1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018 Arm Ltd
4  * Author: Liviu Dudau <liviu.dudau@foss.arm.com>
5  *
6  */
7 #define DEBUG
8 #include <common.h>
9 #include <clk-uclass.h>
10 #include <dm.h>
11 #include <dm/lists.h>
12 #include <errno.h>
13 #include <misc.h>
14 
15 #define CLK_FUNCTION		BIT(20)
16 
17 struct vexpress_osc_clk_priv {
18 	u8 osc;
19 	ulong rate_min;
20 	ulong rate_max;
21 };
22 
23 static ulong vexpress_osc_clk_get_rate(struct clk *clk)
24 {
25 	int err;
26 	u32 data;
27 	struct udevice *vexpress_cfg = dev_get_parent(clk->dev);
28 	struct vexpress_osc_clk_priv *priv = dev_get_priv(clk->dev);
29 
30 	data = CLK_FUNCTION | priv->osc;
31 	err = misc_read(vexpress_cfg, 0, &data, sizeof(data));
32 	if (err < 0)
33 		return err;
34 
35 	return data;
36 }
37 
38 #ifndef CONFIG_SPL_BUILD
39 static ulong vexpress_osc_clk_set_rate(struct clk *clk, ulong rate)
40 {
41 	int err;
42 	u32 buffer[2];
43 	struct udevice *vexpress_cfg = dev_get_parent(clk->dev);
44 	struct vexpress_osc_clk_priv *priv = dev_get_priv(clk->dev);
45 
46 	if (rate < priv->rate_min || rate > priv->rate_max)
47 		return -EINVAL;
48 
49 	/*
50 	 * we are sending the parent the info about the oscillator
51 	 * and the value we want to set
52 	 */
53 	buffer[0] = CLK_FUNCTION | priv->osc;
54 	buffer[1] = rate;
55 	err = misc_write(vexpress_cfg, 0, buffer, 2 * sizeof(u32));
56 	if (err < 0)
57 		return err;
58 
59 	return rate;
60 }
61 #endif
62 
63 static struct clk_ops vexpress_osc_clk_ops = {
64 	.get_rate = vexpress_osc_clk_get_rate,
65 #ifndef CONFIG_SPL_BUILD
66 	.set_rate = vexpress_osc_clk_set_rate,
67 #endif
68 };
69 
70 static int vexpress_osc_clk_probe(struct udevice *dev)
71 {
72 	struct vexpress_osc_clk_priv *priv = dev_get_priv(dev);
73 	u32 values[2];
74 	int err;
75 
76 	err = dev_read_u32_array(dev, "freq-range", values, 2);
77 	if (err)
78 		return err;
79 	priv->rate_min = values[0];
80 	priv->rate_max = values[1];
81 
82 	err = dev_read_u32_array(dev, "arm,vexpress-sysreg,func", values, 2);
83 	if (err)
84 		return err;
85 
86 	if (values[0] != 1) {
87 		dev_err(dev, "Invalid VExpress function for clock, must be '1'");
88 		return -EINVAL;
89 	}
90 	priv->osc = values[1];
91 	debug("clk \"%s%d\", min freq %luHz, max freq %luHz\n", dev->name,
92 	      priv->osc, priv->rate_min, priv->rate_max);
93 
94 	return 0;
95 }
96 
97 static const struct udevice_id vexpress_osc_clk_ids[] = {
98 	{ .compatible = "arm,vexpress-osc", },
99 	{}
100 };
101 
102 U_BOOT_DRIVER(vexpress_osc_clk) = {
103 	.name = "vexpress_osc_clk",
104 	.id = UCLASS_CLK,
105 	.of_match = vexpress_osc_clk_ids,
106 	.ops = &vexpress_osc_clk_ops,
107 	.priv_auto_alloc_size = sizeof(struct vexpress_osc_clk_priv),
108 	.probe = vexpress_osc_clk_probe,
109 };
110