LXR linux/drivers/phy/broadcom/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
  23struct bcm_ns_usb2 {
  24        struct device *dev;
  25        struct clk *ref_clk;
  26        struct phy *phy;
  27        void __iomem *dmu;
  28};
  29
  30static 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
  75err_clk_off:
  76        clk_disable_unprepare(usb2->ref_clk);
  77err_out:
  78        return err;
  79}
  80
  81static const struct phy_ops ops = {
  82        .init           = bcm_ns_usb2_phy_init,
  83        .owner          = THIS_MODULE,
  84};
  85
  86static 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
 122static const struct of_device_id bcm_ns_usb2_id_table[] = {
 123        { .compatible = "brcm,ns-usb2-phy", },
 124        {},
 125};
 126MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);
 127
 128static 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};
 135module_platform_driver(bcm_ns_usb2_driver);
 136
 137MODULE_LICENSE("GPL v2");
 138