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
at91_usb_clk_get_rate(struct clk * clk)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
at91_usb_clk_set_rate(struct clk * clk,ulong rate)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
at91_usb_clk_ofdata_to_platdata(struct udevice * dev)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
at91_usb_clk_probe(struct udevice * dev)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