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