drivers/phy/broadcom/phy-bcm-ns-usb2.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Broadcom Northstar USB 2.0 PHY Driver
   4  *
   5  * Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>
   6  */
   7
   8 #include <linux/bcma/bcma.h>
   9 #include <linux/clk.h>
  10 #include <linux/delay.h>
  11 #include <linux/err.h>
  12 #include <linux/module.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_platform.h>
  15 #include <linux/phy/phy.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/slab.h>
  18
  19 struct bcm_ns_usb2 {
  20         struct device *dev;
  21         struct clk *ref_clk;
  22         struct phy *phy;
  23         void __iomem *dmu;
  24 };
  25
  26 static int bcm_ns_usb2_phy_init(struct phy *phy)
  27 {
  28         struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
  29         struct device *dev = usb2->dev;
  30         void __iomem *dmu = usb2->dmu;
  31         u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
  32         int err = 0;
  33
  34         err = clk_prepare_enable(usb2->ref_clk);
  35         if (err < 0) {
  36                 dev_err(dev, "Failed to prepare ref clock: %d\n", err);
  37                 goto err_out;
  38         }
  39
  40         ref_clk_rate = clk_get_rate(usb2->ref_clk);
  41         if (!ref_clk_rate) {
  42                 dev_err(dev, "Failed to get ref clock rate\n");
  43                 err = -EINVAL;
  44                 goto err_clk_off;
  45         }
  46
  47         usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);
  48
  49         if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
  50                 usb_pll_pdiv = usb2ctl;
  51                 usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
  52                 usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
  53         } else {
  54                 usb_pll_pdiv = 1 << 3;
  55         }
  56
  57         /* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
  58         usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
  59
  60         /* Unlock DMU PLL settings with some magic value */
  61         writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
  62
  63         /* Write USB 2.0 PLL control setting */
  64         usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
  65         usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
  66         writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
  67
  68         /* Lock DMU PLL settings */
  69         writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
  70
  71 err_clk_off:
  72         clk_disable_unprepare(usb2->ref_clk);
  73 err_out:
  74         return err;
  75 }
  76
  77 static const struct phy_ops ops = {
  78         .init           = bcm_ns_usb2_phy_init,
  79         .owner          = THIS_MODULE,
  80 };
  81
  82 static int bcm_ns_usb2_probe(struct platform_device *pdev)
  83 {
  84         struct device *dev = &pdev->dev;
  85         struct bcm_ns_usb2 *usb2;
  86         struct phy_provider *phy_provider;
  87
  88         usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
  89         if (!usb2)
  90                 return -ENOMEM;
  91         usb2->dev = dev;
  92
  93         usb2->dmu = devm_platform_ioremap_resource_byname(pdev, "dmu");
  94         if (IS_ERR(usb2->dmu)) {
  95                 dev_err(dev, "Failed to map DMU regs\n");
  96                 return PTR_ERR(usb2->dmu);
  97         }
  98
  99         usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
 100         if (IS_ERR(usb2->ref_clk)) {
 101                 dev_err(dev, "Clock not defined\n");
 102                 return PTR_ERR(usb2->ref_clk);
 103         }
 104
 105         usb2->phy = devm_phy_create(dev, NULL, &ops);
 106         if (IS_ERR(usb2->phy))
 107                 return PTR_ERR(usb2->phy);
 108
 109         phy_set_drvdata(usb2->phy, usb2);
 110         platform_set_drvdata(pdev, usb2);
 111
 112         phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 113         return PTR_ERR_OR_ZERO(phy_provider);
 114 }
 115
 116 static const struct of_device_id bcm_ns_usb2_id_table[] = {
 117         { .compatible = "brcm,ns-usb2-phy", },
 118         {},
 119 };
 120 MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
 121
 122 static struct platform_driver bcm_ns_usb2_driver = {
 123         .probe          = bcm_ns_usb2_probe,
 124         .driver = {
 125                 .name = "bcm_ns_usb2",
 126                 .of_match_table = bcm_ns_usb2_id_table,
 127         },
 128 };
 129 module_platform_driver(bcm_ns_usb2_driver);
 130
 131 MODULE_LICENSE("GPL v2");