Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755803Ab3FQC7t (ORCPT ); Sun, 16 Jun 2013 22:59:49 -0400 Received: from mail-pd0-f173.google.com ([209.85.192.173]:47819 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755723Ab3FQC7l (ORCPT ); Sun, 16 Jun 2013 22:59:41 -0400 From: Mike Turquette To: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, devicetree-discuss@lists.ozlabs.org, =?UTF-8?q?Heiko=20St=C3=BCbner?= , Matt Sealey , Stephen Boyd , Mike Turquette Subject: [PATCH v2 4/5] clk: dt: binding for basic divider clock Date: Sun, 16 Jun 2013 19:58:24 -0700 Message-Id: <1371437905-15567-5-git-send-email-mturquette@linaro.org> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1371437905-15567-1-git-send-email-mturquette@linaro.org> References: <1371437905-15567-1-git-send-email-mturquette@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7982 Lines: 246 Devicetree binding for the basic clock divider, plus the setup function to register the clock. Based on the existing fixed-clock binding. Signed-off-by: Mike Turquette --- Changes since v1: * mask is u32, shift is u8 * use bit mask instead of bitfield width * DT property names use dashes instead of underscores * DT property names are more verbose * added minimum/maximum divider values to binding * shift property is optional in binding and can be auto-generated from a full 32-bit mask .../devicetree/bindings/clock/divider-clock.txt | 87 +++++++++++++++++++++ drivers/clk/clk-divider.c | 90 +++++++++++++++++++++- include/linux/clk-provider.h | 2 + 3 files changed, 178 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/clock/divider-clock.txt diff --git a/Documentation/devicetree/bindings/clock/divider-clock.txt b/Documentation/devicetree/bindings/clock/divider-clock.txt new file mode 100644 index 0000000..96bea07 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/divider-clock.txt @@ -0,0 +1,87 @@ +Binding for simple divider clock. + +This binding uses the common clock binding[1]. It assumes a +register-mapped adjustable clock rate divider that does not gate and has +only one input clock or parent. By default the value programmed into +the register is one less than the actual divisor value. E.g: + +register value actual divisor value +0 1 +1 2 +2 3 + +This assumption may be modified by the following optional properties: + +index-starts-at-one - valid divisor values start at 1, not the default +of 0. E.g: +register value actual divisor value +1 1 +2 2 +3 3 + +index-power-of-two - valid divisor values are powers of two. E.g: +register value actual divisor value +0 1 +1 2 +2 4 + +index-allow-zero - same as index_one, but zero is divide-by-1. E.g: +register value actual divisor value +0 1 +1 1 +2 2 + +Additionally a table of valid dividers may be supplied like so: + + table = <4 0>, <8, 1>; + +where the first value in the pair is the divider and the second value is +the programmed register bitfield. + +The binding must also provide the register to control the divider and +the mask for the corresponding control bits. Optionally the number of +bits to shift that mask, if necessary. If the shift value is missing it +is the same as supplying a zero shift. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt + +Required properties: +- compatible : shall be "divider-clock". +- #clock-cells : from common clock binding; shall be set to 0. +- clocks : link to phandle of parent clock +- reg : base address for register controlling adjustable divider +- bit-mask : arbitrary bitmask for programming the adjustable divider + +Optional properties: +- clock-output-names : from common clock binding. +- table : array of integer pairs defining divisors & bitfield values +- bit-shift : number of bits to shift the bit-mask, defaults to + (ffs(mask) - 1) if not present +- minimum-divider : min divisor for dividing the input clock rate, only + needed if the first divisor is offset from the default value +- maximum-divider : max divisor for dividing the input clock rate, only + needed if the max divisor