drivers/nxp/clk/s32cc/s32cc_clk_drv.c

/*
 * Copyright 2024 NXP
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
#include <errno.h>

#include <common/debug.h>
#include <drivers/clk.h>
#include <s32cc-clk-modules.h>
#include <s32cc-clk-utils.h>

#define MAX_STACK_DEPTH		(15U)

static int update_stack_depth(unsigned int *depth)
{
	if (*depth == 0U) {
		return -ENOMEM;
	}

	(*depth)--;
	return 0;
}

static int s32cc_clk_enable(unsigned long id)
{
	return -ENOTSUP;
}

static void s32cc_clk_disable(unsigned long id)
{
}

static bool s32cc_clk_is_enabled(unsigned long id)
{
	return false;
}

static unsigned long s32cc_clk_get_rate(unsigned long id)
{
	return 0;
}

static int set_module_rate(const struct s32cc_clk_obj *module,
			   unsigned long rate, unsigned long *orate,
			   unsigned int *depth);

static int set_osc_freq(const struct s32cc_clk_obj *module, unsigned long rate,
			unsigned long *orate, unsigned int *depth)
{
	struct s32cc_osc *osc = s32cc_obj2osc(module);
	int ret;

	ret = update_stack_depth(depth);
	if (ret != 0) {
		return ret;
	}

	if ((osc->freq != 0UL) && (rate != osc->freq)) {
		ERROR("Already initialized oscillator. freq = %lu\n",
		      osc->freq);
		return -EINVAL;
	}

	osc->freq = rate;
	*orate = osc->freq;

	return 0;
}

static int set_clk_freq(const struct s32cc_clk_obj *module, unsigned long rate,
			unsigned long *orate, unsigned int *depth)
{
	const struct s32cc_clk *clk = s32cc_obj2clk(module);
	int ret;

	ret = update_stack_depth(depth);
	if (ret != 0) {
		return ret;
	}

	if ((clk->min_freq != 0UL) && (clk->max_freq != 0UL) &&
	    ((rate < clk->min_freq) || (rate > clk->max_freq))) {
		ERROR("%lu frequency is out of the allowed range: [%lu:%lu]\n",
		      rate, clk->min_freq, clk->max_freq);
		return -EINVAL;
	}

	if (clk->module != NULL) {
		return set_module_rate(clk->module, rate, orate, depth);
	}

	if (clk->pclock != NULL) {
		return set_clk_freq(&clk->pclock->desc, rate, orate, depth);
	}

	return -EINVAL;
}

static int set_module_rate(const struct s32cc_clk_obj *module,
			   unsigned long rate, unsigned long *orate,
			   unsigned int *depth)
{
	int ret = 0;

	ret = update_stack_depth(depth);
	if (ret != 0) {
		return ret;
	}

	switch (module->type) {
	case s32cc_clk_t:
		ret = set_clk_freq(module, rate, orate, depth);
		break;
	case s32cc_osc_t:
		ret = set_osc_freq(module, rate, orate, depth);
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

static int s32cc_clk_set_rate(unsigned long id, unsigned long rate,
			      unsigned long *orate)
{
	unsigned int depth = MAX_STACK_DEPTH;
	const struct s32cc_clk *clk;
	int ret;

	clk = s32cc_get_arch_clk(id);
	if (clk == NULL) {
		return -EINVAL;
	}

	ret = set_module_rate(&clk->desc, rate, orate, &depth);
	if (ret != 0) {
		ERROR("Failed to set frequency (%lu MHz) for clock %lu\n",
		      rate, id);
	}

	return ret;
}

static int s32cc_clk_get_parent(unsigned long id)
{
	return -ENOTSUP;
}

static int s32cc_clk_set_parent(unsigned long id, unsigned long parent_id)
{
	return -ENOTSUP;
}

void s32cc_clk_register_drv(void)
{
	static const struct clk_ops s32cc_clk_ops = {
		.enable		= s32cc_clk_enable,
		.disable	= s32cc_clk_disable,
		.is_enabled	= s32cc_clk_is_enabled,
		.get_rate	= s32cc_clk_get_rate,
		.set_rate	= s32cc_clk_set_rate,
		.get_parent	= s32cc_clk_get_parent,
		.set_parent	= s32cc_clk_set_parent,
	};

	clk_register(&s32cc_clk_ops);
}