1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2015-2021, The Linux Foundation. All rights reserved.
4 */
5
6 #include <linux/bitops.h>
7 #include <linux/err.h>
8 #include <linux/interrupt.h>
9 #include <linux/io.h>
10 #include <linux/iopoll.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16 #include <linux/sysfs.h>
17 #include <linux/usb/role.h>
18
19 #define EUD_REG_INT1_EN_MASK 0x0024
20 #define EUD_REG_INT_STATUS_1 0x0044
21 #define EUD_REG_CTL_OUT_1 0x0074
22 #define EUD_REG_VBUS_INT_CLR 0x0080
23 #define EUD_REG_CSR_EUD_EN 0x1014
24 #define EUD_REG_SW_ATTACH_DET 0x1018
25 #define EUD_REG_EUD_EN2 0x0000
26
27 #define EUD_ENABLE BIT(0)
28 #define EUD_INT_PET_EUD BIT(0)
29 #define EUD_INT_VBUS BIT(2)
30 #define EUD_INT_SAFE_MODE BIT(4)
31 #define EUD_INT_ALL (EUD_INT_VBUS | EUD_INT_SAFE_MODE)
32
33 struct eud_chip {
34 struct device *dev;
35 struct usb_role_switch *role_sw;
36 void __iomem *base;
37 void __iomem *mode_mgr;
38 unsigned int int_status;
39 int irq;
40 bool enabled;
41 bool usb_attached;
42 };
43
enable_eud(struct eud_chip * priv)44 static int enable_eud(struct eud_chip *priv)
45 {
46 writel(EUD_ENABLE, priv->base + EUD_REG_CSR_EUD_EN);
47 writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
48 priv->base + EUD_REG_INT1_EN_MASK);
49 writel(1, priv->mode_mgr + EUD_REG_EUD_EN2);
50
51 return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
52 }
53
disable_eud(struct eud_chip * priv)54 static void disable_eud(struct eud_chip *priv)
55 {
56 writel(0, priv->base + EUD_REG_CSR_EUD_EN);
57 writel(0, priv->mode_mgr + EUD_REG_EUD_EN2);
58 }
59
enable_show(struct device * dev,struct device_attribute * attr,char * buf)60 static ssize_t enable_show(struct device *dev,
61 struct device_attribute *attr, char *buf)
62 {
63 struct eud_chip *chip = dev_get_drvdata(dev);
64
65 return sysfs_emit(buf, "%d\n", chip->enabled);
66 }
67
enable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)68 static ssize_t enable_store(struct device *dev,
69 struct device_attribute *attr,
70 const char *buf, size_t count)
71 {
72 struct eud_chip *chip = dev_get_drvdata(dev);
73 bool enable;
74 int ret;
75
76 if (kstrtobool(buf, &enable))
77 return -EINVAL;
78
79 if (enable) {
80 ret = enable_eud(chip);
81 if (!ret)
82 chip->enabled = enable;
83 else
84 disable_eud(chip);
85 } else {
86 disable_eud(chip);
87 }
88
89 return count;
90 }
91
92 static DEVICE_ATTR_RW(enable);
93
94 static struct attribute *eud_attrs[] = {
95 &dev_attr_enable.attr,
96 NULL,
97 };
98 ATTRIBUTE_GROUPS(eud);
99
usb_attach_detach(struct eud_chip * chip)100 static void usb_attach_detach(struct eud_chip *chip)
101 {
102 u32 reg;
103
104 /* read ctl_out_1[4] to find USB attach or detach event */
105 reg = readl(chip->base + EUD_REG_CTL_OUT_1);
106 chip->usb_attached = reg & EUD_INT_SAFE_MODE;
107 }
108
pet_eud(struct eud_chip * chip)109 static void pet_eud(struct eud_chip *chip)
110 {
111 u32 reg;
112 int ret;
113
114 /* When the EUD_INT_PET_EUD in SW_ATTACH_DET is set, the cable has been
115 * disconnected and we need to detach the pet to check if EUD is in safe
116 * mode before attaching again.
