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6d6a1d82 SH |
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 | ||
16 | struct 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 | ||
25 | static 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 | ||
38 | static 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 | ||
68 | static 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 | ||
76 | static 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 | ||
83 | static 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 | ||
90 | static 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 | ||
104 | static 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 | ||
122 | static 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 | ||
7f9badfc SH |
175 | return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, |
176 | clk_data); | |
6d6a1d82 SH |
177 | } |
178 | ||
179 | static const struct scmi_device_id scmi_id_table[] = { | |
180 | { SCMI_PROTOCOL_CLOCK }, | |
181 | { }, | |
182 | }; | |
183 | MODULE_DEVICE_TABLE(scmi, scmi_id_table); | |
184 | ||
185 | static struct scmi_driver scmi_clocks_driver = { | |
186 | .name = "scmi-clocks", | |
187 | .probe = scmi_clocks_probe, | |
6d6a1d82 SH |
188 | .id_table = scmi_id_table, |
189 | }; | |
190 | module_scmi_driver(scmi_clocks_driver); | |
191 | ||
192 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); | |
193 | MODULE_DESCRIPTION("ARM SCMI clock driver"); | |
194 | MODULE_LICENSE("GPL v2"); |