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

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