drivers/phy/ti/phy-dm816x-usb.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <linux/module.h>
   4 #include <linux/platform_device.h>
   5 #include <linux/regmap.h>
   6
   7 #include <linux/slab.h>
   8 #include <linux/of.h>
   9 #include <linux/io.h>
  10 #include <linux/usb/phy_companion.h>
  11 #include <linux/clk.h>
  12 #include <linux/err.h>
  13 #include <linux/pm_runtime.h>
  14 #include <linux/delay.h>
  15 #include <linux/phy/phy.h>
  16 #include <linux/of_platform.h>
  17
  18 #include <linux/mfd/syscon.h>
  19
  20 /*
  21  * TRM has two sets of USB_CTRL registers.. The correct register bits
  22  * are in TRM section 24.9.8.2 USB_CTRL Register. The TRM documents the
  23  * phy as being SR70LX Synopsys USB 2.0 OTG nanoPHY. It also seems at
  24  * least dm816x rev c ignores writes to USB_CTRL register, but the TI
  25  * kernel is writing to those so it's possible that later revisions
  26  * have worknig USB_CTRL register.
  27  *
  28  * Also note that At least USB_CTRL register seems to be dm816x specific
  29  * according to the TRM. It's possible that USBPHY_CTRL is more generic,
  30  * but that would have to be checked against the SR70LX documentation
  31  * which does not seem to be publicly available.
  32  *
  33  * Finally, the phy on dm814x and am335x is different from dm816x.
  34  */
  35 #define DM816X_USB_CTRL_PHYCLKSRC       BIT(8)  /* 1 = PLL ref clock */
  36 #define DM816X_USB_CTRL_PHYSLEEP1       BIT(1)  /* Enable the first phy */
  37 #define DM816X_USB_CTRL_PHYSLEEP0       BIT(0)  /* Enable the second phy */
  38
  39 #define DM816X_USBPHY_CTRL_TXRISETUNE   1
  40 #define DM816X_USBPHY_CTRL_TXVREFTUNE   0xc
  41 #define DM816X_USBPHY_CTRL_TXPREEMTUNE  0x2
  42
  43 struct dm816x_usb_phy {
  44         struct regmap *syscon;
  45         struct device *dev;
  46         unsigned int instance;
  47         struct clk *refclk;
  48         struct usb_phy phy;
  49         unsigned int usb_ctrl;          /* Shared between phy0 and phy1 */
  50         unsigned int usbphy_ctrl;
  51 };
  52
  53 static int dm816x_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)
  54 {
  55         otg->host = host;
  56         if (!host)
  57                 otg->state = OTG_STATE_UNDEFINED;
  58
  59         return 0;
  60 }
  61
  62 static int dm816x_usb_phy_set_peripheral(struct usb_otg *otg,
  63                                          struct usb_gadget *gadget)
  64 {
  65         otg->gadget = gadget;
  66         if (!gadget)
  67                 otg->state = OTG_STATE_UNDEFINED;
  68
  69         return 0;
  70 }
  71
  72 static int dm816x_usb_phy_init(struct phy *x)
  73 {
  74         struct dm816x_usb_phy *phy = phy_get_drvdata(x);
  75         unsigned int val;
  76
  77         if (clk_get_rate(phy->refclk) != 24000000)
  78                 dev_warn(phy->dev, "nonstandard phy refclk\n");
  79
  80         /* Set PLL ref clock and put phys to sleep */
  81         regmap_update_bits(phy->syscon, phy->usb_ctrl,
  82                            DM816X_USB_CTRL_PHYCLKSRC |
  83                            DM816X_USB_CTRL_PHYSLEEP1 |
  84                            DM816X_USB_CTRL_PHYSLEEP0,
  85                            0);
  86         regmap_read(phy->syscon, phy->usb_ctrl, &val);
  87         if ((val & 3) != 0)
  88                 dev_info(phy->dev,
  89                          "Working dm816x USB_CTRL! (0x%08x)\n",
  90                          val);
  91
  92         /*
  93          * TI kernel sets these values for "symmetrical eye diagram and
  94          * better signal quality" so let's assume somebody checked the
  95          * values with a scope and set them here too.
  96          */
  97         regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
  98         val |= DM816X_USBPHY_CTRL_TXRISETUNE |
  99                 DM816X_USBPHY_CTRL_TXVREFTUNE |
 100                 DM816X_USBPHY_CTRL_TXPREEMTUNE;
 101         regmap_write(phy->syscon, phy->usbphy_ctrl, val);
 102
 103         return 0;
 104 }
 105
 106 static const struct phy_ops ops = {
 107         .init           = dm816x_usb_phy_init,
 108         .owner          = THIS_MODULE,
 109 };
 110
 111 static int __maybe_unused dm816x_usb_phy_runtime_suspend(struct device *dev)
 112 {
 113         struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
 114         unsigned int mask, val;
 115         int error = 0;
 116
 117         mask = BIT(phy->instance);
 118         val = ~BIT(phy->instance);
 119         error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
 120                                    mask, val);
 121         if (error)
 122                 dev_err(phy->dev, "phy%i failed to power off\n",
 123                         phy->instance);
 124         clk_disable(phy->refclk);
 125
 126         return 0;
 127 }
 128
 129 static int __maybe_unused dm816x_usb_phy_runtime_resume(struct device *dev)
 130 {
 131         struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
 132         unsigned int mask, val;
 133         int error;
 134
 135         error = clk_enable(phy->refclk);
 136         if (error)
 137                 return error;
 138
 139         /*
 140          * Note that at least dm816x rev c does not seem to do
 141          * anything with the USB_CTRL register. But let's follow
 142          * what the TI tree is doing in case later revisions use
 143          * USB_CTRL.