is less than (mask + 1). +- index-starts-at-one : valid divisor programming starts at 1, not zero +- index-power-of-two : valid divisor programming must be a power of two +- index-allow-zero : implies index-one, and programming zero results in + divide-by-one + +Examples: + clock_foo: clock_foo@4a008100 { + compatible = "divider-clock"; + #clock-cells = <0>; + clocks = <&clock_baz>; + reg = <0x4a008100 0x4> + mask = <0x3> + maximum-divider = <3> + }; + + clock_bar: clock_bar@4a008108 { + #clock-cells = <0>; + compatible = "divider-clock"; + clocks = <&clock_foo>; + reg = <0x4a008108 0x4>; + mask = <0x1>; + shift = <0>; + table = < 4 0 >, < 8 1 >; + }; diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index ac9cb7f..8c42c7f 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -1,7 +1,7 @@ /* * Copyright (C) 2011 Sascha Hauer, Pengutronix * Copyright (C) 2011 Richard Zhao, Linaro - * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd + * Copyright (C) 2011-2013 Mike Turquette, Linaro Ltd * * 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 @@ -17,6 +17,8 @@ #include #include #include +#include +#include /* * DOC: basic adjustable divider clock that cannot gate @@ -340,3 +342,89 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name, return _register_divider(dev, name, parent_name, flags, reg, shift, ((1 << width) - 1), clk_divider_flags, table, lock); } + +#ifdef CONFIG_OF +struct clk_div_table *of_clk_get_div_table(struct device_node *node) +{ + int i; + int table_size = 0; + struct clk_div_table *table; + u32 pair[2]; + + table_size = of_count_phandle_with_args(node, "table", "#clock-cells"); + + if (table_size < 1) + return NULL; + + table = kzalloc(sizeof(struct clk_div_table) * table_size, GFP_KERNEL); + if (!table) { + pr_err("%s: unable to allocate memory for %s table\n", __func__, node->name); + return NULL; + } + + for (i = 0; i < table_size; i++) { + if (!of_property_read_u32_array(node, "table", pair, ARRAY_SIZE(pair))) { + table[i].val = pair[0]; + table[i].div = pair[1]; + } + } + + return table; +} + +/** + * of_divider_clk_setup() - Setup function for simple div rate clock + */ +void of_divider_clk_setup(struct device_node *node) +{ + struct clk *clk; + const char *clk_name = node->name; + void __iomem *reg; + const char *parent_name; + u8 clk_divider_flags = 0; + u32 mask = 0; + u8 shift = 0; + struct clk_div_table *table; + + of_property_read_string(node, "clock-output-names", &clk_name); + + parent_name = of_clk_get_parent_name(node, 0); + + reg = of_iomap(node, 0); + + if (of_property_read_u32(node, "bit-mask", &mask)) { + pr_err("%s: missing bit-mask property for %s\n", __func__, node->name); + return; + } + + if (of_property_read_u8(node, "bit-shift", &shift)) { + shift = __ffs(mask); + pr_debug("%s: bit-shift property defaults to 0x%x for %s\n", + __func__, shift, node->name); + } + + if (of_property_read_bool(node, "index-starts-at-one")) + clk_divider_flags |= CLK_DIVIDER_ONE_BASED; + + if (of_property_read_bool(node, "index-power-of-two")) + clk_divider_flags |= CLK_DIVIDER_POWER_OF_TWO; + + if (of_property_read_bool(node, "index-allow-zero")) + clk_divider_flags |= CLK_DIVIDER_ALLOW_ZERO; + + table = of_clk_get_div_table(node); + if (IS_ERR(table)) + return; + + clk = _register_divider(NULL, clk_name, + parent_name, 0, + reg, shift, mask, + clk_divider_flags, table, + NULL); + + if (!IS_ERR(clk)) + of_clk_add_provider(node, of_clk_src_simple_get, clk); +} +EXPORT_SYMBOL_GPL(of_divider_clk_setup); +CLK_OF_DECLARE(divider_clk, "divider-clock", of_divider_clk_setup); +#endif diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 24a04b8..723ce69 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -293,6 +293,8 @@ struct clk *clk_register_divider_table(struct device *dev, const char *name, u8 clk_divider_flags, const struct clk_div_table *table, spinlock_t *lock); +void of_divider_clk_setup(struct device_node *node); + /** * struct clk_mux - multiplexer clock * -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/