linux/drivers/phy/phy-dm816x-usb.c
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   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
  52struct 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
  62static 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
  71static 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
  81static int dm816x_usb_phy_init(struct phy *x)
  82{
  83        struct dm816x_usb_phy *phy = phy_get_drvdata(x);
  84        unsigned int val;
  85        int error;
  86
  87        if (clk_get_rate(phy->refclk) != 24000000)
  88                dev_warn(phy->dev, "nonstandard phy refclk\n");
  89
  90        /* Set PLL ref clock and put phys to sleep */
  91        error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
  92                                   DM816X_USB_CTRL_PHYCLKSRC |
  93                                   DM816X_USB_CTRL_PHYSLEEP1 |
  94                                   DM816X_USB_CTRL_PHYSLEEP0,
  95                                   0);
  96        regmap_read(phy->syscon, phy->usb_ctrl, &val);
  97        if ((val & 3) != 0)
  98                dev_info(phy->dev,
  99                         "Working dm816x USB_CTRL! (0x%08x)\n",
 100                         val);
 101
 102        /*
 103         * TI kernel sets these values for "symmetrical eye diagram and
 104         * better signal quality" so let's assume somebody checked the
 105         * values with a scope and set them here too.
 106         */
 107        regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
 108        val |= DM816X_USBPHY_CTRL_TXRISETUNE |
 109                DM816X_USBPHY_CTRL_TXVREFTUNE |
 110                DM816X_USBPHY_CTRL_TXPREEMTUNE;
 111        regmap_write(phy->syscon, phy->usbphy_ctrl, val);
 112
 113        return 0;
 114}
 115
 116static struct phy_ops ops = {
 117        .init           = dm816x_usb_phy_init,
 118        .owner          = THIS_MODULE,
 119};
 120
 121static int dm816x_usb_phy_runtime_suspend(struct device *dev)
 122{
 123        struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
 124        unsigned int mask, val;
 125        int error = 0;
 126
 127        mask = BIT(phy->instance);
 128        val = ~BIT(phy->instance);
 129        error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
 130                                   mask, val);
 131        if (error)
 132                dev_err(phy->dev, "phy%i failed to power off\n",
 133                        phy->instance);
 134        clk_disable(phy->refclk);
 135
 136        return 0;
 137}
 138
 139static int dm816x_usb_phy_runtime_resume(struct device *dev)
 140{
 141        struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
 142        unsigned int mask, val;
 143        int error;
 144
 145        error = clk_enable(phy->refclk);
 146        if (error)
 147                return error;
 148
 149        /*
 150         * Note that at least dm816x rev c does not seem to do
 151         * anything with the USB_CTRL register. But let's follow
 152         * what the TI tree is doing in case later revisions use
 153         * USB_CTRL.
 154         */
 155        mask = BIT(phy->instance);
 156        val = BIT(phy->instance);
 157        error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
 158                                   mask, val);
 159        if (error) {
 160                dev_err(phy->dev, "phy%i failed to power on\n",
 161                        phy->instance);
 162                clk_disable(phy->refclk);
 163                return error;
 164        }
 165
 166        return 0;
 167}
 168
 169static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,
 170                            dm816x_usb_phy_runtime_suspend,
 171                            dm816x_usb_phy_runtime_resume,
 172                            NULL);
 173
 174#ifdef CONFIG_OF
 175static const struct of_device_id dm816x_usb_phy_id_table[] = {
 176        {
 177                .compatible = "ti,dm8168-usb-phy",
 178        },
 179        {},
 180};
 181MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
 182#endif
 183
 184static int dm816x_usb_phy_probe(struct platform_device *pdev)
 185{
 186        struct dm816x_usb_phy *phy;
 187        struct resource *res;
 188        struct phy *generic_phy;
 189        struct phy_provider *phy_provider;
 190        struct usb_otg *otg;
 191        const struct of_device_id *of_id;
 192        const struct usb_phy_data *phy_data;
 193        int error;
 194
 195        of_id = of_match_device(of_match_ptr(dm816x_usb_phy_id_table),
 196                                &pdev->dev);
 197        if (!of_id)
 198                return -EINVAL;
 199
 200        phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
 201        if (!phy)
 202                return -ENOMEM;
 203
 204        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 205        if (!res)
 206                return -ENOENT;
 207
 208        phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
 209                                                      "syscon");
 210        if (IS_ERR(phy->syscon))
 211                return PTR_ERR(phy->syscon);
 212
 213        /*
 214         * According to sprs614e.pdf, the first usb_ctrl is shared and
 215         * the second instance for usb_ctrl is reserved.. Also the
 216         * register bits are different from earlier TRMs.
 217         */
 218        phy->usb_ctrl = 0x20;
 219        phy->usbphy_ctrl = (res->start & 0xff) + 4;
 220        if (phy->usbphy_ctrl == 0x2c)
 221                phy->instance = 1;
 222
 223        phy_data = of_id->data;
 224
 225        otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
 226        if (!otg)
 227                return -ENOMEM;
 228
 229        phy->dev = &pdev->dev;
 230        phy->phy.dev = phy->dev;
 231        phy->phy.label = "dm8168_usb_phy";
 232        phy->phy.otg = otg;
 233        phy->phy.type = USB_PHY_TYPE_USB2;
 234        otg->set_host = dm816x_usb_phy_set_host;
 235        otg->set_peripheral = dm816x_usb_phy_set_peripheral;
 236        otg->usb_phy = &phy->phy;
 237
 238        platform_set_drvdata(pdev, phy);
 239
 240        phy->refclk = devm_clk_get(phy->dev, "refclk");
 241        if (IS_ERR(phy->refclk))
 242                return PTR_ERR(phy->refclk);
 243        error = clk_prepare(phy->refclk);
 244        if (error)
 245                return error;
 246
 247        pm_runtime_enable(phy->dev);
 248        generic_phy = devm_phy_create(phy->dev, NULL, &ops);
 249        if (IS_ERR(generic_phy))
 250                return PTR_ERR(generic_phy);
 251
 252        phy_set_drvdata(generic_phy, phy);
 253
 254        phy_provider = devm_of_phy_provider_register(phy->dev,
 255                                                     of_phy_simple_xlate);
 256        if (IS_ERR(phy_provider))
 257                return PTR_ERR(phy_provider);
 258
 259        usb_add_phy_dev(&phy->phy);
 260
 261        return 0;
 262}
 263
 264static int dm816x_usb_phy_remove(struct platform_device *pdev)
 265{
 266        struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);
 267
 268        usb_remove_phy(&phy->phy);
 269        pm_runtime_disable(phy->dev);
 270        clk_unprepare(phy->refclk);
 271
 272        return 0;
 273}
 274
 275static struct platform_driver dm816x_usb_phy_driver = {
 276        .probe          = dm816x_usb_phy_probe,
 277        .remove         = dm816x_usb_phy_remove,
 278        .driver         = {
 279                .name   = "dm816x-usb-phy",
 280                .pm     = &dm816x_usb_phy_pm_ops,
 281                .of_match_table = of_match_ptr(dm816x_usb_phy_id_table),
 282        },
 283};
 284
 285module_platform_driver(dm816x_usb_phy_driver);
 286
 287MODULE_ALIAS("platform:dm816x_usb");
 288MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
 289MODULE_DESCRIPTION("dm816x usb phy driver");
 290MODULE_LICENSE("GPL v2");
 291