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Diffstat (limited to '')
-rw-r--r-- | drivers/clk/clkdev.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c new file mode 100644 index 000000000..ee37d0be6 --- /dev/null +++ b/drivers/clk/clkdev.c @@ -0,0 +1,381 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/clk/clkdev.c + * + * Copyright (C) 2008 Russell King. + * + * Helper for the clk API to assist looking up a struct clk. + */ +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/device.h> +#include <linux/list.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/string.h> +#include <linux/mutex.h> +#include <linux/clk.h> +#include <linux/clkdev.h> +#include <linux/clk-provider.h> +#include <linux/of.h> + +#include "clk.h" + +static LIST_HEAD(clocks); +static DEFINE_MUTEX(clocks_mutex); + +/* + * Find the correct struct clk for the device and connection ID. + * We do slightly fuzzy matching here: + * An entry with a NULL ID is assumed to be a wildcard. + * If an entry has a device ID, it must match + * If an entry has a connection ID, it must match + * Then we take the most specific entry - with the following + * order of precedence: dev+con > dev only > con only. + */ +static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) +{ + struct clk_lookup *p, *cl = NULL; + int match, best_found = 0, best_possible = 0; + + if (dev_id) + best_possible += 2; + if (con_id) + best_possible += 1; + + lockdep_assert_held(&clocks_mutex); + + list_for_each_entry(p, &clocks, node) { + match = 0; + if (p->dev_id) { + if (!dev_id || strcmp(p->dev_id, dev_id)) + continue; + match += 2; + } + if (p->con_id) { + if (!con_id || strcmp(p->con_id, con_id)) + continue; + match += 1; + } + + if (match > best_found) { + cl = p; + if (match != best_possible) + best_found = match; + else + break; + } + } + return cl; +} + +struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id) +{ + struct clk_lookup *cl; + struct clk_hw *hw = ERR_PTR(-ENOENT); + + mutex_lock(&clocks_mutex); + cl = clk_find(dev_id, con_id); + if (cl) + hw = cl->clk_hw; + mutex_unlock(&clocks_mutex); + + return hw; +} + +static struct clk *__clk_get_sys(struct device *dev, const char *dev_id, + const char *con_id) +{ + struct clk_hw *hw = clk_find_hw(dev_id, con_id); + + return clk_hw_create_clk(dev, hw, dev_id, con_id); +} + +struct clk *clk_get_sys(const char *dev_id, const char *con_id) +{ + return __clk_get_sys(NULL, dev_id, con_id); +} +EXPORT_SYMBOL(clk_get_sys); + +struct clk *clk_get(struct device *dev, const char *con_id) +{ + const char *dev_id = dev ? dev_name(dev) : NULL; + struct clk_hw *hw; + + if (dev && dev->of_node) { + hw = of_clk_get_hw(dev->of_node, 0, con_id); + if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER) + return clk_hw_create_clk(dev, hw, dev_id, con_id); + } + + return __clk_get_sys(dev, dev_id, con_id); +} +EXPORT_SYMBOL(clk_get); + +void clk_put(struct clk *clk) +{ + __clk_put(clk); +} +EXPORT_SYMBOL(clk_put); + +static void __clkdev_add(struct clk_lookup *cl) +{ + mutex_lock(&clocks_mutex); + list_add_tail(&cl->node, &clocks); + mutex_unlock(&clocks_mutex); +} + +void clkdev_add(struct clk_lookup *cl) +{ + if (!cl->clk_hw) + cl->clk_hw = __clk_get_hw(cl->clk); + __clkdev_add(cl); +} +EXPORT_SYMBOL(clkdev_add); + +void clkdev_add_table(struct clk_lookup *cl, size_t num) +{ + mutex_lock(&clocks_mutex); + while (num--) { + cl->clk_hw = __clk_get_hw(cl->clk); + list_add_tail(&cl->node, &clocks); + cl++; + } + mutex_unlock(&clocks_mutex); +} + +#define MAX_DEV_ID 20 +#define MAX_CON_ID 16 + +struct clk_lookup_alloc { + struct clk_lookup cl; + char dev_id[MAX_DEV_ID]; + char con_id[MAX_CON_ID]; +}; + +static struct clk_lookup * __ref +vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, + va_list ap) +{ + struct clk_lookup_alloc *cla; + + cla = kzalloc(sizeof(*cla), GFP_KERNEL); + if (!cla) + return NULL; + + cla->cl.clk_hw = hw; + if (con_id) { + strscpy(cla->con_id, con_id, sizeof(cla->con_id)); + cla->cl.con_id = cla->con_id; + } + + if (dev_fmt) { + vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); + cla->cl.dev_id = cla->dev_id; + } + + return &cla->cl; +} + +static struct clk_lookup * +vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt, + va_list ap) +{ + struct clk_lookup *cl; + + cl = vclkdev_alloc(hw, con_id, dev_fmt, ap); + if (cl) + __clkdev_add(cl); + + return cl; +} + +/** + * clkdev_create - allocate and add a clkdev lookup structure + * @clk: struct clk to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_fmt: format string describing device name + * + * Returns a clk_lookup structure, which can be later unregistered and + * freed. + */ +struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id, + const char *dev_fmt, ...) +{ + struct clk_lookup *cl; + va_list ap; + + va_start(ap, dev_fmt); + cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap); + va_end(ap); + + return cl; +} +EXPORT_SYMBOL_GPL(clkdev_create); + +/** + * clkdev_hw_create - allocate and add a clkdev lookup structure + * @hw: struct clk_hw to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_fmt: format string describing device name + * + * Returns a clk_lookup structure, which can be later unregistered and + * freed. + */ +struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id, + const char *dev_fmt, ...) +{ + struct clk_lookup *cl; + va_list ap; + + va_start(ap, dev_fmt); + cl = vclkdev_create(hw, con_id, dev_fmt, ap); + va_end(ap); + + return cl; +} +EXPORT_SYMBOL_GPL(clkdev_hw_create); + +int clk_add_alias(const char *alias, const char *alias_dev_name, + const char *con_id, struct device *dev) +{ + struct clk *r = clk_get(dev, con_id); + struct clk_lookup *l; + + if (IS_ERR(r)) + return PTR_ERR(r); + + l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL, + alias_dev_name); + clk_put(r); + + return l ? 0 : -ENODEV; +} +EXPORT_SYMBOL(clk_add_alias); + +/* + * clkdev_drop - remove a clock dynamically allocated + */ +void clkdev_drop(struct clk_lookup *cl) +{ + mutex_lock(&clocks_mutex); + list_del(&cl->node); + mutex_unlock(&clocks_mutex); + kfree(cl); +} +EXPORT_SYMBOL(clkdev_drop); + +static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw, + const char *con_id, + const char *dev_id, ...) +{ + struct clk_lookup *cl; + va_list ap; + + va_start(ap, dev_id); + cl = vclkdev_create(hw, con_id, dev_id, ap); + va_end(ap); + + return cl; +} + +static int do_clk_register_clkdev(struct clk_hw *hw, + struct clk_lookup **cl, const char *con_id, const char *dev_id) +{ + if (IS_ERR(hw)) + return PTR_ERR(hw); + /* + * Since dev_id can be NULL, and NULL is handled specially, we must + * pass it as either a NULL format string, or with "%s". + */ + if (dev_id) + *cl = __clk_register_clkdev(hw, con_id, "%s", dev_id); + else + *cl = __clk_register_clkdev(hw, con_id, NULL); + + return *cl ? 0 : -ENOMEM; +} + +/** + * clk_register_clkdev - register one clock lookup for a struct clk + * @clk: struct clk to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_id: string describing device name + * + * con_id or dev_id may be NULL as a wildcard, just as in the rest of + * clkdev. + * + * To make things easier for mass registration, we detect error clks + * from a previous clk_register() call, and return the error code for + * those. This is to permit this function to be called immediately + * after clk_register(). + */ +int clk_register_clkdev(struct clk *clk, const char *con_id, + const char *dev_id) +{ + struct clk_lookup *cl; + + if (IS_ERR(clk)) + return PTR_ERR(clk); + + return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id, + dev_id); +} +EXPORT_SYMBOL(clk_register_clkdev); + +/** + * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw + * @hw: struct clk_hw to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_id: format string describing device name + * + * con_id or dev_id may be NULL as a wildcard, just as in the rest of + * clkdev. + * + * To make things easier for mass registration, we detect error clk_hws + * from a previous clk_hw_register_*() call, and return the error code for + * those. This is to permit this function to be called immediately + * after clk_hw_register_*(). + */ +int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id, + const char *dev_id) +{ + struct clk_lookup *cl; + + return do_clk_register_clkdev(hw, &cl, con_id, dev_id); +} +EXPORT_SYMBOL(clk_hw_register_clkdev); + +static void devm_clkdev_release(void *res) +{ + clkdev_drop(res); +} + +/** + * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw + * @dev: device this lookup is bound + * @hw: struct clk_hw to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_id: format string describing device name + * + * con_id or dev_id may be NULL as a wildcard, just as in the rest of + * clkdev. + * + * To make things easier for mass registration, we detect error clk_hws + * from a previous clk_hw_register_*() call, and return the error code for + * those. This is to permit this function to be called immediately + * after clk_hw_register_*(). + */ +int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw, + const char *con_id, const char *dev_id) +{ + struct clk_lookup *cl; + int rval; + + rval = do_clk_register_clkdev(hw, &cl, con_id, dev_id); + if (rval) + return rval; + + return devm_add_action_or_reset(dev, devm_clkdev_release, cl); +} +EXPORT_SYMBOL(devm_clk_hw_register_clkdev); |