Merge tag 'for-4.17-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...
[linux-2.6-microblaze.git] / drivers / clk / clk-scmi.c
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
175         return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
176                                            clk_data);
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,
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");