Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756840AbbEVJOE (ORCPT ); Fri, 22 May 2015 05:14:04 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:41924 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755655AbbEVJN5 (ORCPT ); Fri, 22 May 2015 05:13:57 -0400 Message-ID: <555EF34C.1090507@ti.com> Date: Fri, 22 May 2015 12:13:48 +0300 From: Jyri Sarha User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Sergej Sawazki , , CC: , Subject: Re: [PATCH RFC v1] clk: add gpio controlled clock multiplexer References: <1431596413-20917-1-git-send-email-ce3a@gmx.de> In-Reply-To: <1431596413-20917-1-git-send-email-ce3a@gmx.de> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 12947 Lines: 416 On 05/14/15 12:40, Sergej Sawazki wrote: > Add a common clock driver for basic gpio controlled clock multiplexers. > This driver can be used for devices like 5V41068A or 831721I from IDT > or for discrete multiplexer circuits. The 'select' pin selects one of > two parent clocks. The optional 'enable' pin can be used to enable or > disable the clock output. > > Signed-off-by: Sergej Sawazki > --- > .../devicetree/bindings/clock/gpio-mux-clock.txt | 23 ++ > drivers/clk/Makefile | 1 + > drivers/clk/clk-gpio-mux.c | 301 +++++++++++++++++++++ > include/linux/clk-provider.h | 26 ++ > 4 files changed, 351 insertions(+) > create mode 100644 Documentation/devicetree/bindings/clock/gpio-mux-clock.txt > create mode 100644 drivers/clk/clk-gpio-mux.c > > diff --git a/Documentation/devicetree/bindings/clock/gpio-mux-clock.txt b/Documentation/devicetree/bindings/clock/gpio-mux-clock.txt > new file mode 100644 > index 0000000..2198061 > --- /dev/null > +++ b/Documentation/devicetree/bindings/clock/gpio-mux-clock.txt > @@ -0,0 +1,23 @@ > +Binding for simple gpio clock multiplexer. > + > +This binding uses the common clock binding[1]. > + > +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt > + > +Required properties: > +- compatible : shall be "gpio-mux-clock". > +- clocks: list of two references to parent clocks. > +- #clock-cells : from common clock binding; shall be set to 0. > +- select-gpios : GPIO reference for selecting the parent clock. > + > +Optional properties: > +- enable-gpios : GPIO reference for enabling and disabling the clock. I guess in theory you should not need the enable functionality here. You could just stack gpio-mux-clock on top of gpio-gate-clock. Best regards, Jyri > + > +Example: > + clock { > + compatible = "gpio-mux-clock"; > + clocks = <&parentclk1>, <&parentclk2>; > + #clock-cells = <0>; > + select-gpios = <&gpio 1 GPIO_ACTIVE_HIGH>; > + enable-gpios = <&gpio 2 GPIO_ACTIVE_HIGH>; > + }; > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile > index d965b3f..532a9bd 100644 > --- a/drivers/clk/Makefile > +++ b/drivers/clk/Makefile > @@ -10,6 +10,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-mux.o > obj-$(CONFIG_COMMON_CLK) += clk-composite.o > obj-$(CONFIG_COMMON_CLK) += clk-fractional-divider.o > obj-$(CONFIG_COMMON_CLK) += clk-gpio-gate.o > +obj-$(CONFIG_COMMON_CLK) += clk-gpio-mux.o > ifeq ($(CONFIG_OF), y) > obj-$(CONFIG_COMMON_CLK) += clk-conf.o > endif > diff --git a/drivers/clk/clk-gpio-mux.c b/drivers/clk/clk-gpio-mux.c > new