/* * Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com * * Authors: * Jyri Sarha <jsarha@ti.com> * Sergej Sawazki <ce3a@gmx.de> * * 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 implementation */ #include <linux/clk-provider.h> #include <linux/export.h> #include <linux/slab.h> #include <linux/gpio/consumer.h> #include <linux/err.h> #include <linux/device.h> #include <linux/platform_device.h> #include <linux/of_device.h> /** * DOC: basic gpio gated clock which can be enabled and disabled * with gpio output * Traits of this clock: * prepare - clk_(un)prepare only ensures parent is (un)prepared * enable - clk_enable and clk_disable are functional & control gpio * rate - inherits rate from parent. No clk_set_rate support * parent - fixed parent. No clk_set_parent support */ static int clk_gpio_gate_enable(struct clk_hw *hw) { struct clk_gpio *clk = to_clk_gpio(hw); gpiod_set_value(clk->gpiod, 1); return 0; } static void clk_gpio_gate_disable(struct clk_hw *hw) { struct clk_gpio *clk = to_clk_gpio(hw); gpiod_set_value(clk->gpiod, 0); } static int clk_gpio_gate_is_enabled(struct clk_hw *hw) { struct clk_gpio *clk = to_clk_gpio(hw); return gpiod_get_value(clk->gpiod); } const struct clk_ops clk_gpio_gate_ops = { .enable = clk_gpio_gate_enable, .disable = clk_gpio_gate_disable, .is_enabled = clk_gpio_gate_is_enabled, }; EXPORT_SYMBOL_GPL(clk_gpio_gate_ops); /** * 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 * rate - rate is only affected by parent switching. No clk_set_rate support * parent - parent is adjustable through clk_set_parent */ static u8 clk_gpio_mux_get_parent(struct clk_hw *hw) { struct clk_gpio *clk = to_clk_gpio(hw); return gpiod_get_value(clk->gpiod); } static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index) { struct clk_gpio *clk = to_clk_gpio(hw); gpiod_set_value(clk->gpiod, index); return 0; } const struct clk_ops clk_gpio_mux_ops = { .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); static struct clk_hw *clk_register_gpio(struct device *dev, const char *name, const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod, unsigned long flags, const struct clk_ops *clk_gpio_ops) { struct clk_gpio *clk_gpio; struct clk_hw *hw; struct clk_init_data init = {}; int err; if (dev) clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio), GFP_KERNEL); else clk_gpio = kzalloc(sizeof(*clk_gpio), GFP_KERNEL); if (!clk_gpio) return ERR_PTR(-ENOMEM); init.name = name; init.ops = clk_gpio_ops; init.flags = flags | CLK_IS_BASIC; init.parent_names = parent_names; init.num_parents = num_parents; clk_gpio->gpiod = gpiod; clk_gpio->hw.init = &init; hw = &clk_gpio->hw; if (dev) err = devm_clk_hw_register(dev, hw); else err = clk_hw_register(NULL, hw); if (!err) return hw; if (!dev) { kfree(clk_gpio); } return ERR_PTR(err); } /** * clk_hw_register_gpio_gate - register a gpio clock gate with the clock * framework * @dev: device that is registering this clock * @name: name of this clock * @parent_name: name of this clock's parent * @gpiod: gpio descriptor to gate this clock * @flags: clock flags */ struct clk_hw *clk_hw_register_gpio_gate(struct device *dev, const char *name, const char *parent_name, struct gpio_desc *gpiod, unsigned long flags) { return clk_register_gpio(dev, name, (parent_name ? &parent_name : NULL), (parent_name ? 1 : 0), gpiod, flags, &clk_gpio_gate_ops); } EXPORT_SYMBOL_GPL(clk_hw_register_gpio_gate); struct clk *clk_register_gpio_gate(struct device *dev, const char *name, const char *parent_name, struct gpio_desc *gpiod, unsigned long flags) { struct clk_hw *hw; hw = clk_hw_register_gpio_gate(dev, name, parent_name, gpiod, flags); if (IS_ERR(hw)) return ERR_CAST(hw); return hw->clk; } EXPORT_SYMBOL_GPL(clk_register_gpio_gate); /** * clk_hw_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: gpio descriptor to gate this clock * @flags: clock flags */ struct clk_hw *clk_hw_register_gpio_mux(struct device *dev, const char *name, const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod, unsigned long flags) { if (num_parents != 2) { pr_err("mux-clock %s must have 2 parents\n", name); return ERR_PTR(-EINVAL); } return clk_register_gpio(dev, name, parent_names, num_parents, gpiod, flags, &clk_gpio_mux_ops); } EXPORT_SYMBOL_GPL(clk_hw_register_gpio_mux); struct clk *clk_register_gpio_mux(struct device *dev, const char *name, const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod, unsigned long flags) { struct clk_hw *hw; hw = clk_hw_register_gpio_mux(dev, name, parent_names, num_parents, gpiod, flags); if (IS_ERR(hw)) return ERR_CAST(hw); return hw->clk; } EXPORT_SYMBOL_GPL(clk_register_gpio_mux); static int gpio_clk_driver_probe(struct platform_device *pdev) { struct device_node *node = pdev->dev.of_node; const char **parent_names, *gpio_name; unsigned int num_parents; struct gpio_desc *gpiod; struct clk *clk; bool is_mux; int ret; num_parents = of_clk_get_parent_count(node); if (num_parents) { parent_names = devm_kcalloc(&pdev->dev, num_parents, sizeof(char *), GFP_KERNEL); if (!parent_names) return -ENOMEM; of_clk_parent_fill(node, parent_names, num_parents); } else { parent_names = NULL; } is_mux = of_device_is_compatible(node, "gpio-mux-clock"); gpio_name = is_mux ? "select" : "enable"; gpiod = devm_gpiod_get(&pdev->dev, gpio_name, GPIOD_OUT_LOW); if (IS_ERR(gpiod)) { ret = PTR_ERR(gpiod); if (ret == -EPROBE_DEFER) pr_debug("%s: %s: GPIOs not yet available, retry later\n", node->name, __func__); else pr_err("%s: %s: Can't get '%s' named GPIO property\n", node->name, __func__, gpio_name); return ret; } if (is_mux) clk = clk_register_gpio_mux(&pdev->dev, node->name, parent_names, num_parents, gpiod, 0); else clk = clk_register_gpio_gate(&pdev->dev, node->name, parent_names ? parent_names[0] : NULL, gpiod, 0); if (IS_ERR(clk)) return PTR_ERR(clk); return of_clk_add_provider(node, of_clk_src_simple_get, clk); } static const struct of_device_id gpio_clk_match_table[] = { { .compatible = "gpio-mux-clock" }, { .compatible = "gpio-gate-clock" }, { } }; static struct platform_driver gpio_clk_driver = { .probe = gpio_clk_driver_probe, .driver = { .name = "gpio-clk", .of_match_table = gpio_clk_match_table, }, }; builtin_platform_driver(gpio_clk_driver);