drivers/clk/clk_vexpress_osc.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2018 Arm Ltd
   4  * Author: Liviu Dudau <liviu.dudau@foss.arm.com>
   5  *
   6  */
   7 #define DEBUG
   8 #include <common.h>
   9 #include <clk-uclass.h>
  10 #include <dm.h>
  11 #include <dm/device_compat.h>
  12 #include <dm/lists.h>
  13 #include <errno.h>
  14 #include <misc.h>
  15
  16 #define CLK_FUNCTION            BIT(20)
  17
  18 struct vexpress_osc_clk_priv {
  19         u8 osc;
  20         ulong rate_min;
  21         ulong rate_max;
  22 };
  23
  24 static ulong vexpress_osc_clk_get_rate(struct clk *clk)
  25 {
  26         int err;
  27         u32 data;
  28         struct udevice *vexpress_cfg = dev_get_parent(clk->dev);
  29         struct vexpress_osc_clk_priv *priv = dev_get_priv(clk->dev);
  30
  31         data = CLK_FUNCTION | priv->osc;
  32         err = misc_read(vexpress_cfg, 0, &data, sizeof(data));
  33         if (err < 0)
  34                 return err;
  35
  36         return data;
  37 }
  38
  39 #ifndef CONFIG_SPL_BUILD
  40 static ulong vexpress_osc_clk_set_rate(struct clk *clk, ulong rate)
  41 {
  42         int err;
  43         u32 buffer[2];
  44         struct udevice *vexpress_cfg = dev_get_parent(clk->dev);
  45         struct vexpress_osc_clk_priv *priv = dev_get_priv(clk->dev);
  46
  47         if (rate < priv->rate_min || rate > priv->rate_max)
  48                 return -EINVAL;
  49
  50         /*
  51          * we are sending the parent the info about the oscillator
  52          * and the value we want to set
  53          */
  54         buffer[0] = CLK_FUNCTION | priv->osc;
  55         buffer[1] = rate;
  56         err = misc_write(vexpress_cfg, 0, buffer, 2 * sizeof(u32));
  57         if (err < 0)
  58                 return err;
  59
  60         return rate;
  61 }
  62 #endif
  63
  64 static struct clk_ops vexpress_osc_clk_ops = {
  65         .get_rate = vexpress_osc_clk_get_rate,
  66 #ifndef CONFIG_SPL_BUILD
  67         .set_rate = vexpress_osc_clk_set_rate,
  68 #endif
  69 };
  70
  71 static int vexpress_osc_clk_probe(struct udevice *dev)
  72 {
  73         struct vexpress_osc_clk_priv *priv = dev_get_priv(dev);
  74         u32 values[2];
  75         int err;
  76
  77         err = dev_read_u32_array(dev, "freq-range", values, 2);
  78         if (err)
  79                 return err;
  80         priv->rate_min = values[0];
  81         priv->rate_max = values[1];
  82
  83         err = dev_read_u32_array(dev, "arm,vexpress-sysreg,func", values, 2);
  84         if (err)
  85                 return err;
  86
  87         if (values[0] != 1) {
  88                 dev_err(dev, "Invalid VExpress function for clock, must be '1'");
  89                 return -EINVAL;
  90         }
  91         priv->osc = values[1];
  92         debug("clk \"%s%d\", min freq %luHz, max freq %luHz\n", dev->name,
  93               priv->osc, priv->rate_min, priv->rate_max);
  94
  95         return 0;
  96 }
  97
  98 static const struct udevice_id vexpress_osc_clk_ids[] = {
  99         { .compatible = "arm,vexpress-osc", },
 100         {}
 101 };
 102
 103 U_BOOT_DRIVER(vexpress_osc_clk) = {
 104         .name = "vexpress_osc_clk",
 105         .id = UCLASS_CLK,
 106         .of_match = vexpress_osc_clk_ids,
 107         .ops = &vexpress_osc_clk_ops,
 108         .priv_auto_alloc_size = sizeof(struct vexpress_osc_clk_priv),
 109         .probe = vexpress_osc_clk_probe,
 110 };