_clk {
+ #clock-cells = <0>;
+ compatible = "lsi,nspire-cx-clock";
+ reg = <0x900B0000 0x4>;
+ clocks = <&base_clk>;
+};
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 137d3e7..72ebbe1 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-composite.o
obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o
obj-$(CONFIG_ARCH_NOMADIK) += clk-nomadik.o
obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
+obj-$(CONFIG_ARCH_NSPIRE) += clk-nspire.o
obj-$(CONFIG_ARCH_MXS) += mxs/
obj-$(CONFIG_ARCH_SOCFPGA) += socfpga/
obj-$(CONFIG_PLAT_SPEAR) += spear/
diff --git a/drivers/clk/clk-nspire.c b/drivers/clk/clk-nspire.c
new file mode 100644
index 0000000..2546f7d
--- /dev/null
+++ b/drivers/clk/clk-nspire.c
@@ -0,0 +1,155 @@
+/*
+ * linux/drivers/clk/clk-nspire.c
+ *
+ * Copyright (C) 2013 Daniel Tang <tangrs at tangrs.id.au>
+ *
+ * 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/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define MHZ (1000 * 1000)
+
+#define BASE_CPU_SHIFT 1
+#define BASE_CPU_MASK 0x7F
+
+#define CPU_AHB_SHIFT 12
+#define CPU_AHB_MASK 0x07
+
+#define FIXED_BASE_SHIFT 8
+#define FIXED_BASE_MASK 0x01
+
+#define CLASSIC_BASE_SHIFT 16
+#define CLASSIC_BASE_MASK 0x1F
+
+#define CX_BASE_SHIFT 15
+#define CX_BASE_MASK 0x3F
+
+#define CX_UNKNOWN_SHIFT 21
+#define CX_UNKNOWN_MASK 0x03
+
+struct nspire_clk_info {
+ u32 base_clock;
+ u16 base_cpu_ratio;
+ u16 base_ahb_ratio;
+};
+
+
+#define EXTRACT(var, prop) (((var)>>prop##_SHIFT) & prop##_MASK)
+static void nspire_clkinfo_cx(u32 val, struct nspire_clk_info *clk)
+{
+ if (EXTRACT(val, FIXED_BASE))
+ clk->base_clock = 48 * MHZ;
+ else
+ clk->base_clock = 6 * EXTRACT(val, CX_BASE) * MHZ;
+
+ clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * EXTRACT(val, CX_UNKNOWN);
+ clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
+}
+
+static void nspire_clkinfo_classic(u32 val, struct nspire_clk_info *clk)
+{
+ if (EXTRACT(val, FIXED_BASE))
+ clk->base_clock = 27 * MHZ;
+ else
+ clk->base_clock = (300 - 6 * EXTRACT(val, CLASSIC_BASE)) * MHZ;
+
+ clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * 2;
+ clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
+}
+#undef EXTRACT
+
+static void __init nspire_ahbdiv_setup(struct device_node *node,
+ void (*get_clkinfo)(u32, struct nspire_clk_info *))
+{
+ u32 val;
+ void __iomem *io;
+ struct clk *clk;
+ const char *clk_name = node->name;
+ const char *parent_name;
+ struct nspire_clk_info info;
+
+ io = of_iomap(node, 0);
+ if (!io)
+ return;
+ val = readl(io);
+ iounmap(io);
+
+ get_clkinfo(val, &info);
+
+ of_property_read_string(node, "clock-output-names", &clk_name);
+ parent_name = of_clk_get_parent_name(node, 0);
+
+ clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
+ 1, info.base_ahb_ratio);
+ if (!IS_ERR(clk))
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+}
+
+static void __init nspire_ahbdiv_setup_cx(struct device_node *node)
+{
+ nspire_ahbdiv_setup(node, nspire_clkinfo_cx);
+}
+
+static void __init nspire_ahbdiv_setup_classic(struct device_node *node)
+{
+ nspire_ahbdiv_setup(node, nspire_clkinfo_classic);
+}
+
+CLK_OF_DECLARE(nspire_ahbdiv_cx, "lsi,nspire-cx-ahb-divider",
+ nspire_ahbdiv_setup_cx);
+CLK_OF_DECLARE(nspire_ahbdiv_classic, "lsi,nspire-classic-ahb-divider",
+ nspire_ahbdiv_setup_classic);
+
+static void __init nspire_clk_setup(struct device_node *node,
+ void (*get_clkinfo)(u32, struct nspire_clk_info *))
+{
+ u32 val;
+ void __iomem *io;
+ struct clk *clk;
+ const char *clk_name = node->name;
+ struct nspire_clk_info info;
+
+ io = of_iomap(node, 0);
+ if (!io)
+ return;
+ val = readl(io);
+ iounmap(io);
+
+ get_clkinfo(val, &info);
+
+ of_property_read_string(node, "clock-output-names", &clk_name);
+
+ clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT,
+ info.base_clock);
+ if (!IS_ERR(clk))
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+ else
+ return;
+
+ pr_info("TI-NSPIRE Base: %uMHz CPU: %uMHz AHB: %uMHz\n",
+ info.base_clock / MHZ,
+ info.base_clock / info.base_cpu_ratio / MHZ,
+ info.base_clock / info.base_ahb_ratio / MHZ);
+}
+
+static void __init nspire_clk_setup_cx(struct device_node *node)
+{
+ nspire_clk_setup(node, nspire_clkinfo_cx);
+}
+
+static void __init nspire_clk_setup_classic(struct device_node *node)
+{
+ nspire_clk_setup(node, nspire_clkinfo_classic);
+}
+
+CLK_OF_DECLARE(nspire_clk_cx, "lsi,nspire-cx-clock", nspire_clk_setup_cx);
+CLK_OF_DECLARE(nspire_clk_classic, "lsi,nspire-classic-clock",
+ nspire_clk_setup_classic);
--
1.8.1.3
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