1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Lantiq XWAY SoC RCU module based USB 1.1/2.0 PHY driver
4  *
5  * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
6  * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/mfd/syscon.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/of_device.h>
16 #include <linux/phy/phy.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19 #include <linux/regmap.h>
20 #include <linux/reset.h>
21 
22 /* Transmitter HS Pre-Emphasis Enable */
23 #define RCU_CFG1_TX_PEE		BIT(0)
24 /* Disconnect Threshold */
25 #define RCU_CFG1_DIS_THR_MASK	0x00038000
26 #define RCU_CFG1_DIS_THR_SHIFT	15
27 
28 struct ltq_rcu_usb2_bits {
29 	u8 hostmode;
30 	u8 slave_endianness;
31 	u8 host_endianness;
32 	bool have_ana_cfg;
33 };
34 
35 struct ltq_rcu_usb2_priv {
36 	struct regmap			*regmap;
37 	unsigned int			phy_reg_offset;
38 	unsigned int			ana_cfg1_reg_offset;
39 	const struct ltq_rcu_usb2_bits	*reg_bits;
40 	struct device			*dev;
41 	struct phy			*phy;
42 	struct clk			*phy_gate_clk;
43 	struct reset_control		*ctrl_reset;
44 	struct reset_control		*phy_reset;
45 };
46 
47 static const struct ltq_rcu_usb2_bits xway_rcu_usb2_reg_bits = {
48 	.hostmode = 11,
49 	.slave_endianness = 9,
50 	.host_endianness = 10,
51 	.have_ana_cfg = false,
52 };
53 
54 static const struct ltq_rcu_usb2_bits xrx100_rcu_usb2_reg_bits = {
55 	.hostmode = 11,
56 	.slave_endianness = 17,
57 	.host_endianness = 10,
58 	.have_ana_cfg = false,
59 };
60 
61 static const struct ltq_rcu_usb2_bits xrx200_rcu_usb2_reg_bits = {
62 	.hostmode = 11,
63 	.slave_endianness = 9,
64 	.host_endianness = 10,
65 	.have_ana_cfg = true,
66 };
67 
68 static const struct of_device_id ltq_rcu_usb2_phy_of_match[] = {
69 	{
70 		.compatible = "lantiq,ase-usb2-phy",
71 		.data = &xway_rcu_usb2_reg_bits,
72 	},
73 	{
74 		.compatible = "lantiq,danube-usb2-phy",
75 		.data = &xway_rcu_usb2_reg_bits,
76 	},
77 	{
78 		.compatible = "lantiq,xrx100-usb2-phy",
79 		.data = &xrx100_rcu_usb2_reg_bits,
80 	},
81 	{
82 		.compatible = "lantiq,xrx200-usb2-phy",
83 		.data = &xrx200_rcu_usb2_reg_bits,
84 	},
85 	{
86 		.compatible = "lantiq,xrx300-usb2-phy",
87 		.data = &xrx200_rcu_usb2_reg_bits,
88 	},
89 	{ },
90 };
91 MODULE_DEVICE_TABLE(of, ltq_rcu_usb2_phy_of_match);
92 
ltq_rcu_usb2_phy_init(struct phy * phy)93 static int ltq_rcu_usb2_phy_init(struct phy *phy)
94 {
95 	struct ltq_rcu_usb2_priv *priv = phy_get_drvdata(phy);
96 
97 	if (priv->reg_bits->have_ana_cfg) {
98 		regmap_update_bits(priv->regmap, priv->ana_cfg1_reg_offset,
99 			RCU_CFG1_TX_PEE, RCU_CFG1_TX_PEE);
100 		regmap_update_bits(priv->regmap, priv->ana_cfg1_reg_offset,
101 			RCU_CFG1_DIS_THR_MASK, 7 << RCU_CFG1_DIS_THR_SHIFT);
102 	}
103 
104 	/* Configure core to host mode */
105 	regmap_update_bits(priv->regmap, priv->phy_reg_offset,
106 			   BIT(priv->reg_bits->hostmode), 0);
107 
108 	/* Select DMA endianness (Host-endian: big-endian) */
109 	regmap_update_bits(priv->regmap, priv->phy_reg_offset,
110 		BIT(priv->reg_bits->slave_endianness), 0);
111 	regmap_update_bits(priv->regmap, priv->phy_reg_offset,
112 		BIT(priv->reg_bits->host_endianness),
113 		BIT(priv->reg_bits->host_endianness));
114 
115 	return 0;
116 }
117 
ltq_rcu_usb2_phy_power_on(struct phy * phy)118 static int ltq_rcu_usb2_phy_power_on(struct phy *phy)
119 {
120 	struct ltq_rcu_usb2_priv *priv = phy_get_drvdata(phy);
121 	struct device *dev = priv->dev;
122 	int ret;
123 
124 	reset_control_deassert(priv->phy_reset);
125 
126 	ret = clk_prepare_enable(priv->phy_gate_clk);
127 	if (ret) {
128 		dev_err(dev, "failed to enable PHY gate\n");
129 		return ret;
130 	}
131 
132 	/*
133 	 * at least the xrx200 usb2 phy requires some extra time to be
