drivers/clk/clk-scmi.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * System Control and Power Interface (SCMI) Protocol based clock driver
  *
  * Copyright (C) 2018-2022 ARM Ltd.
  */

 #include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/of.h>
 #include <linux/module.h>
 #include <linux/scmi_protocol.h>
 #include <asm/div64.h>

 static const struct scmi_clk_proto_ops *scmi_proto_clk_ops;

 struct scmi_clk {
 	u32 id;
 	struct clk_hw hw;
 	const struct scmi_clock_info *info;
 	const struct scmi_protocol_handle *ph;
 };

 #define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw)

 static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
 					  unsigned long parent_rate)
 {
 	int ret;
 	u64 rate;
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	ret = scmi_proto_clk_ops->rate_get(clk->ph, clk->id, &rate);
 	if (ret)
 		return 0;
 	return rate;
 }

 static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 				unsigned long *parent_rate)
 {
 	u64 fmin, fmax, ftmp;
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	/*
 	 * We can't figure out what rate it will be, so just return the
 	 * rate back to the caller. scmi_clk_recalc_rate() will be called
 	 * after the rate is set and we'll know what rate the clock is
 	 * running at then.
 	 */
 	if (clk->info->rate_discrete)
 		return rate;

 	fmin = clk->info->range.min_rate;
 	fmax = clk->info->range.max_rate;
 	if (rate <= fmin)
 		return fmin;
 	else if (rate >= fmax)
 		return fmax;

 	ftmp = rate - fmin;
 	ftmp += clk->info->range.step_size - 1; /* to round up */
 	do_div(ftmp, clk->info->range.step_size);

 	return ftmp * clk->info->range.step_size + fmin;
 }

 static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 			     unsigned long parent_rate)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	return scmi_proto_clk_ops->rate_set(clk->ph, clk->id, rate);
 }

 static int scmi_clk_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	return scmi_proto_clk_ops->enable(clk->ph, clk->id);
 }

 static void scmi_clk_disable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	scmi_proto_clk_ops->disable(clk->ph, clk->id);
 }

 static int scmi_clk_atomic_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	return scmi_proto_clk_ops->enable_atomic(clk->ph, clk->id);
 }

 static void scmi_clk_atomic_disable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);

 	scmi_proto_clk_ops->disable_atomic(clk->ph, clk->id);
 }

 /*
  * We can provide enable/disable atomic callbacks only if the underlying SCMI
  * transport for an SCMI instance is configured to handle SCMI commands in an
  * atomic manner.
  *
  * When no SCMI atomic transport support is available we instead provide only
  * the prepare/unprepare API, as allowed by the clock framework when atomic
  * calls are not available.
  *
  * Two distinct sets of clk_ops are provided since we could have multiple SCMI
  * instances with different underlying transport quality, so they cannot be
  * shared.
  */
 static const struct clk_ops scmi_clk_ops = {
 	.recalc_rate = scmi_clk_recalc_rate,
 	.round_rate = scmi_clk_round_rate,
 	.set_rate = scmi_clk_set_rate,
 	.prepare = scmi_clk_enable,
 	.unprepare = scmi_clk_disable,
 };

 static const struct clk_ops scmi_atomic_clk_ops = {
 	.recalc_rate = scmi_clk_recalc_rate,
 	.round_rate = scmi_clk_round_rate,
 	.set_rate = scmi_clk_set_rate,
 	.enable = scmi_clk_atomic_enable,
 	.disable = scmi_clk_atomic_disable,
 };

 static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
 			     const struct clk_ops *scmi_ops)
 {
 	int ret;
 	unsigned long min_rate, max_rate;

 	struct clk_init_data init = {
 		.flags = CLK_GET_RATE_NOCACHE,
 		.num_parents = 0,
 		.ops = scmi_ops,
 		.name = sclk->info->name,
 	};

 	sclk->hw.init = &init;
 	ret = devm_clk_hw_register(dev, &sclk->hw);
 	if (ret)
 		return ret;

