clk: boston: Add a driver for MIPS Boston board clocks

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@imgtec.com>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: linux-clk@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16483/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index 0b977a6..5513b85 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8509,6 +8509,7 @@ M:        Paul Burton <paul.burton@imgtec.com>
 L:     linux-mips@linux-mips.org
 S:     Maintained
 F:     Documentation/devicetree/bindings/clock/img,boston-clock.txt
+F:     drivers/clk/imgtec/clk-boston.c
 F:     include/dt-bindings/clock/boston-clock.h
 
 MIROSOUND PCM20 FM RADIO RECEIVER DRIVER

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 36cfea3..251a221 100644 (file)
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -219,6 +219,7 @@ config COMMON_CLK_VC5
 
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
+source "drivers/clk/imgtec/Kconfig"
 source "drivers/clk/mediatek/Kconfig"
 source "drivers/clk/meson/Kconfig"
 source "drivers/clk/mvebu/Kconfig"

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index c19983a..a4a7c5d 100644 (file)
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -59,6 +59,7 @@ obj-y                                 += bcm/
 obj-$(CONFIG_ARCH_BERLIN)              += berlin/
 obj-$(CONFIG_H8300)                    += h8300/
 obj-$(CONFIG_ARCH_HISI)                        += hisilicon/
+obj-y                                  += imgtec/
 obj-$(CONFIG_ARCH_MXC)                 += imx/
 obj-$(CONFIG_MACH_INGENIC)             += ingenic/
 obj-$(CONFIG_COMMON_CLK_KEYSTONE)      += keystone/

diff --git a/drivers/clk/imgtec/Kconfig b/drivers/clk/imgtec/Kconfig
new file mode 100644 (file)
index 0000000..f6dcb74
--- /dev/null
+++ b/drivers/clk/imgtec/Kconfig
@@ -0,0 +1,9 @@
+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 (file)
index 0000000..ac779b8
--- /dev/null
+++ b/drivers/clk/imgtec/Makefile
@@ -0,0 +1 @@
+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 (file)
index 0000000..f18f103
--- /dev/null
+++ b/drivers/clk/imgtec/clk-boston.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2016-2017 Imagination Technologies
+ * Author: Paul Burton <paul.burton@imgtec.com>
+ *
+ * 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.
+ */
+
+#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(sizeof(*onecell) +
+                         (BOSTON_CLK_COUNT * sizeof(struct clk_hw *)),
+                         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));
+               return;
+       }
+       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));
+               return;
+       }
+       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));
+               return;
+       }
+       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);
+}
+
+/*
+ * 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);