drivers/clk/at91/clk-usb.c

   1 /*
   2  * Copyright (C) 2018 Microhip / Atmel Corporation
   3  *               Wenyou.Yang <wenyou.yang@microchip.com>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <clk-uclass.h>
  10 #include <dm/device.h>
  11 #include <linux/io.h>
  12 #include <mach/at91_pmc.h>
  13 #include "pmc.h"
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 #define AT91_USB_CLK_SOURCE_MAX 2
  18 #define AT91_USB_CLK_MAX_DIV    15
  19
  20 struct at91_usb_clk_priv {
  21         u32 num_clksource;
  22 };
  23
  24 static ulong at91_usb_clk_get_rate(struct clk *clk)
  25 {
  26         struct pmc_platdata *plat = dev_get_platdata(clk->dev);
  27         struct at91_pmc *pmc = plat->reg_base;
  28         struct clk source;
  29         u32 tmp, usbdiv;
  30         u8 source_index;
  31         int ret;
  32
  33         tmp = readl(&pmc->pcr);
  34         source_index = (tmp >> AT91_PMC_USB_USBS_OFFSET) &
  35                         AT91_PMC_USB_USBS_MASK;
  36         usbdiv = (tmp >> AT91_PMC_USB_DIV_OFFSET) & AT91_PMC_USB_DIV_MASK;
  37
  38         ret = clk_get_by_index(clk->dev, source_index, &source);
  39         if (ret)
  40                 return 0;
  41
  42         return clk_get_rate(&source) / (usbdiv + 1);
  43 }
  44
  45 static ulong at91_usb_clk_set_rate(struct clk *clk, ulong rate)
  46 {
  47         struct pmc_platdata *plat = dev_get_platdata(clk->dev);
  48         struct at91_pmc *pmc = plat->reg_base;
  49         struct at91_usb_clk_priv *priv = dev_get_priv(clk->dev);
  50         struct clk source, best_source;
  51         ulong tmp_rate, best_rate = rate, source_rate;
  52         int tmp_diff, best_diff = -1;
  53         u32 div, best_div = 0;
  54         u8 best_source_index = 0;
  55         u8 i;
  56         u32 tmp;
  57         int ret;
  58
  59         for (i = 0; i < priv->num_clksource; i++) {
  60                 ret = clk_get_by_index(clk->dev, i, &source);
  61                 if (ret)
  62                         return ret;
  63
  64                 source_rate = clk_get_rate(&source);
  65                 if (IS_ERR_VALUE(source_rate))
  66                         return source_rate;
  67
  68                 for (div = 1; div < AT91_USB_CLK_MAX_DIV + 2; div++) {
  69                         tmp_rate = DIV_ROUND_CLOSEST(source_rate, div);
  70                         tmp_diff = abs(rate - tmp_rate);
  71
  72                         if (best_diff < 0 || best_diff > tmp_diff) {
  73                                 best_rate = tmp_rate;
  74                                 best_diff = tmp_diff;
  75
  76                                 best_div = div - 1;
  77                                 best_source = source;
  78                                 best_source_index = i;
  79                         }
  80
  81                         if (!best_diff || tmp_rate < rate)
  82                                 break;
  83                 }
  84
  85                 if (!best_diff)
  86                         break;
  87         }
  88
  89         debug("AT91 USB: best sourc: %s, best_rate = %ld, best_div = %d\n",
  90               best_source.dev->name, best_rate, best_div);
  91
  92         ret = clk_enable(&best_source);
  93         if (ret)
  94                 return ret;
  95
  96         tmp = AT91_PMC_USB_USBS_(best_source_index) |
  97               AT91_PMC_USB_DIV_(best_div);
  98         writel(tmp, &pmc->usb);
  99
 100         return 0;
 101 }
 102
 103 static struct clk_ops at91_usb_clk_ops = {
 104         .get_rate = at91_usb_clk_get_rate,
 105         .set_rate = at91_usb_clk_set_rate,
 106 };
 107
 108 static int at91_usb_clk_ofdata_to_platdata(struct udevice *dev)
 109 {
 110         struct at91_usb_clk_priv *priv = dev_get_priv(dev);
 111         u32 cells[AT91_USB_CLK_SOURCE_MAX];
 112         u32 num_clksource;
 113
 114         num_clksource = fdtdec_get_int_array_count(gd->fdt_blob,
 115                                                    dev_of_offset(dev),
 116                                                    "clocks", cells,
 117                                                    AT91_USB_CLK_SOURCE_MAX);
 118
 119         if (!num_clksource)
 120                 return -1;
 121
 122         priv->num_clksource = num_clksource;
 123
 124         return 0;
 125 }
 126
 127 static int at91_usb_clk_probe(struct udevice *dev)
 128 {
 129         return at91_pmc_core_probe(dev);
 130 }
 131
 132 static const struct udevice_id at91_usb_clk_match[] = {
 133         { .compatible = "atmel,at91sam9x5-clk-usb" },
 134         {}
 135 };
 136
 137 U_BOOT_DRIVER(at91_usb_clk) = {
 138         .name = "at91-usb-clk",
 139         .id = UCLASS_CLK,
 140         .of_match = at91_usb_clk_match,
 141         .probe = at91_usb_clk_probe,
 142         .ofdata_to_platdata = at91_usb_clk_ofdata_to_platdata,
 143         .priv_auto_alloc_size = sizeof(struct at91_usb_clk_priv),
 144         .platdata_auto_alloc_size = sizeof(struct pmc_platdata),
 145         .ops = &at91_usb_clk_ops,
 146 };