drivers/clk/at91/clk-usb.c

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