file mode 100644 > index 0000000..9e41e92 > --- /dev/null > +++ b/drivers/clk/clk-gpio-mux.c > @@ -0,0 +1,301 @@ > +/* > + * Author: Sergej Sawazki > + * Based on clk-gpio-gate.c by Jyri Sarha and ti/mux.c by Tero Kristo > + * > + * 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 > + * published by the Free Software Foundation. > + * > + * Gpio controlled clock multiplexer implementation > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/** > + * DOC: basic clock multiplexer which can be controlled with a gpio output > + * Traits of this clock: > + * prepare - clk_prepare only ensures that parents are prepared > + * enable - clk_enable and clk_disable are functional & control gpio > + * rate - rate is only affected by parent switching. No clk_set_rate support > + * parent - parent is adjustable through clk_set_parent > + */ > + > +#define to_clk_gpio_mux(_hw) container_of(_hw, struct clk_gpio_mux, hw) > + > +static int clk_gpio_mux_enable(struct clk_hw *hw) > +{ > + struct clk_gpio_mux *clk = to_clk_gpio_mux(hw); > + > + if (!clk->gpiod_ena) { > + pr_err("%s: %s: DT property 'enable-gpios' not defined\n", > + __func__, __clk_get_name(hw->clk)); > + return -ENOENT; > + } > + > + gpiod_set_value(clk->gpiod_ena, 1); > + > + return 0; > +} > + > +static void clk_gpio_mux_disable(struct clk_hw *hw) > +{ > + struct clk_gpio_mux *clk = to_clk_gpio_mux(hw); > + > + if (!clk->gpiod_ena) { > + pr_err("%s: %s: DT property 'enable-gpios' not defined\n", > + __func__, __clk_get_name(hw->clk)); > + return; > + } > + > + gpiod_set_value(clk->gpiod_ena, 0); > +} > + > +static int clk_gpio_mux_is_enabled(struct clk_hw *hw) > +{ > + struct clk_gpio_mux *clk = to_clk_gpio_mux(hw); > + > + if (!clk->gpiod_ena) { > + pr_err("%s: %s: DT property 'enable-gpios' not defined\n", > + __func__, __clk_get_name(hw->clk)); > + return -EINVAL; > + } > + > + return gpiod_get_value(clk->gpiod_ena); > +} > + > +static u8 clk_gpio_mux_get_parent(struct clk_hw *hw) > +{ > + struct clk_gpio_mux *clk = to_clk_gpio_mux(hw); > + > + return gpiod_get_value(clk->gpiod_sel); > +} > + > +static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index) > +{ > + struct clk_gpio_mux *clk = to_clk_gpio_mux(hw); > + > + if (index > 1) > + return -EINVAL; > + > + gpiod_set_value(clk->gpiod_sel, index); > + > + return 0; > +} > + > +const struct clk_ops clk_gpio_mux_ops = { > + .enable = clk_gpio_mux_enable, > + .disable = clk_gpio_mux_disable, > + .is_enabled = clk_gpio_mux_is_enabled, > + .get_parent = clk_gpio_mux_get_parent, > + .set_parent = clk_gpio_mux_set_parent, > + .determine_rate = __clk_mux_determine_rate, > +}; > +EXPORT_SYMBOL_GPL(clk_gpio_mux_ops); > + > +/** > + * clk_register_gpio_mux - register a gpio clock mux with the clock framework > + * @dev: device that is registering this clock > + * @name: name of this clock > + * @parent_names: names of this clock's parents > + * @num_parents: number of parents listed in @parent_names > + * @gpiod_sel: gpio descriptor to select the parent of this clock multiplexer > + * @gpiod_ena: gpio descriptor to enable the output of this clock multiplexer > + * @clk_flags: optional flags for basic clock > + */ > +struct clk *clk_register_gpio_mux(struct