117 */
118 reg = readl(chip->base + EUD_REG_SW_ATTACH_DET);
119 if (reg & EUD_INT_PET_EUD) {
120 /* Detach & Attach pet for EUD */
121 writel(0, chip->base + EUD_REG_SW_ATTACH_DET);
122 /* Delay to make sure detach pet is done before attach pet */
123 ret = readl_poll_timeout(chip->base + EUD_REG_SW_ATTACH_DET,
124 reg, (reg == 0), 1, 100);
125 if (ret) {
126 dev_err(chip->dev, "Detach pet failed\n");
127 return;
128 }
129 }
130 /* Attach pet for EUD */
131 writel(EUD_INT_PET_EUD, chip->base + EUD_REG_SW_ATTACH_DET);
132 }
133
handle_eud_irq(int irq,void * data)134 static irqreturn_t handle_eud_irq(int irq, void *data)
135 {
136 struct eud_chip *chip = data;
137 u32 reg;
138
139 reg = readl(chip->base + EUD_REG_INT_STATUS_1);
140 switch (reg & EUD_INT_ALL) {
141 case EUD_INT_VBUS:
142 usb_attach_detach(chip);
143 return IRQ_WAKE_THREAD;
144 case EUD_INT_SAFE_MODE:
145 pet_eud(chip);
146 return IRQ_HANDLED;
147 default:
148 return IRQ_NONE;
149 }
150 }
151
handle_eud_irq_thread(int irq,void * data)152 static irqreturn_t handle_eud_irq_thread(int irq, void *data)
153 {
154 struct eud_chip *chip = data;
155 int ret;
156
157 if (chip->usb_attached)
158 ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_DEVICE);
159 else
160 ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_HOST);
161 if (ret)
162 dev_err(chip->dev, "failed to set role switch\n");
163
164 /* set and clear vbus_int_clr[0] to clear interrupt */
165 writel(BIT(0), chip->base + EUD_REG_VBUS_INT_CLR);
166 writel(0, chip->base + EUD_REG_VBUS_INT_CLR);
167
168 return IRQ_HANDLED;
169 }
170
eud_role_switch_release(void * data)171 static void eud_role_switch_release(void *data)
172 {
173 struct eud_chip *chip = data;
174
175 usb_role_switch_put(chip->role_sw);
176 }
177
eud_probe(struct platform_device * pdev)178 static int eud_probe(struct platform_device *pdev)
179 {
180 struct eud_chip *chip;
181 int ret;
182
183 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
184 if (!chip)
185 return -ENOMEM;
186
187 chip->dev = &pdev->dev;
188
189 chip->role_sw = usb_role_switch_get(&pdev->dev);
190 if (IS_ERR(chip->role_sw))
191 return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
192 "failed to get role switch\n");
193
194 ret = devm_add_action_or_reset(chip->dev, eud_role_switch_release, chip);
195 if (ret)
196 return dev_err_probe(chip->dev, ret,
197 "failed to add role switch release action\n");
198
199 chip->base = devm_platform_ioremap_resource(pdev, 0);
200 if (IS_ERR(chip->base))
201 return PTR_ERR(chip->base);
202
203 chip->mode_mgr = devm_platform_ioremap_resource(pdev, 1);
204 if (IS_ERR(chip->mode_mgr))
205 return PTR_ERR(chip->mode_mgr);
206
207 chip->irq = platform_get_irq(pdev, 0);
208 ret = devm_request_threaded_irq(&pdev->dev, chip->irq, handle_eud_irq,
209 handle_eud_irq_thread, IRQF_ONESHOT, NULL, chip);
210 if (ret)
211 return dev_err_probe(chip->dev, ret, "failed to allocate irq\n");
212
213 enable_irq_wake(chip->irq);
214
215 platform_set_drvdata(pdev, chip);
216
217 return 0;
218 }
219
eud_remove(struct platform_device * pdev)220 static void eud_remove(struct platform_device *pdev)
221 {
222 struct eud_chip *chip = platform_get_drvdata(pdev);
223
224 if (chip->enabled)
225 disable_eud(chip);
226
227 device_init_wakeup(&pdev->dev, false);
228 disable_irq_wake(chip->irq);
229 }
230
231 static const struct of_device_id eud_dt_match[] = {
232 { .compatible = "qcom,sc7280-eud" },
233 { }
234 };
235 MODULE_DEVICE_TABLE(of, eud_dt_match);
236
237 static struct platform_driver eud_driver = {
238 .probe = eud_probe,
239 .remove_new = eud_remove,
240 .driver = {
241 .name = "qcom_eud",
242 .dev_groups = eud_groups,
243 .of_match_table = eud_dt_match,
244 },
245 };
246 module_platform_driver(eud_driver);
247
248 MODULE_DESCRIPTION("QTI EUD driver");
249 MODULE_LICENSE("GPL v2");
250