Merge branch 'clk-stm32mp1' into clk-fixes
[linux-2.6-block.git] / drivers / clk / clk-scmi.c
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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Control and Power Interface (SCMI) Protocol based clock driver
4 *
5 * Copyright (C) 2018 ARM Ltd.
6 */
7
8#include <linux/clk-provider.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/of.h>
12#include <linux/module.h>
13#include <linux/scmi_protocol.h>
14#include <asm/div64.h>
15
16struct scmi_clk {
17 u32 id;
18 struct clk_hw hw;
19 const struct scmi_clock_info *info;
20 const struct scmi_handle *handle;
21};
22
23#define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw)
24
25static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
26 unsigned long parent_rate)
27{
28 int ret;
29 u64 rate;
30 struct scmi_clk *clk = to_scmi_clk(hw);
31
32 ret = clk->handle->clk_ops->rate_get(clk->handle, clk->id, &rate);
33 if (ret)
34 return 0;
35 return rate;
36}
37
38static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
39 unsigned long *parent_rate)
40{
41 int step;
42 u64 fmin, fmax, ftmp;
43 struct scmi_clk *clk = to_scmi_clk(hw);
44
45 /*
46 * We can't figure out what rate it will be, so just return the
47 * rate back to the caller. scmi_clk_recalc_rate() will be called
48 * after the rate is set and we'll know what rate the clock is
49 * running at then.
50 */
51 if (clk->info->rate_discrete)
52 return rate;
53
54 fmin = clk->info->range.min_rate;
55 fmax = clk->info->range.max_rate;
56 if (rate <= fmin)
57 return fmin;
58 else if (rate >= fmax)
59 return fmax;
60
61 ftmp = rate - fmin;
62 ftmp += clk->info->range.step_size - 1; /* to round up */
63 step = do_div(ftmp, clk->info->range.step_size);
64
65 return step * clk->info->range.step_size + fmin;
66}
67
68static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
69 unsigned long parent_rate)
70{
71 struct scmi_clk *clk = to_scmi_clk(hw);
72
73 return clk->handle->clk_ops->rate_set(clk->handle, clk->id, 0, rate);
74}
75
76static int scmi_clk_enable(struct clk_hw *hw)
77{
78 struct scmi_clk *clk = to_scmi_clk(hw);
79
80 return clk->handle->clk_ops->enable(clk->handle, clk->id);
81}
82
83static void scmi_clk_disable(struct clk_hw *hw)
84{
85 struct scmi_clk *clk = to_scmi_clk(hw);
86
87 clk->handle->clk_ops->disable(clk->handle, clk->id);
88}
89
90static const struct clk_ops scmi_clk_ops = {
91 .recalc_rate = scmi_clk_recalc_rate,
92 .round_rate = scmi_clk_round_rate,
93 .set_rate = scmi_clk_set_rate,
94 /*
95 * We can't provide enable/disable callback as we can't perform the same
96 * in atomic context. Since the clock framework provides standard API
97 * clk_prepare_enable that helps cases using clk_enable in non-atomic
98 * context, it should be fine providing prepare/unprepare.
99 */
100 .prepare = scmi_clk_enable,
101 .unprepare = scmi_clk_disable,
102};
103
104static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk)
105{
106 int ret;
107 struct clk_init_data init = {
108 .flags = CLK_GET_RATE_NOCACHE,
109 .num_parents = 0,
110 .ops = &scmi_clk_ops,
111 .name = sclk->info->name,
112 };
113
114 sclk->hw.init = &init;
115 ret = devm_clk_hw_register(dev, &sclk->hw);
116 if (!ret)
117 clk_hw_set_rate_range(&sclk->hw, sclk->info->range.min_rate,
118 sclk->info->range.max_rate);
119 return ret;
120}
121
122static int scmi_clocks_probe(struct scmi_device *sdev)
123{
124 int idx, count, err;
125 struct clk_hw **hws;
126 struct clk_hw_onecell_data *clk_data;
127 struct device *dev = &sdev->dev;
128 struct device_node *np = dev->of_node;
129 const struct scmi_handle *handle = sdev->handle;
130
131 if (!handle || !handle->clk_ops)
132 return -ENODEV;
133
134 count = handle->clk_ops->count_get(handle);
135 if (count < 0) {
136 dev_err(dev, "%s: invalid clock output count\n", np->name);
137 return -EINVAL;
138 }
139
140 clk_data = devm_kzalloc(dev, sizeof(*clk_data) +
141 sizeof(*clk_data->hws) * count, GFP_KERNEL);
142 if (!clk_data)
143 return -ENOMEM;
144
145 clk_data->num = count;
146 hws = clk_data->hws;
147
148 for (idx = 0; idx < count; idx++) {
149 struct scmi_clk *sclk;
150
151 sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
152 if (!sclk)
153 return -ENOMEM;
154
155 sclk->info = handle->clk_ops->info_get(handle, idx);
156 if (!sclk->info) {
157 dev_dbg(dev, "invalid clock info for idx %d\n", idx);
158 continue;
159 }
160
161 sclk->id = idx;
162 sclk->handle = handle;
163
164 err = scmi_clk_ops_init(dev, sclk);
165 if (err) {
166 dev_err(dev, "failed to register clock %d\n", idx);
167 devm_kfree(dev, sclk);
168 hws[idx] = NULL;
169 } else {
170 dev_dbg(dev, "Registered clock:%s\n", sclk->info->name);
171 hws[idx] = &sclk->hw;
172 }
173 }
174
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175 return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
176 clk_data);
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177}
178
179static const struct scmi_device_id scmi_id_table[] = {
180 { SCMI_PROTOCOL_CLOCK },
181 { },
182};
183MODULE_DEVICE_TABLE(scmi, scmi_id_table);
184
185static struct scmi_driver scmi_clocks_driver = {
186 .name = "scmi-clocks",
187 .probe = scmi_clocks_probe,
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188 .id_table = scmi_id_table,
189};
190module_scmi_driver(scmi_clocks_driver);
191
192MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
193MODULE_DESCRIPTION("ARM SCMI clock driver");
194MODULE_LICENSE("GPL v2");