device *dev, const char *name, > + const char **parent_names, u8 num_parents, > + struct gpio_desc *gpiod_sel, struct gpio_desc *gpiod_ena, > + unsigned long clk_flags) > +{ > + struct clk_gpio_mux *clk_gpio_mux = NULL; > + struct clk *clk = ERR_PTR(-EINVAL); > + struct clk_init_data init = { NULL }; > + unsigned long gpio_sel_flags, gpio_ena_flags; > + int err; > + > + if (dev) > + clk_gpio_mux = devm_kzalloc(dev, sizeof(struct clk_gpio_mux), > + GFP_KERNEL); > + else > + clk_gpio_mux = kzalloc(sizeof(struct clk_gpio_mux), GFP_KERNEL); > + > + if (!clk_gpio_mux) > + return ERR_PTR(-ENOMEM); > + > + if (gpiod_is_active_low(gpiod_sel)) > + gpio_sel_flags = GPIOF_OUT_INIT_HIGH; > + else > + gpio_sel_flags = GPIOF_OUT_INIT_LOW; > + > + if (dev) > + err = devm_gpio_request_one(dev, desc_to_gpio(gpiod_sel), > + gpio_sel_flags, name); > + else > + err = gpio_request_one(desc_to_gpio(gpiod_sel), > + gpio_sel_flags, name); > + > + if (err) { > + pr_err("%s: %s: Error requesting gpio %u\n", > + __func__, name, desc_to_gpio(gpiod_sel)); > + return ERR_PTR(err); > + } > + clk_gpio_mux->gpiod_sel = gpiod_sel; > + > + if (gpiod_ena != NULL) { > + if (gpiod_is_active_low(gpiod_ena)) > + gpio_ena_flags = GPIOF_OUT_INIT_HIGH; > + else > + gpio_ena_flags = GPIOF_OUT_INIT_LOW; > + > + if (dev) > + err = devm_gpio_request_one(dev, > + desc_to_gpio(gpiod_ena), > + gpio_ena_flags, name); > + else > + err = gpio_request_one(desc_to_gpio(gpiod_ena), > + gpio_ena_flags, name); > + > + if (err) { > + pr_err("%s: %s: Error requesting gpio %u\n", > + __func__, name, > + desc_to_gpio(gpiod_ena)); > + return ERR_PTR(err); > + } > + clk_gpio_mux->gpiod_ena = gpiod_ena; > + } > + > + init.name = name; > + init.ops = &clk_gpio_mux_ops; > + init.flags = clk_flags | CLK_IS_BASIC; > + init.parent_names = parent_names; > + init.num_parents = num_parents; > + > + clk_gpio_mux->hw.init = &init; > + > + clk = clk_register(dev, &clk_gpio_mux->hw); > + > + if (!IS_ERR(clk)) > + return clk; > + > + if (!dev) { > + kfree(clk_gpio_mux); > + gpiod_put(gpiod_ena); > + gpiod_put(gpiod_sel); > + } > + > + return clk; > +} > +EXPORT_SYMBOL_GPL(clk_register_gpio_mux); > + > +#ifdef CONFIG_OF > +/** > + * The clk_register_gpio_mux has to be delayed, because the EPROBE_DEFER > + * can not be handled properly at of_clk_init() call time. > + */ > + > +struct clk_gpio_mux_delayed_register_data { > + struct device_node *node; > + struct mutex lock; > + struct clk *clk; > +}; > + > +static struct clk *of_clk_gpio_mux_delayed_register_get( > + struct of_phandle_args *clkspec, > + void *_data) > +{ > + struct clk_gpio_mux_delayed_register_data *data = _data; > + struct clk *clk = ERR_PTR(-EINVAL); > + const char *clk_name = data->node->name; > + int i, num_parents; > + const char **parent_names; > + struct gpio_desc *gpiod_sel, *gpiod_ena; > + int gpio; > + u32 flags = 0; > + > + mutex_lock(&data->lock); > + > + if (data->clk) { > + mutex_unlock(&data->lock); > + return data->clk; > + } > + > + gpio = of_get_named_gpio_flags(data->node, "select-gpios", 0, NULL); > + if (!gpio_is_valid(gpio)) > + goto err_gpio; > + gpiod_sel = gpio_to_desc(gpio); > + > + gpio = of_get_named_gpio_flags(data->node, "enable-gpios", 0, NULL); > + if (!gpio_is_valid(gpio)) { > + if (gpio != -ENOENT) > + goto err_gpio; > + else > + gpiod_ena = NULL; > + } else { > + gpiod_ena = gpio_to_desc(gpio); > + } > + > + num_parents = of_clk_get_parent_count(data->node); > + if (num_parents < 2) { > + pr_err("mux-clock %s must have 2 parents\n", data->node->name); > + return clk; > + } > + > + parent_names = kzalloc((sizeof(char *) * num_parents), GFP_KERNEL); > + if (!parent_names) { > + kfree(parent_names); > + return clk; > + } > + > + for (i = 0; i < num_parents; i++) > + parent_names[i] = of_clk_get_parent_name(data->node, i); > + > + clk = clk_register_gpio_mux(NULL, clk_name, parent_names, num_parents, > + gpiod_sel, gpiod_ena, flags); > + if (IS_ERR(clk)) { > + mutex_unlock(&data->lock); > + return clk; > + } > + > + data->clk = clk; > + mutex_unlock(&data->lock); > + > + return clk; > + > +err_gpio: > + mutex_unlock(&data->lock); > + if (gpio == -EPROBE_DEFER) > + pr_warn("%s: %s: GPIOs not yet available, retry later\n", > + __func__, clk_name); > + else > + pr_err("%s: %s: Can't get GPIOs\n", > + __func__, clk_name); > + return ERR_PTR(gpio); > +} > + > +/** > + * of_gpio_mux_clk_setup() - Setup function for gpio controlled clock mux > + */ > +void __init of_gpio_mux_clk_setup(struct device_node *node) > +{ > + struct clk_gpio_mux_delayed_register_data *data; > + > + data = kzalloc(sizeof(struct clk_gpio_mux_delayed_register_data), > + GFP_KERNEL); > + if (!data) > + return; > + > + data->node = node; > + mutex_init(&data->lock); > + > + of_clk_add_provider(node, of_clk_gpio_mux_delayed_register_get, data); > +} > +EXPORT_SYMBOL_GPL(of_gpio_mux_clk_setup); > +CLK_OF_DECLARE(gpio_mux_clk, "gpio-mux-clock", of_gpio_mux_clk_setup); > +#endif > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h > index 5378c2a..89c6c5b 100644 > --- a/include/linux/clk-provider.h > +++ b/include/linux/clk-provider.h > @@ -549,6 +549,32 @@ struct clk *clk_register_gpio_gate(struct device *dev, const char *name, > void of_gpio_clk_gate_setup(struct device_node *node); > > /** > + * struct clk_gpio_mux - gpio controlled clock multiplexer > + * > + * @hw: handle between common and hardware-specific interfaces > + * @gpiod_sel: gpio descriptor to select the parent of this clock multiplexer > + * @gpiod_ena: gpio descriptor to enable the output of this clock multiplexer > + * > + * Clock with a gpio control for selecting the parent clock. > + * Implements .enable, .disable, .is_enabled, .get_parent, .set_parent and > + * .determine_rate > + */ > + > +struct clk_gpio_mux { > + struct clk_hw hw; > + struct gpio_desc *gpiod_sel; > + struct gpio_desc *gpiod_ena; > +}; > + > +extern const struct clk_ops clk_gpio_mux_ops; > +struct clk *clk_register_gpio_mux(struct device *dev, const char *name, > + const char **parent_names, u8 num_parents, > + struct gpio_desc *gpiod_sel, struct gpio_desc *gpiod_ena, > + unsigned long clk_flags); > + > +void of_gpio_mux_clk_setup(struct device_node *node); > + > +/** > * clk_register - allocate a new clock, register it and return an opaque cookie > * @dev: device that is registering this clock > * @hw: link to hardware-specific clock data > -- 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/