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Diffstat (limited to 'include/clk-uclass.h')
| -rw-r--r-- | include/clk-uclass.h | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/include/clk-uclass.h b/include/clk-uclass.h new file mode 100644 index 00000000000..8c07e723cff --- /dev/null +++ b/include/clk-uclass.h @@ -0,0 +1,236 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (c) 2015 Google, Inc + * Written by Simon Glass <sjg@chromium.org> + * Copyright (c) 2016, NVIDIA CORPORATION. + */ + +#ifndef _CLK_UCLASS_H +#define _CLK_UCLASS_H + +/* See clk.h for background documentation. */ + +#include <clk.h> + +struct ofnode_phandle_args; + +/** + * struct clk_ops - The functions that a clock driver must implement. + * @of_xlate: Translate a client's device-tree (OF) clock specifier. + * @request: Request a translated clock. + * @round_rate: Adjust a rate to the exact rate a clock can provide. + * @get_rate: Get current clock rate. + * @set_rate: Set current clock rate. + * @set_parent: Set current clock parent + * @enable: Enable a clock. + * @disable: Disable a clock. + * @dump: Print clock information. + * + * The individual methods are described more fully below. + */ +struct clk_ops { + int (*of_xlate)(struct clk *clock, + struct ofnode_phandle_args *args); + int (*request)(struct clk *clock); + ulong (*round_rate)(struct clk *clk, ulong rate); + ulong (*get_rate)(struct clk *clk); + ulong (*set_rate)(struct clk *clk, ulong rate); + int (*set_parent)(struct clk *clk, struct clk *parent); + int (*enable)(struct clk *clk); + int (*disable)(struct clk *clk); +#if IS_ENABLED(CONFIG_CMD_CLK) + void (*dump)(struct udevice *dev); +#endif +}; + +#if 0 /* For documentation only */ +/** + * of_xlate() - Translate a client's device-tree (OF) clock specifier. + * @clock: The clock struct to hold the translation result. + * @args: The clock specifier values from device tree. + * + * The clock core calls this function as the first step in implementing + * a client's clk_get_by_*() call. + * + * If this function pointer is set to NULL, the clock core will use a + * default implementation, which assumes #clock-cells = <1>, and that + * the DT cell contains a simple integer clock ID. + * + * This function should be a simple translation of @args into @clock->id and + * (optionally) @clock->data. All other processing, allocation, or error + * checking should take place in request(). + * + * At present, the clock API solely supports device-tree. If this + * changes, other xxx_xlate() functions may be added to support those + * other mechanisms. + * + * Return: + * * 0 on success + * * -%EINVAL if @args does not have the correct format. For example, it could + * have too many/few arguments. + * * -%ENOENT if @args has the correct format but cannot be translated. This can + * happen if translation involves a table lookup and @args is not present. + */ +int of_xlate(struct clk *clock, struct ofnode_phandle_args *args); + +/** + * request() - Request a translated clock. + * @clock: The clock struct to request; this has been filled in by + * a previoux xxx_xlate() function call, or by the caller + * of clk_request(). + * + * The clock core calls this function as the second step in + * implementing a client's clk_get_by_*() call, following a successful + * xxx_xlate() call, or as the only step in implementing a client's + * clk_request() call. + * + * This is the right place to do bounds checking (rejecting invalid or + * unimplemented clocks), allocate resources, or perform other setup not done + * during driver probe(). Most clock drivers should allocate resources in their + * probe() function, but it is possible to lazily initialize something here. + * + * Return: + * * 0 on success + * * -%ENOENT, if there is no clock corresponding to @clock->id and + * @clock->data. + */ +int request(struct clk *clock); + +/** + * round_rate() - Adjust a rate to the exact rate a clock can provide. + * @clk: The clock to query. + * @rate: Desired clock rate in Hz. + * + * This function returns a new rate which can be provided to set_rate(). This + * new rate should be the closest rate to @rate which can be set without + * rounding. The following pseudo-code should hold:: + * + * for all rate in range(ULONG_MAX): + * rounded = round_rate(clk, rate) + * new_rate = set_rate(clk, rate) + * assert(IS_ERR_VALUE(new_rate) || new_rate == rounded) + * + * Return: + * * The rounded rate in Hz on success + * * A negative error value from another API (such as clk_get_rate()). This + * function must not return an error for any other reason. + */ +ulong round_rate(struct clk *clk, ulong rate); + +/** + * get_rate() - Get current clock rate. + * @clk: The clock to query. + * + * This returns the current rate of a clock. If the clock is disabled, it + * returns the rate at which the clock would run if it was enabled. The + * following pseudo-code should hold:: + * + * disable(clk) + * rate = get_rate(clk) + * enable(clk) + * assert(get_rate(clk) == rate) + * + * Return: + * * The rate of @clk + * * -%ENOSYS if this function is not implemented for @clk + * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing + * this check in request(). + * * Another negative error value (such as %EIO or %ECOMM) if the rate could + * not be determined due to a bus error. + */ +ulong get_rate(struct clk *clk); + +/** + * set_rate() - Set current clock rate. + * @clk: The clock to manipulate. + * @rate: New clock rate in Hz. + * + * Set the rate of @clk to @rate. The actual rate may be rounded. However, + * excessive rounding should be avoided. It is left to the driver author's + * discretion when this function should attempt to round and when it should + * return an error. For example, a dividing clock might use the following + * pseudo-logic when implemening this function:: + * + * divisor = parent_rate / rate + * if divisor < min || divisor > max: + * return -EINVAL + * + * If there is any concern about rounding, prefer to let consumers make the + * decision by calling round_rate(). + * + * Return: + * * The new rate on success + * * -%ENOSYS if this function is not implemented for @clk + * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing + * this check in request(). + * * -%EINVAL if @rate is not valid for @clk. + * * Another negative error value (such as %EIO or %ECOMM) if the rate could + * not be set due to a bus error. + */ +ulong set_rate(struct clk *clk, ulong rate); + +/** + * set_parent() - Set current clock parent + * @clk: The clock to manipulate. + * @parent: New clock parent. + * + * Set the current parent of @clk to @parent. The rate of the clock may be + * modified by this call. If @clk was enabled before this function, it should + * remain enabled after this function, although it may be temporarily disabled + * if necessary. + * + * Return: + * * 0 on success + * * -%ENOSYS if this function is not implemented for @clk + * * -%ENOENT if @clk->id or @parent->id is invalid. Prefer using an assert + * instead, and doing this check in request(). + * * -%EINVAL if @parent is not a valid parent for @clk. + * * Another negative error value (such as %EIO or %ECOMM) if the parent could + * not be set due to a bus error. + */ +int set_parent(struct clk *clk, struct clk *parent); + +/** + * enable() - Enable a clock. + * @clk: The clock to manipulate. + * + * Enable (un-gate) the clock. This function should not modify the rate of the + * clock (see get_rate() for details). + * + * Return: + * * 0 on success + * * -%ENOSYS if this function is not implemented for @clk + * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing + * this check in request(). + * * Another negative error value (such as %EIO or %ECOMM) if the clock could + * not be enabled due to a bus error. + */ +int enable(struct clk *clk); + +/** + * disable() - Disable a clock. + * @clk: The clock to manipulate. + * + * Disable (gate) the clock. This function should not modify the rate of the + * clock (see get_rate() for details). + * + * * 0 on success + * * -%ENOSYS if this function is not implemented for @clk + * * -%ENOENT if @clk->id is invalid. Prefer using an assert instead, and doing + * this check in request(). + * * Another negative error value (such as %EIO or %ECOMM) if the clock could + * not be disabled due to a bus error. + */ +int disable(struct clk *clk); + +/** + * dump() - Print clock information. + * @dev: The clock device to dump. + * + * If present, this function is called by "clk dump" command for each + * bound device. + */ +void dump(struct udevice *dev); +#endif + +#endif |