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

   1 /*
   2  * Broadcom Northstar USB 2.0 PHY Driver
   3  *
   4  * Copyright (C) 2016 Rafał Miłecki <zajec5@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/bcma/bcma.h>
  13 #include <linux/clk.h>
  14 #include <linux/delay.h>
  15 #include <linux/err.h>
  16 #include <linux/module.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_platform.h>
  19 #include <linux/phy/phy.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22
  23 struct bcm_ns_usb2 {
  24         struct device *dev;
  25         struct clk *ref_clk;
  26         struct phy *phy;
  27         void __iomem *dmu;
  28 };
  29
  30 static int bcm_ns_usb2_phy_init(struct phy *phy)
  31 {
  32         struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
  33         struct device *dev = usb2->dev;
  34         void __iomem *dmu = usb2->dmu;
  35         u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
  36         int err = 0;
  37
  38         err = clk_prepare_enable(usb2->ref_clk);
  39         if (err < 0) {
  40                 dev_err(dev, "Failed to prepare ref clock: %d\n", err);
  41                 goto err_out;
  42         }
  43
  44         ref_clk_rate = clk_get_rate(usb2->ref_clk);
  45         if (!ref_clk_rate) {
  46                 dev_err(dev, "Failed to get ref clock rate\n");
  47                 err = -EINVAL;
  48                 goto err_clk_off;
  49         }
  50
  51         usb2ctl = readl(dmu + BCMA_DMU_CRU_USB2_CONTROL);
  52
  53         if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
  54                 usb_pll_pdiv = usb2ctl;
  55                 usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
  56                 usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
  57         } else {
  58                 usb_pll_pdiv = 1 << 3;
  59         }
  60
  61         /* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
  62         usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;
  63
  64         /* Unlock DMU PLL settings with some magic value */
  65         writel(0x0000ea68, dmu + BCMA_DMU_CRU_CLKSET_KEY);
  66
  67         /* Write USB 2.0 PLL control setting */
  68         usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
  69         usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;
  70         writel(usb2ctl, dmu + BCMA_DMU_CRU_USB2_CONTROL);
  71
  72         /* Lock DMU PLL settings */
  73         writel(0x00000000, dmu + BCMA_DMU_CRU_CLKSET_KEY);
  74
  75 err_clk_off:
  76         clk_disable_unprepare(usb2->ref_clk);
  77 err_out:
  78         return err;
  79 }
  80
  81 static const struct phy_ops ops = {
  82         .init           = bcm_ns_usb2_phy_init,
  83         .owner          = THIS_MODULE,
  84 };
  85
  86 static int bcm_ns_usb2_probe(struct platform_device *pdev)
  87 {
  88         struct device *dev = &pdev->dev;
  89         struct bcm_ns_usb2 *usb2;
  90         struct resource *res;
  91         struct phy_provider *phy_provider;
  92
  93         usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
  94         if (!usb2)
  95                 return -ENOMEM;
  96         usb2->dev = dev;
  97
  98         res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmu");
  99         usb2->dmu = devm_ioremap_resource(dev, res);
 100         if (IS_ERR(usb2->dmu)) {
 101                 dev_err(dev, "Failed to map DMU regs\n");
 102                 return PTR_ERR(usb2->dmu);
 103         }
 104
 105         usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
 106         if (IS_ERR(usb2->ref_clk)) {
 107                 dev_err(dev, "Clock not defined\n");
 108                 return PTR_ERR(usb2->ref_clk);
 109         }
 110
 111         usb2->phy = devm_phy_create(dev, NULL, &ops);
 112         if (IS_ERR(usb2->phy))
 113                 return PTR_ERR(usb2->phy);
 114
 115         phy_set_drvdata(usb2->phy, usb2);
 116         platform_set_drvdata(pdev, usb2);
 117
 118         phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 119         return PTR_ERR_OR_ZERO(phy_provider);
 120 }
 121
 122 static const struct of_device_id bcm_ns_usb2_id_table[] = {
 123         { .compatible = "brcm,ns-usb2-phy", },
 124         {},
 125 };
 126 MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
 127
 128 static struct platform_driver bcm_ns_usb2_driver = {
 129         .probe          = bcm_ns_usb2_probe,
 130         .driver = {
 131                 .name = "bcm_ns_usb2",
 132                 .of_match_table = bcm_ns_usb2_id_table,
 133         },
 134 };
 135 module_platform_driver(bcm_ns_usb2_driver);
 136
 137 MODULE_LICENSE("GPL v2");