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path: root/drivers/clk/imgtec
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-rw-r--r--drivers/clk/imgtec/Kconfig10
-rw-r--r--drivers/clk/imgtec/Makefile2
-rw-r--r--drivers/clk/imgtec/clk-boston.c111
3 files changed, 123 insertions, 0 deletions
diff --git a/drivers/clk/imgtec/Kconfig b/drivers/clk/imgtec/Kconfig
new file mode 100644
index 000000000..c965fd091
--- /dev/null
+++ b/drivers/clk/imgtec/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config COMMON_CLK_BOSTON
+ bool "Clock driver for MIPS Boston boards"
+ depends on MIPS || COMPILE_TEST
+ select MFD_SYSCON
+ help
+ Enable this to support the system & CPU clocks on the MIPS Boston
+ development board from Imagination Technologies. These are simple
+ fixed rate clocks whose rate is determined by reading a platform
+ provided register.
diff --git a/drivers/clk/imgtec/Makefile b/drivers/clk/imgtec/Makefile
new file mode 100644
index 000000000..d2e81426c
--- /dev/null
+++ b/drivers/clk/imgtec/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_COMMON_CLK_BOSTON) += clk-boston.o
diff --git a/drivers/clk/imgtec/clk-boston.c b/drivers/clk/imgtec/clk-boston.c
new file mode 100644
index 000000000..b00cbd045
--- /dev/null
+++ b/drivers/clk/imgtec/clk-boston.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016-2017 Imagination Technologies
+ * Author: Paul Burton <paul.burton@mips.com>
+ */
+
+#define pr_fmt(fmt) "clk-boston: " fmt
+
+#include <linux/clk-provider.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/mfd/syscon.h>
+
+#include <dt-bindings/clock/boston-clock.h>
+
+#define BOSTON_PLAT_MMCMDIV 0x30
+# define BOSTON_PLAT_MMCMDIV_CLK0DIV (0xff << 0)
+# define BOSTON_PLAT_MMCMDIV_INPUT (0xff << 8)
+# define BOSTON_PLAT_MMCMDIV_MUL (0xff << 16)
+# define BOSTON_PLAT_MMCMDIV_CLK1DIV (0xff << 24)
+
+#define BOSTON_CLK_COUNT 3
+
+static u32 ext_field(u32 val, u32 mask)
+{
+ return (val & mask) >> (ffs(mask) - 1);
+}
+
+static void __init clk_boston_setup(struct device_node *np)
+{
+ unsigned long in_freq, cpu_freq, sys_freq;
+ uint mmcmdiv, mul, cpu_div, sys_div;
+ struct clk_hw_onecell_data *onecell;
+ struct regmap *regmap;
+ struct clk_hw *hw;
+ int err;
+
+ regmap = syscon_node_to_regmap(np->parent);
+ if (IS_ERR(regmap)) {
+ pr_err("failed to find regmap\n");
+ return;
+ }
+
+ err = regmap_read(regmap, BOSTON_PLAT_MMCMDIV, &mmcmdiv);
+ if (err) {
+ pr_err("failed to read mmcm_div register: %d\n", err);
+ return;
+ }
+
+ in_freq = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_INPUT) * 1000000;
+ mul = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_MUL);
+
+ sys_div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK0DIV);
+ sys_freq = mult_frac(in_freq, mul, sys_div);
+
+ cpu_div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK1DIV);
+ cpu_freq = mult_frac(in_freq, mul, cpu_div);
+
+ onecell = kzalloc(struct_size(onecell, hws, BOSTON_CLK_COUNT),
+ GFP_KERNEL);
+ if (!onecell)
+ return;
+
+ onecell->num = BOSTON_CLK_COUNT;
+
+ hw = clk_hw_register_fixed_rate(NULL, "input", NULL, 0, in_freq);
+ if (IS_ERR(hw)) {
+ pr_err("failed to register input clock: %ld\n", PTR_ERR(hw));
+ goto fail_input;
+ }
+ onecell->hws[BOSTON_CLK_INPUT] = hw;
+
+ hw = clk_hw_register_fixed_rate(NULL, "sys", "input", 0, sys_freq);
+ if (IS_ERR(hw)) {
+ pr_err("failed to register sys clock: %ld\n", PTR_ERR(hw));
+ goto fail_sys;
+ }
+ onecell->hws[BOSTON_CLK_SYS] = hw;
+
+ hw = clk_hw_register_fixed_rate(NULL, "cpu", "input", 0, cpu_freq);
+ if (IS_ERR(hw)) {
+ pr_err("failed to register cpu clock: %ld\n", PTR_ERR(hw));
+ goto fail_cpu;
+ }
+ onecell->hws[BOSTON_CLK_CPU] = hw;
+
+ err = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, onecell);
+ if (err) {
+ pr_err("failed to add DT provider: %d\n", err);
+ goto fail_clk_add;
+ }
+
+ return;
+
+fail_clk_add:
+ clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_CPU]);
+fail_cpu:
+ clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_SYS]);
+fail_sys:
+ clk_hw_unregister_fixed_rate(onecell->hws[BOSTON_CLK_INPUT]);
+fail_input:
+ kfree(onecell);
+}
+
+/*
+ * Use CLK_OF_DECLARE so that this driver is probed early enough to provide the
+ * CPU frequency for use with the GIC or cop0 counters/timers.
+ */
+CLK_OF_DECLARE(clk_boston, "img,boston-clock", clk_boston_setup);