xref: /openbmc/u-boot/drivers/clk/at91/clk-utmi.c (revision b9553986) 
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2016 Atmel Corporation
4  *               Wenyou.Yang <wenyou.yang@atmel.com>
5  */
6 
7 #include <common.h>
8 #include <clk-uclass.h>
9 #include <dm.h>
10 #include <syscon.h>
11 #include <linux/io.h>
12 #include <mach/at91_pmc.h>
13 #include <mach/sama5_sfr.h>
14 #include "pmc.h"
15 
16 /*
17  * The purpose of this clock is to generate a 480 MHz signal. A different
18  * rate can't be configured.
19  */
20 #define UTMI_RATE	480000000
21 
22 static int utmi_clk_enable(struct clk *clk)
23 {
24 	struct pmc_platdata *plat = dev_get_platdata(clk->dev);
25 	struct at91_pmc *pmc = plat->reg_base;
26 	struct clk clk_dev;
27 	ulong clk_rate;
28 	u32 utmi_ref_clk_freq;
29 	u32 tmp;
30 	int err;
31 	int timeout = 2000000;
32 
33 	if (readl(&pmc->sr) & AT91_PMC_LOCKU)
34 		return 0;
35 
36 	/*
37 	 * If mainck rate is different from 12 MHz, we have to configure the
38 	 * FREQ field of the SFR_UTMICKTRIM register to generate properly
39 	 * the utmi clock.
40 	 */
41 	err = clk_get_by_index(clk->dev, 0, &clk_dev);
42 	if (err)
43 		return -EINVAL;
44 
45 	clk_rate = clk_get_rate(&clk_dev);
46 	switch (clk_rate) {
47 	case 12000000:
48 		utmi_ref_clk_freq = 0;
49 		break;
50 	case 16000000:
51 		utmi_ref_clk_freq = 1;
52 		break;
53 	case 24000000:
54 		utmi_ref_clk_freq = 2;
55 		break;
56 	/*
57 	 * Not supported on SAMA5D2 but it's not an issue since MAINCK
58 	 * maximum value is 24 MHz.
59 	 */
60 	case 48000000:
61 		utmi_ref_clk_freq = 3;
62 		break;
63 	default:
64 		printf("UTMICK: unsupported mainck rate\n");
65 		return -EINVAL;
66 	}
67 
68 	if (plat->regmap_sfr) {
69 		err = regmap_read(plat->regmap_sfr, AT91_SFR_UTMICKTRIM, &tmp);
70 		if (err)
71 			return -EINVAL;
72 
73 		tmp &= ~AT91_UTMICKTRIM_FREQ;
74 		tmp |= utmi_ref_clk_freq;
75 		err = regmap_write(plat->regmap_sfr, AT91_SFR_UTMICKTRIM, tmp);
76 		if (err)
77 			return -EINVAL;
78 	} else if (utmi_ref_clk_freq) {
79 		printf("UTMICK: sfr node required\n");
80 		return -EINVAL;
81 	}
82 
83 	tmp = readl(&pmc->uckr);
84 	tmp |= AT91_PMC_UPLLEN |
85 	       AT91_PMC_UPLLCOUNT |
86 	       AT91_PMC_BIASEN;
87 	writel(tmp, &pmc->uckr);
88 
89 	while ((--timeout) && !(readl(&pmc->sr) & AT91_PMC_LOCKU))
90 		;
91 	if (!timeout) {
92 		printf("UTMICK: timeout waiting for UPLL lock\n");
93 		return -ETIMEDOUT;
94 	}
95 
96 	return 0;
97 }
98 
99 static ulong utmi_clk_get_rate(struct clk *clk)
100 {
101 	/* UTMI clk rate is fixed. */
102 	return UTMI_RATE;
103 }
104 
105 static struct clk_ops utmi_clk_ops = {
106 	.enable = utmi_clk_enable,
107 	.get_rate = utmi_clk_get_rate,
108 };
109 
110 static int utmi_clk_ofdata_to_platdata(struct udevice *dev)
111 {
112 	struct pmc_platdata *plat = dev_get_platdata(dev);
113 	struct udevice *syscon;
114 
115 	uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
116 				     "regmap-sfr", &syscon);
117 
118 	if (syscon)
119 		plat->regmap_sfr = syscon_get_regmap(syscon);
120 
121 	return 0;
122 }
123 
124 static int utmi_clk_probe(struct udevice *dev)
125 {
126 	return at91_pmc_core_probe(dev);
127 }
128 
129 static const struct udevice_id utmi_clk_match[] = {
130 	{ .compatible = "atmel,at91sam9x5-clk-utmi" },
131 	{}
132 };
133 
134 U_BOOT_DRIVER(at91sam9x5_utmi_clk) = {
135 	.name = "at91sam9x5-utmi-clk",
136 	.id = UCLASS_CLK,
137 	.of_match = utmi_clk_match,
138 	.probe = utmi_clk_probe,
139 	.ofdata_to_platdata = utmi_clk_ofdata_to_platdata,
140 	.platdata_auto_alloc_size = sizeof(struct pmc_platdata),
141 	.ops = &utmi_clk_ops,
142 };
143