 	if (sclk->info->rate_discrete) {
 		int num_rates = sclk->info->list.num_rates;

 		if (num_rates <= 0)
 			return -EINVAL;

 		min_rate = sclk->info->list.rates[0];
 		max_rate = sclk->info->list.rates[num_rates - 1];
 	} else {
 		min_rate = sclk->info->range.min_rate;
 		max_rate = sclk->info->range.max_rate;
 	}

 	clk_hw_set_rate_range(&sclk->hw, min_rate, max_rate);
 	return ret;
 }

 static int scmi_clocks_probe(struct scmi_device *sdev)
 {
 	int idx, count, err;
 	unsigned int atomic_threshold;
 	bool is_atomic;
 	struct clk_hw **hws;
 	struct clk_hw_onecell_data *clk_data;
 	struct device *dev = &sdev->dev;
 	struct device_node *np = dev->of_node;
 	const struct scmi_handle *handle = sdev->handle;
 	struct scmi_protocol_handle *ph;

 	if (!handle)
 		return -ENODEV;

 	scmi_proto_clk_ops =
 		handle->devm_protocol_get(sdev, SCMI_PROTOCOL_CLOCK, &ph);
 	if (IS_ERR(scmi_proto_clk_ops))
 		return PTR_ERR(scmi_proto_clk_ops);

 	count = scmi_proto_clk_ops->count_get(ph);
 	if (count < 0) {
 		dev_err(dev, "%pOFn: invalid clock output count\n", np);
 		return -EINVAL;
 	}

 	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, count),
 				GFP_KERNEL);
 	if (!clk_data)
 		return -ENOMEM;

 	clk_data->num = count;
 	hws = clk_data->hws;

 	is_atomic = handle->is_transport_atomic(handle, &atomic_threshold);

 	for (idx = 0; idx < count; idx++) {
 		struct scmi_clk *sclk;
 		const struct clk_ops *scmi_ops;

 		sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
 		if (!sclk)
 			return -ENOMEM;

 		sclk->info = scmi_proto_clk_ops->info_get(ph, idx);
 		if (!sclk->info) {
 			dev_dbg(dev, "invalid clock info for idx %d\n", idx);
 			continue;
 		}

 		sclk->id = idx;
 		sclk->ph = ph;

 		/*
 		 * Note that when transport is atomic but SCMI protocol did not
 		 * specify (or support) an enable_latency associated with a
 		 * clock, we default to use atomic operations mode.
 		 */
 		if (is_atomic &&
 		    sclk->info->enable_latency <= atomic_threshold)
 			scmi_ops = &scmi_atomic_clk_ops;
 		else
 			scmi_ops = &scmi_clk_ops;

 		err = scmi_clk_ops_init(dev, sclk, scmi_ops);
 		if (err) {
 			dev_err(dev, "failed to register clock %d\n", idx);
 			devm_kfree(dev, sclk);
 			hws[idx] = NULL;
 		} else {
 			dev_dbg(dev, "Registered clock:%s%s\n",
 				sclk->info->name,
 				scmi_ops == &scmi_atomic_clk_ops ?
 				" (atomic ops)" : "");
 			hws[idx] = &sclk->hw;
 		}
 	}

 	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
 					   clk_data);
 }

 static const struct scmi_device_id scmi_id_table[] = {
 	{ SCMI_PROTOCOL_CLOCK, "clocks" },
 	{ },
 };
 MODULE_DEVICE_TABLE(scmi, scmi_id_table);

 static struct scmi_driver scmi_clocks_driver = {
 	.name = "scmi-clocks",
 	.probe = scmi_clocks_probe,
 	.id_table = scmi_id_table,
 };
 module_scmi_driver(scmi_clocks_driver);

 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 MODULE_DESCRIPTION("ARM SCMI clock driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* System Control and Power Interface (SCMI) Protocol based clock driver
	*
	* Copyright (C) 2018-2022 ARM Ltd.
	*/

