1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * IMG Pistachio USB PHY driver
4 *
5 * Copyright (C) 2015 Google, Inc.
6 */
7
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/mfd/syscon.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/phy/phy.h>
16 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
18
19 #include <dt-bindings/phy/phy-pistachio-usb.h>
20
21 #define USB_PHY_CONTROL1 0x04
22 #define USB_PHY_CONTROL1_FSEL_SHIFT 2
23 #define USB_PHY_CONTROL1_FSEL_MASK 0x7
24
25 #define USB_PHY_STRAP_CONTROL 0x10
26 #define USB_PHY_STRAP_CONTROL_REFCLK_SHIFT 4
27 #define USB_PHY_STRAP_CONTROL_REFCLK_MASK 0x3
28
29 #define USB_PHY_STATUS 0x14
30 #define USB_PHY_STATUS_RX_PHY_CLK BIT(9)
31 #define USB_PHY_STATUS_RX_UTMI_CLK BIT(8)
32 #define USB_PHY_STATUS_VBUS_FAULT BIT(7)
33
34 struct pistachio_usb_phy {
35 struct device *dev;
36 struct regmap *cr_top;
37 struct clk *phy_clk;
38 unsigned int refclk;
39 };
40
41 static const unsigned long fsel_rate_map[] = {
42 9600000,
43 10000000,
44 12000000,
45 19200000,
46 20000000,
47 24000000,
48 0,
49 50000000,
50 };
51
pistachio_usb_phy_power_on(struct phy * phy)52 static int pistachio_usb_phy_power_on(struct phy *phy)
53 {
54 struct pistachio_usb_phy *p_phy = phy_get_drvdata(phy);
55 unsigned long timeout, rate;
56 unsigned int i;
57 int ret;
58
59 ret = clk_prepare_enable(p_phy->phy_clk);
60 if (ret < 0) {
61 dev_err(p_phy->dev, "Failed to enable PHY clock: %d\n", ret);
62 return ret;
63 }
64
65 regmap_update_bits(p_phy->cr_top, USB_PHY_STRAP_CONTROL,
66 USB_PHY_STRAP_CONTROL_REFCLK_MASK <<
67 USB_PHY_STRAP_CONTROL_REFCLK_SHIFT,
68 p_phy->refclk << USB_PHY_STRAP_CONTROL_REFCLK_SHIFT);
69
70 rate = clk_get_rate(p_phy->phy_clk);
71 if (p_phy->refclk == REFCLK_XO_CRYSTAL && rate != 12000000) {
72 dev_err(p_phy->dev, "Unsupported rate for XO crystal: %ld\n",
73 rate);
74 ret = -EINVAL;
75 goto disable_clk;
76 }
77
78 for (i = 0; i < ARRAY_SIZE(fsel_rate_map); i++) {
79 if (rate == fsel_rate_map[i])
80 break;
81 }
82 if (i == ARRAY_SIZE(fsel_rate_map)) {
83 dev_err(p_phy->dev, "Unsupported clock rate: %lu\n", rate);
84 ret = -EINVAL;
85 goto disable_clk;
86 }
87
88 regmap_update_bits(p_phy->cr_top, USB_PHY_CONTROL1,
89 USB_PHY_CONTROL1_FSEL_MASK <<
90 USB_PHY_CONTROL1_FSEL_SHIFT,
91 i << USB_PHY_CONTROL1_FSEL_SHIFT);
92
93 timeout = jiffies + msecs_to_jiffies(200);
94 while (time_before(jiffies, timeout)) {
95 unsigned int val;
96
97 regmap_read(p_phy->cr_top, USB_PHY_STATUS, &val);
98 if (val & USB_PHY_STATUS_VBUS_FAULT) {
99 dev_err(p_phy->dev, "VBUS fault detected\n");
100 ret = -EIO;
101 goto disable_clk;
102 }
103 if ((val & USB_PHY_STATUS_RX_PHY_CLK) &&
104 (val & USB_PHY_STATUS_RX_UTMI_CLK))
105 return 0;
106 usleep_range(1000, 1500);
107 }
108
109 dev_err(p_phy->dev, "Timed out waiting for PHY to power on\n");
