1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * cdns3-ti.c - TI specific Glue layer for Cadence USB Controller
4  *
5  * Copyright (C) 2019 Texas Instruments Incorporated - https://www.ti.com
6  */
7 
8 #include <linux/bits.h>
9 #include <linux/clk.h>
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/interrupt.h>
13 #include <linux/platform_device.h>
14 #include <linux/dma-mapping.h>
15 #include <linux/io.h>
16 #include <linux/of_platform.h>
17 #include <linux/pm_runtime.h>
18 
19 /* USB Wrapper register offsets */
20 #define USBSS_PID		0x0
21 #define	USBSS_W1		0x4
22 #define USBSS_STATIC_CONFIG	0x8
23 #define USBSS_PHY_TEST		0xc
24 #define	USBSS_DEBUG_CTRL	0x10
25 #define	USBSS_DEBUG_INFO	0x14
26 #define	USBSS_DEBUG_LINK_STATE	0x18
27 #define	USBSS_DEVICE_CTRL	0x1c
28 
29 /* Wrapper 1 register bits */
30 #define USBSS_W1_PWRUP_RST		BIT(0)
31 #define USBSS_W1_OVERCURRENT_SEL	BIT(8)
32 #define USBSS_W1_MODESTRAP_SEL		BIT(9)
33 #define USBSS_W1_OVERCURRENT		BIT(16)
34 #define USBSS_W1_MODESTRAP_MASK		GENMASK(18, 17)
35 #define USBSS_W1_MODESTRAP_SHIFT	17
36 #define USBSS_W1_USB2_ONLY		BIT(19)
37 
38 /* Static config register bits */
39 #define USBSS1_STATIC_PLL_REF_SEL_MASK	GENMASK(8, 5)
40 #define USBSS1_STATIC_PLL_REF_SEL_SHIFT	5
41 #define USBSS1_STATIC_LOOPBACK_MODE_MASK	GENMASK(4, 3)
42 #define USBSS1_STATIC_LOOPBACK_MODE_SHIFT	3
43 #define USBSS1_STATIC_VBUS_SEL_MASK	GENMASK(2, 1)
44 #define USBSS1_STATIC_VBUS_SEL_SHIFT	1
45 #define USBSS1_STATIC_LANE_REVERSE	BIT(0)
46 
47 /* Modestrap modes */
48 enum modestrap_mode { USBSS_MODESTRAP_MODE_NONE,
49 		      USBSS_MODESTRAP_MODE_HOST,
50 		      USBSS_MODESTRAP_MODE_PERIPHERAL};
51 
52 struct cdns_ti {
53 	struct device *dev;
54 	void __iomem *usbss;
55 	unsigned usb2_only:1;
56 	unsigned vbus_divider:1;
57 	struct clk *usb2_refclk;
58 	struct clk *lpm_clk;
59 };
60 
61 static const int cdns_ti_rate_table[] = {	/* in KHZ */
62 	9600,
63 	10000,
64 	12000,
65 	19200,
66 	20000,
67 	24000,
68 	25000,
69 	26000,
70 	38400,
71 	40000,
72 	58000,
73 	50000,
74 	52000,
75 };
76 
cdns_ti_readl(struct cdns_ti * data,u32 offset)77 static inline u32 cdns_ti_readl(struct cdns_ti *data, u32 offset)
78 {
79 	return readl(data->usbss + offset);
80 }
81 
cdns_ti_writel(struct cdns_ti * data,u32 offset,u32 value)82 static inline void cdns_ti_writel(struct cdns_ti *data, u32 offset, u32 value)
83 {
84 	writel(value, data->usbss + offset);
85 }
86 
cdns_ti_probe(struct platform_device * pdev)87 static int cdns_ti_probe(struct platform_device *pdev)
88 {
89 	struct device *dev = &pdev->dev;
90 	struct device_node *node = pdev->dev.of_node;
91 	struct cdns_ti *data;
92 	int error;
93 	u32 reg;
94 	int rate_code, i;
95 	unsigned long rate;
96 
97 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
98 	if (!data)
99 		return -ENOMEM;
100 
101 	platform_set_drvdata(pdev, data);
102 
103 	data->dev = dev;
104 
105 	data->usbss = devm_platform_ioremap_resource(pdev, 0);
106 	if (IS_ERR(data->usbss)) {
107 		dev_err(dev, "can't map IOMEM resource\n");
108 		return PTR_ERR(data->usbss);
109 	}
110 
111 	data->usb2_refclk = devm_clk_get(dev, "ref");
112 	if (IS_ERR(data->usb2_refclk)) {
113 		dev_err(dev, "can't get usb2_refclk\n");
114 		return PTR_ERR(data->usb2_refclk);
115 	}
116 
117 	data->lpm_clk = devm_clk_get(dev, "lpm");
118 	if (IS_ERR(data->lpm_clk)) {
119 		dev_err(dev, "can't get lpm_clk\n");