	#include <linux/clk-provider.h>
	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/of.h>
	#include <linux/module.h>
	#include <linux/scmi_protocol.h>
	#include <asm/div64.h>

	static const struct scmi_clk_proto_ops *scmi_proto_clk_ops;

	struct scmi_clk {
	u32 id;
	struct clk_hw hw;
	const struct scmi_clock_info *info;
	const struct scmi_protocol_handle *ph;
	};

	#define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw)

	static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
	{
	int ret;
	u64 rate;
	struct scmi_clk *clk = to_scmi_clk(hw);

	ret = scmi_proto_clk_ops->rate_get(clk->ph, clk->id, &rate);
	if (ret)
	return 0;
	return rate;
	}

	static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *parent_rate)
	{
	u64 fmin, fmax, ftmp;
	struct scmi_clk *clk = to_scmi_clk(hw);

	/*
	* We can't figure out what rate it will be, so just return the
	* rate back to the caller. scmi_clk_recalc_rate() will be called
	* after the rate is set and we'll know what rate the clock is
	* running at then.
	*/
	if (clk->info->rate_discrete)
	return rate;

	fmin = clk->info->range.min_rate;
	fmax = clk->info->range.max_rate;
	if (rate <= fmin)
	return fmin;
	else if (rate >= fmax)
	return fmax;

	ftmp = rate - fmin;
	ftmp += clk->info->range.step_size - 1; /* to round up */
	do_div(ftmp, clk->info->range.step_size);

	return ftmp * clk->info->range.step_size + fmin;
	}

	static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
	{
	struct scmi_clk *clk = to_scmi_clk(hw);

	return scmi_proto_clk_ops->rate_set(clk->ph, clk->id, rate);
	}

	static int scmi_clk_enable(struct clk_hw *hw)
	{
	struct scmi_clk *clk = to_scmi_clk(hw);

	return scmi_proto_clk_ops->enable(clk->ph, clk->id);
	}

	static void scmi_clk_disable(struct clk_hw *hw)
	{
	struct scmi_clk *clk = to_scmi_clk(hw);

	scmi_proto_clk_ops->disable(clk->ph, clk->id);
	}

	static int scmi_clk_atomic_enable(struct clk_hw *hw)
	{
	struct scmi_clk *clk = to_scmi_clk(hw);

	return scmi_proto_clk_ops->enable_atomic(clk->ph, clk->id);
	}

	static void scmi_clk_atomic_disable(struct clk_hw *hw)
	{
	struct scmi_clk *clk = to_scmi_clk(hw);

	scmi_proto_clk_ops->disable_atomic(clk->ph, clk->id);
	}

	/*
	* We can provide enable/disable atomic callbacks only if the underlying SCMI
	* transport for an SCMI instance is configured to handle SCMI commands in an
	* atomic manner.
	*
	* When no SCMI atomic transport support is available we instead provide only
	* the prepare/unprepare API, as allowed by the clock framework when atomic
	* calls are not available.
	*
	* Two distinct sets of clk_ops are provided since we could have multiple SCMI
	* instances with different underlying transport quality, so they cannot be
	* shared.
	*/
	static const struct clk_ops scmi_clk_ops = {
	.recalc_rate = scmi_clk_recalc_rate,
	.round_rate = scmi_clk_round_rate,
	.set_rate = scmi_clk_set_rate,
	.prepare = scmi_clk_enable,
	.unprepare = scmi_clk_disable,
	};

	static const struct clk_ops scmi_atomic_clk_ops = {
	.recalc_rate = scmi_clk_recalc_rate,
	.round_rate = scmi_clk_round_rate,
	.set_rate = scmi_clk_set_rate,
	.enable = scmi_clk_atomic_enable,
	.disable = scmi_clk_atomic_disable,
	};

	static int scmi_clk_ops_init(struct device dev, struct scmi_clk sclk,
	const struct clk_ops *scmi_ops)
	{
	int ret;
	unsigned long min_rate, max_rate;

