drivers/phy/phy-lpc18xx-usb-otg.c

   1 /*
   2  * PHY driver for NXP LPC18xx/43xx internal USB OTG PHY
   3  *
   4  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/err.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/phy/phy.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/regmap.h>
  20
  21 /* USB OTG PHY register offset and bit in CREG */
  22 #define LPC18XX_CREG_CREG0              0x004
  23 #define LPC18XX_CREG_CREG0_USB0PHY      BIT(5)
  24
  25 struct lpc18xx_usb_otg_phy {
  26         struct phy *phy;
  27         struct clk *clk;
  28         struct regmap *reg;
  29 };
  30
  31 static int lpc18xx_usb_otg_phy_init(struct phy *phy)
  32 {
  33         struct lpc18xx_usb_otg_phy *lpc = phy_get_drvdata(phy);
  34         int ret;
  35
  36         /* The PHY must be clocked at 480 MHz */
  37         ret = clk_set_rate(lpc->clk, 480000000);
  38         if (ret)
  39                 return ret;
  40
  41         return clk_prepare(lpc->clk);
  42 }
  43
  44 static int lpc18xx_usb_otg_phy_exit(struct phy *phy)
  45 {
  46         struct lpc18xx_usb_otg_phy *lpc = phy_get_drvdata(phy);
  47
  48         clk_unprepare(lpc->clk);
  49
  50         return 0;
  51 }
  52
  53 static int lpc18xx_usb_otg_phy_power_on(struct phy *phy)
  54 {
  55         struct lpc18xx_usb_otg_phy *lpc = phy_get_drvdata(phy);
  56         int ret;
  57
  58         ret = clk_enable(lpc->clk);
  59         if (ret)
  60                 return ret;
  61
  62         /* The bit in CREG is cleared to enable the PHY */
  63         ret = regmap_update_bits(lpc->reg, LPC18XX_CREG_CREG0,
  64                                   LPC18XX_CREG_CREG0_USB0PHY, 0);
  65         if (ret) {
  66                 clk_disable(lpc->clk);
  67                 return ret;
  68         }
  69
  70         return 0;
  71 }
  72
  73 static int lpc18xx_usb_otg_phy_power_off(struct phy *phy)
  74 {
  75         struct lpc18xx_usb_otg_phy *lpc = phy_get_drvdata(phy);
  76         int ret;
  77
  78         ret = regmap_update_bits(lpc->reg, LPC18XX_CREG_CREG0,
  79                                  LPC18XX_CREG_CREG0_USB0PHY,
  80                                  LPC18XX_CREG_CREG0_USB0PHY);
  81         if (ret)
  82                 return ret;
  83
  84         clk_disable(lpc->clk);
  85
  86         return 0;
  87 }
  88
  89 static const struct phy_ops lpc18xx_usb_otg_phy_ops = {
  90         .init           = lpc18xx_usb_otg_phy_init,
  91         .exit           = lpc18xx_usb_otg_phy_exit,
  92         .power_on       = lpc18xx_usb_otg_phy_power_on,
  93         .power_off      = lpc18xx_usb_otg_phy_power_off,
  94         .owner          = THIS_MODULE,
  95 };
  96
  97 static int lpc18xx_usb_otg_phy_probe(struct platform_device *pdev)
  98 {
  99         struct phy_provider *phy_provider;
 100         struct lpc18xx_usb_otg_phy *lpc;
 101
 102         lpc = devm_kzalloc(&pdev->dev, sizeof(*lpc), GFP_KERNEL);
 103         if (!lpc)
 104                 return -ENOMEM;
 105
 106         lpc->reg = syscon_node_to_regmap(pdev->dev.of_node->parent);
 107         if (IS_ERR(lpc->reg)) {
 108                 dev_err(&pdev->dev, "failed to get syscon\n");
 109                 return PTR_ERR(lpc->reg);
 110         }
 111
 112         lpc->clk = devm_clk_get(&pdev->dev, NULL);
 113         if (IS_ERR(lpc->clk)) {
 114                 dev_err(&pdev->dev, "failed to get clock\n");
 115                 return PTR_ERR(lpc->clk);
 116         }
 117
 118         lpc->phy = devm_phy_create(&pdev->dev, NULL, &lpc18xx_usb_otg_phy_ops);
 119         if (IS_ERR(lpc->phy)) {
 120                 dev_err(&pdev->dev, "failed to create PHY\n");
 121                 return PTR_ERR(lpc->phy);
 122         }
 123
 124         phy_set_drvdata(lpc->phy, lpc);
 125
 126         phy_provider = devm_of_phy_provider_register(&pdev->dev,
 127                                                      of_phy_simple_xlate);
 128
 129         return PTR_ERR_OR_ZERO(phy_provider);
 130 }
 131
 132 static const struct of_device_id lpc18xx_usb_otg_phy_match[] = {
 133         { .compatible = "nxp,lpc1850-usb-otg-phy" },
 134         { }
 135 };
 136 MODULE_DEVICE_TABLE(of, lpc18xx_usb_otg_phy_match);
 137
 138 static struct platform_driver lpc18xx_usb_otg_phy_driver = {
 139         .probe          = lpc18xx_usb_otg_phy_probe,
 140         .driver         = {
 141                 .name   = "lpc18xx-usb-otg-phy",
 142                 .of_match_table = lpc18xx_usb_otg_phy_match,
 143         },
 144 };
 145 module_platform_driver(lpc18xx_usb_otg_phy_driver);
 146
 147 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 148 MODULE_DESCRIPTION("NXP LPC18xx/43xx USB OTG PHY driver");
 149 MODULE_LICENSE("GPL v2");