120 		return PTR_ERR(data->lpm_clk);
121 	}
122 
123 	rate = clk_get_rate(data->usb2_refclk);
124 	rate /= 1000;	/* To KHz */
125 	for (i = 0; i < ARRAY_SIZE(cdns_ti_rate_table); i++) {
126 		if (cdns_ti_rate_table[i] == rate)
127 			break;
128 	}
129 
130 	if (i == ARRAY_SIZE(cdns_ti_rate_table)) {
131 		dev_err(dev, "unsupported usb2_refclk rate: %lu KHz\n", rate);
132 		return -EINVAL;
133 	}
134 
135 	rate_code = i;
136 
137 	pm_runtime_enable(dev);
138 	error = pm_runtime_get_sync(dev);
139 	if (error < 0) {
140 		dev_err(dev, "pm_runtime_get_sync failed: %d\n", error);
141 		goto err;
142 	}
143 
144 	/* assert RESET */
145 	reg = cdns_ti_readl(data, USBSS_W1);
146 	reg &= ~USBSS_W1_PWRUP_RST;
147 	cdns_ti_writel(data, USBSS_W1, reg);
148 
149 	/* set static config */
150 	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
151 	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
152 	reg |= rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
153 
154 	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
155 	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
156 	if (data->vbus_divider)
157 		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
158 
159 	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
160 	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
161 
162 	/* set USB2_ONLY mode if requested */
163 	reg = cdns_ti_readl(data, USBSS_W1);
164 	data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
165 	if (data->usb2_only)
166 		reg |= USBSS_W1_USB2_ONLY;
167 
168 	/* set default modestrap */
169 	reg |= USBSS_W1_MODESTRAP_SEL;
170 	reg &= ~USBSS_W1_MODESTRAP_MASK;
171 	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
172 	cdns_ti_writel(data, USBSS_W1, reg);
173 
174 	/* de-assert RESET */
175 	reg |= USBSS_W1_PWRUP_RST;
176 	cdns_ti_writel(data, USBSS_W1, reg);
177 
178 	error = of_platform_populate(node, NULL, NULL, dev);
179 	if (error) {
180 		dev_err(dev, "failed to create children: %d\n", error);
181 		goto err;
182 	}
183 
184 	return 0;
185 
186 err:
187 	pm_runtime_put_sync(data->dev);
188 	pm_runtime_disable(data->dev);
189 
190 	return error;
191 }
192 
cdns_ti_remove_core(struct device * dev,void * c)193 static int cdns_ti_remove_core(struct device *dev, void *c)
194 {
195 	struct platform_device *pdev = to_platform_device(dev);
196 
197 	platform_device_unregister(pdev);
198 
199 	return 0;
200 }
201 
cdns_ti_remove(struct platform_device * pdev)202 static int cdns_ti_remove(struct platform_device *pdev)
203 {
204 	struct device *dev = &pdev->dev;
205 
206 	device_for_each_child(dev, NULL, cdns_ti_remove_core);
207 	pm_runtime_put_sync(dev);
208 	pm_runtime_disable(dev);
209 
210 	platform_set_drvdata(pdev, NULL);
211 
212 	return 0;
213 }
214 
215 static const struct of_device_id cdns_ti_of_match[] = {
216 	{ .compatible = "ti,j721e-usb", },
217 	{ .compatible = "ti,am64-usb", },
218 	{},
219 };
220 MODULE_DEVICE_TABLE(of, cdns_ti_of_match);
221 
222 static struct platform_driver cdns_ti_driver = {
223 	.probe		= cdns_ti_probe,
224 	.remove		= cdns_ti_remove,
225 	.driver		= {
226 		.name	= "cdns3-ti",
227 		.of_match_table	= cdns_ti_of_match,
228 	},
229 };
230 
231 module_platform_driver(cdns_ti_driver);
232 
233 MODULE_ALIAS("platform:cdns3-ti");
234 MODULE_AUTHOR("Roger Quadros <rogerq@ti.com>");
235 MODULE_LICENSE("GPL v2");
236 MODULE_DESCRIPTION("Cadence USB3 TI Glue Layer");
237