	struct clk_init_data init = {
	.flags = CLK_GET_RATE_NOCACHE,
	.num_parents = 0,
	.ops = scmi_ops,
	.name = sclk->info->name,
	};

	sclk->hw.init = &init;
	ret = devm_clk_hw_register(dev, &sclk->hw);
	if (ret)
	return ret;

	if (sclk->info->rate_discrete) {
	int num_rates = sclk->info->list.num_rates;

	if (num_rates <= 0)
	return -EINVAL;

	min_rate = sclk->info->list.rates[0];
	max_rate = sclk->info->list.rates[num_rates - 1];
	} else {
	min_rate = sclk->info->range.min_rate;
	max_rate = sclk->info->range.max_rate;
	}

	clk_hw_set_rate_range(&sclk->hw, min_rate, max_rate);
	return ret;
	}

	static int scmi_clocks_probe(struct scmi_device *sdev)
	{
	int idx, count, err;
	unsigned int atomic_threshold;
	bool is_atomic;
	struct clk_hw **hws;
	struct clk_hw_onecell_data *clk_data;
	struct device *dev = &sdev->dev;
	struct device_node *np = dev->of_node;
	const struct scmi_handle *handle = sdev->handle;
	struct scmi_protocol_handle *ph;

	if (!handle)
	return -ENODEV;

	scmi_proto_clk_ops =
	handle->devm_protocol_get(sdev, SCMI_PROTOCOL_CLOCK, &ph);
	if (IS_ERR(scmi_proto_clk_ops))
	return PTR_ERR(scmi_proto_clk_ops);

	count = scmi_proto_clk_ops->count_get(ph);
	if (count < 0) {
	dev_err(dev, "%pOFn: invalid clock output count\n", np);
	return -EINVAL;
	}

	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, count),
	GFP_KERNEL);
	if (!clk_data)
	return -ENOMEM;

	clk_data->num = count;
	hws = clk_data->hws;

	is_atomic = handle->is_transport_atomic(handle, &atomic_threshold);

	for (idx = 0; idx < count; idx++) {
	struct scmi_clk *sclk;
	const struct clk_ops *scmi_ops;

	sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
	if (!sclk)
	return -ENOMEM;

	sclk->info = scmi_proto_clk_ops->info_get(ph, idx);
	if (!sclk->info) {
	dev_dbg(dev, "invalid clock info for idx %d\n", idx);
	continue;
	}

	sclk->id = idx;
	sclk->ph = ph;

	/*
	* Note that when transport is atomic but SCMI protocol did not
	* specify (or support) an enable_latency associated with a
	* clock, we default to use atomic operations mode.
	*/
	if (is_atomic &&
	sclk->info->enable_latency <= atomic_threshold)
	scmi_ops = &scmi_atomic_clk_ops;
	else
	scmi_ops = &scmi_clk_ops;

	err = scmi_clk_ops_init(dev, sclk, scmi_ops);
	if (err) {
	dev_err(dev, "failed to register clock %d\n", idx);
	devm_kfree(dev, sclk);
	hws[idx] = NULL;
	} else {
	dev_dbg(dev, "Registered clock:%s%s\n",
	sclk->info->name,
	scmi_ops == &scmi_atomic_clk_ops ?
	" (atomic ops)" : "");
	hws[idx] = &sclk->hw;
	}
	}

	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
	clk_data);
	}

	static const struct scmi_device_id scmi_id_table[] = {
	{ SCMI_PROTOCOL_CLOCK, "clocks" },
	{ },
	};
	MODULE_DEVICE_TABLE(scmi, scmi_id_table);

	static struct scmi_driver scmi_clocks_driver = {
	.name = "scmi-clocks",
	.probe = scmi_clocks_probe,
	.id_table = scmi_id_table,
	};
	module_scmi_driver(scmi_clocks_driver);

	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	MODULE_DESCRIPTION("ARM SCMI clock driver");
	MODULE_LICENSE("GPL v2");