 144          */
 145         mask = BIT(phy->instance);
 146         val = BIT(phy->instance);
 147         error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
 148                                    mask, val);
 149         if (error) {
 150                 dev_err(phy->dev, "phy%i failed to power on\n",
 151                         phy->instance);
 152                 clk_disable(phy->refclk);
 153                 return error;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,
 160                             dm816x_usb_phy_runtime_suspend,
 161                             dm816x_usb_phy_runtime_resume,
 162                             NULL);
 163
 164 #ifdef CONFIG_OF
 165 static const struct of_device_id dm816x_usb_phy_id_table[] = {
 166         {
 167                 .compatible = "ti,dm8168-usb-phy",
 168         },
 169         {},
 170 };
 171 MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
 172 #endif
 173
 174 static int dm816x_usb_phy_probe(struct platform_device *pdev)
 175 {
 176         struct dm816x_usb_phy *phy;
 177         struct resource *res;
 178         struct phy *generic_phy;
 179         struct phy_provider *phy_provider;
 180         struct usb_otg *otg;
 181         const struct of_device_id *of_id;
 182         int error;
 183
 184         of_id = of_match_device(of_match_ptr(dm816x_usb_phy_id_table),
 185                                 &pdev->dev);
 186         if (!of_id)
 187                 return -EINVAL;
 188
 189         phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
 190         if (!phy)
 191                 return -ENOMEM;
 192
 193         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 194         if (!res)
 195                 return -ENOENT;
 196
 197         phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
 198                                                       "syscon");
 199         if (IS_ERR(phy->syscon))
 200                 return PTR_ERR(phy->syscon);
 201
 202         /*
 203          * According to sprs614e.pdf, the first usb_ctrl is shared and
 204          * the second instance for usb_ctrl is reserved.. Also the
 205          * register bits are different from earlier TRMs.
 206          */
 207         phy->usb_ctrl = 0x20;
 208         phy->usbphy_ctrl = (res->start & 0xff) + 4;
 209         if (phy->usbphy_ctrl == 0x2c)
 210                 phy->instance = 1;
 211
 212         otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
 213         if (!otg)
 214                 return -ENOMEM;
 215
 216         phy->dev = &pdev->dev;
 217         phy->phy.dev = phy->dev;
 218         phy->phy.label = "dm8168_usb_phy";
 219         phy->phy.otg = otg;
 220         phy->phy.type = USB_PHY_TYPE_USB2;
 221         otg->set_host = dm816x_usb_phy_set_host;
 222         otg->set_peripheral = dm816x_usb_phy_set_peripheral;
 223         otg->usb_phy = &phy->phy;
 224
 225         platform_set_drvdata(pdev, phy);
 226
 227         phy->refclk = devm_clk_get(phy->dev, "refclk");
 228         if (IS_ERR(phy->refclk))
 229                 return PTR_ERR(phy->refclk);
 230         error = clk_prepare(phy->refclk);
 231         if (error)
 232                 return error;
 233
 234         pm_runtime_enable(phy->dev);
 235         generic_phy = devm_phy_create(phy->dev, NULL, &ops);
 236         if (IS_ERR(generic_phy)) {
 237                 error = PTR_ERR(generic_phy);
 238                 goto clk_unprepare;
 239         }
 240
 241         phy_set_drvdata(generic_phy, phy);
 242
 243         phy_provider = devm_of_phy_provider_register(phy->dev,
 244                                                      of_phy_simple_xlate);
 245         if (IS_ERR(phy_provider)) {
 246                 error = PTR_ERR(phy_provider);
 247                 goto clk_unprepare;
 248         }
 249
 250         usb_add_phy_dev(&phy->phy);
 251
 252         return 0;
 253
 254 clk_unprepare:
 255         pm_runtime_disable(phy->dev);
 256         clk_unprepare(phy->refclk);
 257         return error;
 258 }
 259
 260 static void dm816x_usb_phy_remove(struct platform_device *pdev)
 261 {
 262         struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);
 263
 264         usb_remove_phy(&phy->phy);
 265         pm_runtime_disable(phy->dev);
 266         clk_unprepare(phy->refclk);
 267 }
 268
 269 static struct platform_driver dm816x_usb_phy_driver = {
 270         .probe          = dm816x_usb_phy_probe,
 271         .remove_new     = dm816x_usb_phy_remove,
 272         .driver         = {
 273                 .name   = "dm816x-usb-phy",
 274                 .pm     = &dm816x_usb_phy_pm_ops,
 275                 .of_match_table = of_match_ptr(dm816x_usb_phy_id_table),
 276         },
 277 };
 278
 279 module_platform_driver(dm816x_usb_phy_driver);
 280
 281 MODULE_ALIAS("platform:dm816x_usb");
 282 MODULE_AUTHOR("Tony Lindgren <[email protected]>");
 283 MODULE_DESCRIPTION("dm816x usb phy driver");
 284 MODULE_LICENSE("GPL v2");