drivers/usb/misc/qcom_eud.c

   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
  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
  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
  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
  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
 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
 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
 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
 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
 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
 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         if (chip->irq < 0)
 209                 return chip->irq;
 210
 211         ret = devm_request_threaded_irq(&pdev->dev, chip->irq, handle_eud_irq,
 212                         handle_eud_irq_thread, IRQF_ONESHOT, NULL, chip);
 213         if (ret)
 214                 return dev_err_probe(chip->dev, ret, "failed to allocate irq\n");
 215
 216         enable_irq_wake(chip->irq);
 217
 218         platform_set_drvdata(pdev, chip);
 219
 220         return 0;
 221 }
 222
 223 static void eud_remove(struct platform_device *pdev)
 224 {
 225         struct eud_chip *chip = platform_get_drvdata(pdev);
 226
 227         if (chip->enabled)
 228                 disable_eud(chip);
 229
 230         device_init_wakeup(&pdev->dev, false);
 231         disable_irq_wake(chip->irq);
 232 }
 233
 234 static const struct of_device_id eud_dt_match[] = {
 235         { .compatible = "qcom,eud" },
 236         { }
 237 };
 238 MODULE_DEVICE_TABLE(of, eud_dt_match);
 239
 240 static struct platform_driver eud_driver = {
 241         .probe  = eud_probe,
 242         .remove = eud_remove,
 243         .driver = {
 244                 .name = "qcom_eud",
 245                 .dev_groups = eud_groups,
 246                 .of_match_table = eud_dt_match,
 247         },
 248 };
 249 module_platform_driver(eud_driver);
 250
 251 MODULE_DESCRIPTION("QTI EUD driver");
 252 MODULE_LICENSE("GPL v2");