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/mfd/syscon.h>
  13 #include <linux/module.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/phy/phy.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/regmap.h>
  19 #include <linux/slab.h>
  20
  21 struct bcm_ns_usb2 {
  22         struct device *dev;
  23         struct clk *ref_clk;
  24         struct phy *phy;
  25         struct regmap *clkset;
  26         void __iomem *base;
  27 };
  28
  29 static int bcm_ns_usb2_phy_init(struct phy *phy)
  30 {
  31         struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
  32         struct device *dev = usb2->dev;
  33         u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
  34         int err = 0;
  35
  36         err = clk_prepare_enable(usb2->ref_clk);
  37         if (err < 0) {
  38                 dev_err(dev, "Failed to prepare ref clock: %d\n", err);
  39                 goto err_out;
  40         }
  41
  42         ref_clk_rate = clk_get_rate(usb2->ref_clk);
  43         if (!ref_clk_rate) {
  44                 dev_err(dev, "Failed to get ref clock rate\n");
  45                 err = -EINVAL;
  46                 goto err_clk_off;
  47         }
  48
  49         usb2ctl = readl(usb2->base);
  50
  51         if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
  52                 usb_pll_pdiv = usb2ctl;
  53                 usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
  54                 usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
  55         } else {
  56                 usb_pll_pdiv = 1 << 3;
  57         }
  58
  59         /* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
  60         usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
  61
  62         /* Unlock DMU PLL settings with some magic value */
  63         regmap_write(usb2->clkset, 0, 0x0000ea68);
  64
  65         /* Write USB 2.0 PLL control setting */
  66         usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
  67         usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
  68
  69         writel(usb2ctl, usb2->base);
  70
  71         /* Lock DMU PLL settings */
  72         regmap_write(usb2->clkset, 0, 0x00000000);
  73
  74 err_clk_off:
  75         clk_disable_unprepare(usb2->ref_clk);
  76 err_out:
  77         return err;
  78 }
  79
  80 static const struct phy_ops ops = {
  81         .init           = bcm_ns_usb2_phy_init,
  82         .owner          = THIS_MODULE,
  83 };
  84
  85 static int bcm_ns_usb2_probe(struct platform_device *pdev)
  86 {
  87         struct device *dev = &pdev->dev;
  88         struct bcm_ns_usb2 *usb2;
  89         struct phy_provider *phy_provider;
  90
  91         usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
  92         if (!usb2)
  93                 return -ENOMEM;
  94         usb2->dev = dev;
  95
  96         usb2->base = devm_platform_ioremap_resource(pdev, 0);
  97         if (IS_ERR(usb2->base)) {
  98                 dev_err(dev, "Failed to map control reg\n");
  99                 return PTR_ERR(usb2->base);
 100         }
 101
 102         usb2->clkset = syscon_regmap_lookup_by_phandle(dev->of_node,
 103                                                        "brcm,syscon-clkset");
 104         if (IS_ERR(usb2->clkset)) {
 105                 dev_err(dev, "Failed to lookup clkset regmap\n");
 106                 return PTR_ERR(usb2->clkset);
 107         }
 108
 109         usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
 110         if (IS_ERR(usb2->ref_clk)) {
 111                 dev_err_probe(dev, PTR_ERR(usb2->ref_clk), "failed to get ref clk\n");
 112                 return PTR_ERR(usb2->ref_clk);
 113         }
 114
 115         usb2->phy = devm_phy_create(dev, NULL, &ops);
 116         if (IS_ERR(usb2->phy))
 117                 return PTR_ERR(usb2->phy);
 118
 119         phy_set_drvdata(usb2->phy, usb2);
 120         platform_set_drvdata(pdev, usb2);
 121
 122         phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 123         return PTR_ERR_OR_ZERO(phy_provider);
 124 }
 125
 126 static const struct of_device_id bcm_ns_usb2_id_table[] = {
 127         { .compatible = "brcm,ns-usb2-phy", },
 128         {},
 129 };
 130 MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
 131
 132 static struct platform_driver bcm_ns_usb2_driver = {
 133         .probe          = bcm_ns_usb2_probe,
 134         .driver = {
 135                 .name = "bcm_ns_usb2",
 136                 .of_match_table = bcm_ns_usb2_id_table,
 137         },
 138 };
 139 module_platform_driver(bcm_ns_usb2_driver);
 140
 141 MODULE_DESCRIPTION("Broadcom Northstar USB 2.0 PHY Driver");
 142 MODULE_LICENSE("GPL v2");