Add a driver for the clocks provided by the MIPS Boston board from
Imagination Technologies. 2 clocks are provided - the system clock & the
CPU clock - and each is a simple fixed rate clock whose frequency can be
determined by reading a register provided by the board.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---
drivers/clk/Kconfig | 9 ++++
drivers/clk/Makefile | 1 +
drivers/clk/clk-boston.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 141 insertions(+)
create mode 100644 drivers/clk/clk-boston.c
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index e2d9bd7..2680343 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -208,6 +208,15 @@ config COMMON_CLK_OXNAS
---help---
Support for the OXNAS SoC Family clocks.
+config COMMON_CLK_BOSTON
+ bool "Clock driver for MIPS Boston boards"
+ 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.
+
source "drivers/clk/bcm/Kconfig"
source "drivers/clk/hisilicon/Kconfig"
source "drivers/clk/meson/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 3b6f9cf..3b78e515 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -20,6 +20,7 @@ endif
obj-$(CONFIG_MACH_ASM9260) += clk-asm9260.o
obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o
obj-$(CONFIG_ARCH_AXXIA) += clk-axm5516.o
+obj-$(CONFIG_COMMON_CLK_BOSTON) += clk-boston.o
obj-$(CONFIG_COMMON_CLK_CDCE706) += clk-cdce706.o
obj-$(CONFIG_COMMON_CLK_CDCE925) += clk-cdce925.o
obj-$(CONFIG_ARCH_CLPS711X) += clk-clps711x.o
diff --git a/drivers/clk/clk-boston.c b/drivers/clk/clk-boston.c
new file mode 100644
index 0000000..4fa3fad
--- /dev/null
+++ b/drivers/clk/clk-boston.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ * Author: Paul Burton <paul.burton@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#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_CLK_COUNT 2
+
+struct clk_boston {
+ struct clk_hw hw;
+ struct regmap *regmap;
+ unsigned int id;
+};
+
+struct clk_boston_state {
+ struct clk *clk[BOSTON_CLK_COUNT];
+ struct clk_boston clk_boston[BOSTON_CLK_COUNT];
+ struct clk_onecell_data onecell_data[BOSTON_CLK_COUNT];
+};
+
+static const char *clk_names[BOSTON_CLK_COUNT] = {
+ [BOSTON_CLK_SYS] = "sys",
+ [BOSTON_CLK_CPU] = "cpu",
+};
+
+#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)
+
+static struct clk_boston *to_clk_boston(struct clk_hw *hw)
+{
+ return container_of(hw, struct clk_boston, hw);
+}
+
+static uint32_t ext_field(uint32_t val, uint32_t mask)
+{
+ return (val & mask) >> (ffs(mask) - 1);
+}
+
+static unsigned long clk_boston_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_boston *state = to_clk_boston(hw);
+ uint32_t in_rate, mul, div;
+ uint mmcmdiv;
+ int err;
+
+ err = regmap_read(state->regmap, BOSTON_PLAT_MMCMDIV, &mmcmdiv);
+ if (err)
+ return 0;
+
+ in_rate = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_INPUT);
+ mul = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_MUL);
+
+ switch (state->id) {
+ case BOSTON_CLK_SYS:
+ div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK0DIV);
+ break;
+ case BOSTON_CLK_CPU:
+ div = ext_field(mmcmdiv, BOSTON_PLAT_MMCMDIV_CLK1DIV);
+ break;
+ default:
+ return 0;
+ }
+
+ return (in_rate * mul * 1000000) / div;
+}
+
+static const struct clk_ops clk_boston_ops = {
+ .recalc_rate = clk_boston_recalc_rate,
+};
+
+static void __init clk_boston_setup(struct device_node *np)
+{
+ struct clk_boston_state *state;
+ struct clk_init_data init;
+ struct regmap *regmap;
+ int i, err;
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return;
+
+ regmap = syscon_regmap_lookup_by_phandle(np, "regmap");
+ if (IS_ERR(regmap)) {
+ pr_err("failed to find regmap\n");
+ return;
+ }
+
+ for (i = 0; i < BOSTON_CLK_COUNT; i++) {
+ memset(&init, 0, sizeof(init));
+ init.flags = CLK_IS_BASIC;
+ init.name = clk_names[i];
+ init.ops = &clk_boston_ops;
+
+ state->clk_boston[i].hw.init = &init;
+ state->clk_boston[i].id = i;
+ state->clk_boston[i].regmap = regmap;
+
+ state->clk[i] = clk_register(NULL, &state->clk_boston[i].hw);
+ if (IS_ERR(state->clk[i])) {
+ pr_err("failed to register clock: %ld\n",
+ PTR_ERR(state->clk[i]));
+ return;
+ }
+ }
+
+ state->onecell_data->clks = state->clk;
+ state->onecell_data->clk_num = BOSTON_CLK_COUNT;
+
+ err = of_clk_add_provider(np, of_clk_src_onecell_get,
+ state->onecell_data);
+ if (err)
+ pr_err("failed to add DT provider: %d\n", err);
+}
+CLK_OF_DECLARE(clk_boston, "img,boston-clock", clk_boston_setup);
--
2.9.3