134 	 * operational after enabling the clock
135 	 */
136 	usleep_range(100, 200);
137 
138 	return ret;
139 }
140 
ltq_rcu_usb2_phy_power_off(struct phy * phy)141 static int ltq_rcu_usb2_phy_power_off(struct phy *phy)
142 {
143 	struct ltq_rcu_usb2_priv *priv = phy_get_drvdata(phy);
144 
145 	reset_control_assert(priv->phy_reset);
146 
147 	clk_disable_unprepare(priv->phy_gate_clk);
148 
149 	return 0;
150 }
151 
152 static const struct phy_ops ltq_rcu_usb2_phy_ops = {
153 	.init		= ltq_rcu_usb2_phy_init,
154 	.power_on	= ltq_rcu_usb2_phy_power_on,
155 	.power_off	= ltq_rcu_usb2_phy_power_off,
156 	.owner		= THIS_MODULE,
157 };
158 
ltq_rcu_usb2_of_parse(struct ltq_rcu_usb2_priv * priv,struct platform_device * pdev)159 static int ltq_rcu_usb2_of_parse(struct ltq_rcu_usb2_priv *priv,
160 				 struct platform_device *pdev)
161 {
162 	struct device *dev = priv->dev;
163 	const __be32 *offset;
164 
165 	priv->reg_bits = of_device_get_match_data(dev);
166 
167 	priv->regmap = syscon_node_to_regmap(dev->of_node->parent);
168 	if (IS_ERR(priv->regmap)) {
169 		dev_err(dev, "Failed to lookup RCU regmap\n");
170 		return PTR_ERR(priv->regmap);
171 	}
172 
173 	offset = of_get_address(dev->of_node, 0, NULL, NULL);
174 	if (!offset) {
175 		dev_err(dev, "Failed to get RCU PHY reg offset\n");
176 		return -ENOENT;
177 	}
178 	priv->phy_reg_offset = __be32_to_cpu(*offset);
179 
180 	if (priv->reg_bits->have_ana_cfg) {
181 		offset = of_get_address(dev->of_node, 1, NULL, NULL);
182 		if (!offset) {
183 			dev_err(dev, "Failed to get RCU ANA CFG1 reg offset\n");
184 			return -ENOENT;
185 		}
186 		priv->ana_cfg1_reg_offset = __be32_to_cpu(*offset);
187 	}
188 
189 	priv->phy_gate_clk = devm_clk_get(dev, "phy");
190 	if (IS_ERR(priv->phy_gate_clk)) {
191 		dev_err(dev, "Unable to get USB phy gate clk\n");
192 		return PTR_ERR(priv->phy_gate_clk);
193 	}
194 
195 	priv->ctrl_reset = devm_reset_control_get_shared(dev, "ctrl");
196 	if (IS_ERR(priv->ctrl_reset)) {
197 		if (PTR_ERR(priv->ctrl_reset) != -EPROBE_DEFER)
198 			dev_err(dev, "failed to get 'ctrl' reset\n");
199 		return PTR_ERR(priv->ctrl_reset);
200 	}
201 
202 	priv->phy_reset = devm_reset_control_get_optional(dev, "phy");
203 
204 	return PTR_ERR_OR_ZERO(priv->phy_reset);
205 }
206 
ltq_rcu_usb2_phy_probe(struct platform_device * pdev)207 static int ltq_rcu_usb2_phy_probe(struct platform_device *pdev)
208 {
209 	struct device *dev = &pdev->dev;
210 	struct ltq_rcu_usb2_priv *priv;
211 	struct phy_provider *provider;
212 	int ret;
213 
214 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
215 	if (!priv)
216 		return -ENOMEM;
217 
218 	priv->dev = dev;
219 
220 	ret = ltq_rcu_usb2_of_parse(priv, pdev);
221 	if (ret)
222 		return ret;
223 
224 	/* Reset USB core through reset controller */
225 	reset_control_deassert(priv->ctrl_reset);
226 
227 	reset_control_assert(priv->phy_reset);
228 
229 	priv->phy = devm_phy_create(dev, dev->of_node, &ltq_rcu_usb2_phy_ops);
230 	if (IS_ERR(priv->phy)) {
231 		dev_err(dev, "failed to create PHY\n");
232 		return PTR_ERR(priv->phy);
233 	}
234 
235 	phy_set_drvdata(priv->phy, priv);
236 
237 	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
238 	if (IS_ERR(provider))
239 		return PTR_ERR(provider);
240 
241 	dev_set_drvdata(priv->dev, priv);
242 	return 0;
243 }
244 
245 static struct platform_driver ltq_rcu_usb2_phy_driver = {
246 	.probe	= ltq_rcu_usb2_phy_probe,
247 	.driver = {
248 		.name	= "lantiq-rcu-usb2-phy",
249 		.of_match_table	= ltq_rcu_usb2_phy_of_match,
250 	}
251 };
252 module_platform_driver(ltq_rcu_usb2_phy_driver);
253 
254 MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
255 MODULE_DESCRIPTION("Lantiq XWAY USB2 PHY driver");
256 MODULE_LICENSE("GPL v2");
257