Re: [PATCH v4 2/4] clk: boston: Add a driver for MIPS Boston board clocks
From: Stephen Boyd <hidden>
Date: 2017-06-14 16:01:06
Also in:
linux-clk
On 06/02, Paul Burton wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/clk/imgtec/Kconfig b/drivers/clk/imgtec/Kconfig new file mode 100644 index 000000000000..c2ea745928e4 --- /dev/null +++ b/drivers/clk/imgtec/Kconfig@@ -0,0 +1,10 @@ +config COMMON_CLK_BOSTON + bool "Clock driver for MIPS Boston boards" + depends on MIPS || COMPILE_TEST + depends on OF
What's the OF build dependency?
quoted hunk ↗ jump to hunk
+ 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 000000000000..ac779b8c22f2 --- /dev/null +++ b/drivers/clk/imgtec/Makefile@@ -0,0 +1 @@ +obj-$(CONFIG_COMMON_CLK_BOSTON) += clk-boston.odiff --git a/drivers/clk/imgtec/clk-boston.c b/drivers/clk/imgtec/clk-boston.c new file mode 100644 index 000000000000..98bb0b764d15 --- /dev/null +++ b/drivers/clk/imgtec/clk-boston.c@@ -0,0 +1,101 @@ +/* + * 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. + */ + +#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 + +struct clk_boston_state { + struct clk *clks[BOSTON_CLK_COUNT]; + struct clk_onecell_data onecell_data; +}; + +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_boston_state *state; + struct regmap *regmap; + struct clk *clk; + 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); + + state = kzalloc(sizeof(*state), GFP_KERNEL); + if (!state) + return; + + clk = clk_register_fixed_rate(NULL, "input", NULL, 0, in_freq);
Please use the clk_hw_register_*() APIs instead so that this driver only deals in clk_hw pointers.
+ if (IS_ERR(clk)) {
+ pr_err("failed to register input clock: %ld\n", PTR_ERR(clk));
+ return;
+ }
+ state->clks[BOSTON_CLK_INPUT] = clk;
+
+ clk = clk_register_fixed_rate(NULL, "sys", "input", 0, sys_freq);
+ if (IS_ERR(clk)) {
+ pr_err("failed to register sys clock: %ld\n", PTR_ERR(clk));
+ return;
+ }
+ state->clks[BOSTON_CLK_SYS] = clk;
+
+ clk = clk_register_fixed_rate(NULL, "cpu", "input", 0, cpu_freq);
+ if (IS_ERR(clk)) {
+ pr_err("failed to register cpu clock: %ld\n", PTR_ERR(clk));
+ return;
+ }
+ state->clks[BOSTON_CLK_CPU] = clk;
+
+ state->onecell_data.clks = state->clks;
+ state->onecell_data.clk_num = BOSTON_CLK_COUNT;
+
+ err = of_clk_add_provider(np, of_clk_src_onecell_get,
+ &state->onecell_data);Same for here, of_clk_add_hw_provider()
+ if (err)
+ pr_err("failed to add DT provider: %d\n", err);
+}
+CLK_OF_DECLARE(clk_boston, "img,boston-clock", clk_boston_setup);Can this be a platform driver? The syscon mfd can populate child nodes and this could be a driver that binds to the clock child node. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project