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 <log.h>
  10 #include <dm/device.h>
  11 #include <linux/err.h>
  12 #include <linux/io.h>
  13 #include <mach/at91_pmc.h>
  14 #include "pmc.h"
  15
  16 DECLARE_GLOBAL_DATA_PTR;
  17
  18 #define AT91_USB_CLK_SOURCE_MAX 2
  19 #define AT91_USB_CLK_MAX_DIV    15
  20
  21 struct at91_usb_clk_priv {
  22         u32 num_clksource;
  23 };
  24
  25 static ulong at91_usb_clk_get_rate(struct clk *clk)
  26 {
  27         struct pmc_platdata *plat = dev_get_platdata(clk->dev);
  28         struct at91_pmc *pmc = plat->reg_base;
  29         struct clk source;
  30         u32 tmp, usbdiv;
  31         u8 source_index;
  32         int ret;
  33
  34         tmp = readl(&pmc->pcr);
  35         source_index = (tmp >> AT91_PMC_USB_USBS_OFFSET) &
  36                         AT91_PMC_USB_USBS_MASK;
  37         usbdiv = (tmp >> AT91_PMC_USB_DIV_OFFSET) & AT91_PMC_USB_DIV_MASK;
  38
  39         ret = clk_get_by_index(clk->dev, source_index, &source);
  40         if (ret)
  41                 return 0;
  42
  43         return clk_get_rate(&source) / (usbdiv + 1);
  44 }
  45
  46 static ulong at91_usb_clk_set_rate(struct clk *clk, ulong rate)
  47 {
  48         struct pmc_platdata *plat = dev_get_platdata(clk->dev);
  49         struct at91_pmc *pmc = plat->reg_base;
  50         struct at91_usb_clk_priv *priv = dev_get_priv(clk->dev);
  51         struct clk source, best_source;
  52         ulong tmp_rate, best_rate = rate, source_rate;
  53         int tmp_diff, best_diff = -1;
  54         u32 div, best_div = 0;
  55         u8 best_source_index = 0;
  56         u8 i;
  57         u32 tmp;
  58         int ret;
  59
  60         for (i = 0; i < priv->num_clksource; i++) {
  61                 ret = clk_get_by_index(clk->dev, i, &source);
  62                 if (ret)
  63                         return ret;
  64
  65                 source_rate = clk_get_rate(&source);
  66                 if (IS_ERR_VALUE(source_rate))
  67                         return source_rate;
  68
  69                 for (div = 1; div < AT91_USB_CLK_MAX_DIV + 2; div++) {
  70                         tmp_rate = DIV_ROUND_CLOSEST(source_rate, div);
  71                         tmp_diff = abs(rate - tmp_rate);
  72
  73                         if (best_diff < 0 || best_diff > tmp_diff) {
  74                                 best_rate = tmp_rate;
  75                                 best_diff = tmp_diff;
  76
  77                                 best_div = div - 1;
  78                                 best_source = source;
  79                                 best_source_index = i;
  80                         }
  81
  82                         if (!best_diff || tmp_rate < rate)
  83                                 break;
  84                 }
  85
  86                 if (!best_diff)
  87                         break;
  88         }
  89
  90         debug("AT91 USB: best sourc: %s, best_rate = %ld, best_div = %d\n",
  91               best_source.dev->name, best_rate, best_div);
  92
  93         ret = clk_enable(&best_source);
  94         if (ret)
  95                 return ret;
  96
  97         tmp = AT91_PMC_USB_USBS_(best_source_index) |
  98               AT91_PMC_USB_DIV_(best_div);
  99         writel(tmp, &pmc->usb);
 100
 101         return 0;
 102 }
 103
 104 static struct clk_ops at91_usb_clk_ops = {
 105         .get_rate = at91_usb_clk_get_rate,
 106         .set_rate = at91_usb_clk_set_rate,
 107 };
 108
 109 static int at91_usb_clk_ofdata_to_platdata(struct udevice *dev)
 110 {
 111         struct at91_usb_clk_priv *priv = dev_get_priv(dev);
 112         u32 cells[AT91_USB_CLK_SOURCE_MAX];
 113         u32 num_clksource;
 114
 115         num_clksource = fdtdec_get_int_array_count(gd->fdt_blob,
 116                                                    dev_of_offset(dev),
 117                                                    "clocks", cells,
 118                                                    AT91_USB_CLK_SOURCE_MAX);
 119
 120         if (!num_clksource)
 121                 return -1;
 122
 123         priv->num_clksource = num_clksource;
 124
 125         return 0;
 126 }
 127
 128 static int at91_usb_clk_probe(struct udevice *dev)
 129 {
 130         return at91_pmc_core_probe(dev);
 131 }
 132
 133 static const struct udevice_id at91_usb_clk_match[] = {
 134         { .compatible = "atmel,at91sam9x5-clk-usb" },
 135         {}
 136 };
 137
 138 U_BOOT_DRIVER(at91_usb_clk) = {
 139         .name = "at91-usb-clk",
 140         .id = UCLASS_CLK,
 141         .of_match = at91_usb_clk_match,
 142         .probe = at91_usb_clk_probe,
 143         .ofdata_to_platdata = at91_usb_clk_ofdata_to_platdata,
 144         .priv_auto_alloc_size = sizeof(struct at91_usb_clk_priv),
 145         .platdata_auto_alloc_size = sizeof(struct pmc_platdata),
 146         .ops = &at91_usb_clk_ops,
 147 };