summaryrefslogtreecommitdiff
path: root/drivers/clk/clk-scmi.c
blob: 488c21376b555daaa2487e31b6037de3ae539c46 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
// SPDX-License-Identifier: GPL-2.0
/*
 * System Control and Power Interface (SCMI) Protocol based clock driver
 *
 * Copyright (C) 2018 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>

struct scmi_clk {
	u32 id;
	struct clk_hw hw;
	const struct scmi_clock_info *info;
	const struct scmi_handle *handle;
};

#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 = clk->handle->clk_ops->rate_get(clk->handle, 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)
{
	int step;
	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 */
	step = do_div(ftmp, clk->info->range.step_size);

	return step * 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 clk->handle->clk_ops->rate_set(clk->handle, clk->id, 0, rate);
}

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

	return clk->handle->clk_ops->enable(clk->handle, clk->id);
}

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

	clk->handle->clk_ops->disable(clk->handle, clk->id);
}

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,
	/*
	 * We can't provide enable/disable callback as we can't perform the same
	 * in atomic context. Since the clock framework provides standard API
	 * clk_prepare_enable that helps cases using clk_enable in non-atomic
	 * context, it should be fine providing prepare/unprepare.
	 */
	.prepare = scmi_clk_enable,
	.unprepare = scmi_clk_disable,
};

static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk)
{
	int ret;
	struct clk_init_data init = {
		.flags = CLK_GET_RATE_NOCACHE,
		.num_parents = 0,
		.ops = &scmi_clk_ops,
		.name = sclk->info->name,
	};

	sclk->hw.init = &init;
	ret = devm_clk_hw_register(dev, &sclk->hw);
	if (!ret)
		clk_hw_set_rate_range(&sclk->hw, sclk->info->range.min_rate,
				      sclk->info->range.max_rate);
	return ret;
}

static int scmi_clocks_probe(struct scmi_device *sdev)
{
	int idx, count, err;
	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;

	if (!handle || !handle->clk_ops)
		return -ENODEV;

	count = handle->clk_ops->count_get(handle);
	if (count < 0) {
		dev_err(dev, "%s: invalid clock output count\n", np->name);
		return -EINVAL;
	}

	clk_data = devm_kzalloc(dev, sizeof(*clk_data) +
				sizeof(*clk_data->hws) * count, GFP_KERNEL);
	if (!clk_data)
		return -ENOMEM;

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

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

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

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

		sclk->id = idx;
		sclk->handle = handle;

		err = scmi_clk_ops_init(dev, sclk);
		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\n", sclk->info->name);
			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 },
	{ },
};
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");