110 ret = -ETIMEDOUT;
111
112 disable_clk:
113 clk_disable_unprepare(p_phy->phy_clk);
114 return ret;
115 }
116
pistachio_usb_phy_power_off(struct phy * phy)117 static int pistachio_usb_phy_power_off(struct phy *phy)
118 {
119 struct pistachio_usb_phy *p_phy = phy_get_drvdata(phy);
120
121 clk_disable_unprepare(p_phy->phy_clk);
122
123 return 0;
124 }
125
126 static const struct phy_ops pistachio_usb_phy_ops = {
127 .power_on = pistachio_usb_phy_power_on,
128 .power_off = pistachio_usb_phy_power_off,
129 .owner = THIS_MODULE,
130 };
131
pistachio_usb_phy_probe(struct platform_device * pdev)132 static int pistachio_usb_phy_probe(struct platform_device *pdev)
133 {
134 struct pistachio_usb_phy *p_phy;
135 struct phy_provider *provider;
136 struct phy *phy;
137 int ret;
138
139 p_phy = devm_kzalloc(&pdev->dev, sizeof(*p_phy), GFP_KERNEL);
140 if (!p_phy)
141 return -ENOMEM;
142 p_phy->dev = &pdev->dev;
143 platform_set_drvdata(pdev, p_phy);
144
145 p_phy->cr_top = syscon_regmap_lookup_by_phandle(p_phy->dev->of_node,
146 "img,cr-top");
147 if (IS_ERR(p_phy->cr_top)) {
148 dev_err(p_phy->dev, "Failed to get CR_TOP registers: %ld\n",
149 PTR_ERR(p_phy->cr_top));
150 return PTR_ERR(p_phy->cr_top);
151 }
152
153 p_phy->phy_clk = devm_clk_get(p_phy->dev, "usb_phy");
154 if (IS_ERR(p_phy->phy_clk)) {
155 dev_err(p_phy->dev, "Failed to get usb_phy clock: %ld\n",
156 PTR_ERR(p_phy->phy_clk));
157 return PTR_ERR(p_phy->phy_clk);
158 }
159
160 ret = of_property_read_u32(p_phy->dev->of_node, "img,refclk",
161 &p_phy->refclk);
162 if (ret < 0) {
163 dev_err(p_phy->dev, "No reference clock selector specified\n");
164 return ret;
165 }
166
167 phy = devm_phy_create(p_phy->dev, NULL, &pistachio_usb_phy_ops);
168 if (IS_ERR(phy)) {
169 dev_err(p_phy->dev, "Failed to create PHY: %ld\n",
170 PTR_ERR(phy));
171 return PTR_ERR(phy);
172 }
173 phy_set_drvdata(phy, p_phy);
174
175 provider = devm_of_phy_provider_register(p_phy->dev,
176 of_phy_simple_xlate);
177 if (IS_ERR(provider)) {
178 dev_err(p_phy->dev, "Failed to register PHY provider: %ld\n",
179 PTR_ERR(provider));
180 return PTR_ERR(provider);
181 }
182
183 return 0;
184 }
185
186 static const struct of_device_id pistachio_usb_phy_of_match[] = {
187 { .compatible = "img,pistachio-usb-phy", },
188 { },
189 };
190 MODULE_DEVICE_TABLE(of, pistachio_usb_phy_of_match);
191
192 static struct platform_driver pistachio_usb_phy_driver = {
193 .probe = pistachio_usb_phy_probe,
194 .driver = {
195 .name = "pistachio-usb-phy",
196 .of_match_table = pistachio_usb_phy_of_match,
197 },
198 };
199 module_platform_driver(pistachio_usb_phy_driver);
200
201 MODULE_AUTHOR("Andrew Bresticker <abrestic@chromium.org>");
202 MODULE_DESCRIPTION("IMG Pistachio USB2.0 PHY driver");
203 MODULE_LICENSE("GPL v2");
204