xref: /openbmc/u-boot/drivers/clk/at91/clk-usb.c (revision d66ff4ba)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2018 Microhip / Atmel Corporation
4  *               Wenyou.Yang <wenyou.yang@microchip.com>
5  */
6 
7 #include <common.h>
8 #include <clk-uclass.h>
9 #include <dm/device.h>
10 #include <linux/io.h>
11 #include <mach/at91_pmc.h>
12 #include "pmc.h"
13 
14 DECLARE_GLOBAL_DATA_PTR;
15 
16 #define AT91_USB_CLK_SOURCE_MAX	2
17 #define AT91_USB_CLK_MAX_DIV	15
18 
19 struct at91_usb_clk_priv {
20 	u32 num_clksource;
21 };
22 
23 static ulong at91_usb_clk_get_rate(struct clk *clk)
24 {
25 	struct pmc_platdata *plat = dev_get_platdata(clk->dev);
26 	struct at91_pmc *pmc = plat->reg_base;
27 	struct clk source;
28 	u32 tmp, usbdiv;
29 	u8 source_index;
30 	int ret;
31 
32 	tmp = readl(&pmc->pcr);
33 	source_index = (tmp >> AT91_PMC_USB_USBS_OFFSET) &
34 			AT91_PMC_USB_USBS_MASK;
35 	usbdiv = (tmp >> AT91_PMC_USB_DIV_OFFSET) & AT91_PMC_USB_DIV_MASK;
36 
37 	ret = clk_get_by_index(clk->dev, source_index, &source);
38 	if (ret)
39 		return 0;
40 
41 	return clk_get_rate(&source) / (usbdiv + 1);
42 }
43 
44 static ulong at91_usb_clk_set_rate(struct clk *clk, ulong rate)
45 {
46 	struct pmc_platdata *plat = dev_get_platdata(clk->dev);
47 	struct at91_pmc *pmc = plat->reg_base;
48 	struct at91_usb_clk_priv *priv = dev_get_priv(clk->dev);
49 	struct clk source, best_source;
50 	ulong tmp_rate, best_rate = rate, source_rate;
51 	int tmp_diff, best_diff = -1;
52 	u32 div, best_div = 0;
53 	u8 best_source_index = 0;
54 	u8 i;
55 	u32 tmp;
56 	int ret;
57 
58 	for (i = 0; i < priv->num_clksource; i++) {
59 		ret = clk_get_by_index(clk->dev, i, &source);
60 		if (ret)
61 			return ret;
62 
63 		source_rate = clk_get_rate(&source);
64 		if (IS_ERR_VALUE(source_rate))
65 			return source_rate;
66 
67 		for (div = 1; div < AT91_USB_CLK_MAX_DIV + 2; div++) {
68 			tmp_rate = DIV_ROUND_CLOSEST(source_rate, div);
69 			tmp_diff = abs(rate - tmp_rate);
70 
71 			if (best_diff < 0 || best_diff > tmp_diff) {
72 				best_rate = tmp_rate;
73 				best_diff = tmp_diff;
74 
75 				best_div = div - 1;
76 				best_source = source;
77 				best_source_index = i;
78 			}
79 
80 			if (!best_diff || tmp_rate < rate)
81 				break;
82 		}
83 
84 		if (!best_diff)
85 			break;
86 	}
87 
88 	debug("AT91 USB: best sourc: %s, best_rate = %ld, best_div = %d\n",
89 	      best_source.dev->name, best_rate, best_div);
90 
91 	ret = clk_enable(&best_source);
92 	if (ret)
93 		return ret;
94 
95 	tmp = AT91_PMC_USB_USBS_(best_source_index) |
96 	      AT91_PMC_USB_DIV_(best_div);
97 	writel(tmp, &pmc->usb);
98 
99 	return 0;
100 }
101 
102 static struct clk_ops at91_usb_clk_ops = {
103 	.get_rate = at91_usb_clk_get_rate,
104 	.set_rate = at91_usb_clk_set_rate,
105 };
106 
107 static int at91_usb_clk_ofdata_to_platdata(struct udevice *dev)
108 {
109 	struct at91_usb_clk_priv *priv = dev_get_priv(dev);
110 	u32 cells[AT91_USB_CLK_SOURCE_MAX];
111 	u32 num_clksource;
112 
113 	num_clksource = fdtdec_get_int_array_count(gd->fdt_blob,
114 						   dev_of_offset(dev),
115 						   "clocks", cells,
116 						   AT91_USB_CLK_SOURCE_MAX);
117 
118 	if (!num_clksource)
119 		return -1;
120 
121 	priv->num_clksource = num_clksource;
122 
123 	return 0;
124 }
125 
126 static int at91_usb_clk_probe(struct udevice *dev)
127 {
128 	return at91_pmc_core_probe(dev);
129 }
130 
131 static const struct udevice_id at91_usb_clk_match[] = {
132 	{ .compatible = "atmel,at91sam9x5-clk-usb" },
133 	{}
134 };
135 
136 U_BOOT_DRIVER(at91_usb_clk) = {
137 	.name = "at91-usb-clk",
138 	.id = UCLASS_CLK,
139 	.of_match = at91_usb_clk_match,
140 	.probe = at91_usb_clk_probe,
141 	.ofdata_to_platdata = at91_usb_clk_ofdata_to_platdata,
142 	.priv_auto_alloc_size = sizeof(struct at91_usb_clk_priv),
143 	.platdata_auto_alloc_size = sizeof(struct pmc_platdata),
144 	.ops = &at91_usb_clk_ops,
145 };
146