drivers/clk/at91/clk-h32mx.c

   1 /*
   2  * clk-h32mx.c
   3  *
   4  *  Copyright (C) 2014 Atmel
   5  *
   6  * Alexandre Belloni <alexandre.belloni@free-electrons.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  */
  14
  15 #include <linux/clk-provider.h>
  16 #include <linux/clkdev.h>
  17 #include <linux/clk/at91_pmc.h>
  18 #include <linux/delay.h>
  19 #include <linux/of.h>
  20 #include <linux/of_address.h>
  21 #include <linux/of_irq.h>
  22 #include <linux/io.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/irq.h>
  25 #include <linux/sched.h>
  26 #include <linux/wait.h>
  27
  28 #include "pmc.h"
  29
  30 #define H32MX_MAX_FREQ  90000000
  31
  32 struct clk_sama5d4_h32mx {
  33         struct clk_hw hw;
  34         struct at91_pmc *pmc;
  35 };
  36
  37 #define to_clk_sama5d4_h32mx(hw) container_of(hw, struct clk_sama5d4_h32mx, hw)
  38
  39 static unsigned long clk_sama5d4_h32mx_recalc_rate(struct clk_hw *hw,
  40                                                  unsigned long parent_rate)
  41 {
  42         struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw);
  43
  44         if (pmc_read(h32mxclk->pmc, AT91_PMC_MCKR) & AT91_PMC_H32MXDIV)
  45                 return parent_rate / 2;
  46
  47         if (parent_rate > H32MX_MAX_FREQ)
  48                 pr_warn("H32MX clock is too fast\n");
  49         return parent_rate;
  50 }
  51
  52 static long clk_sama5d4_h32mx_round_rate(struct clk_hw *hw, unsigned long rate,
  53                                        unsigned long *parent_rate)
  54 {
  55         unsigned long div;
  56
  57         if (rate > *parent_rate)
  58                 return *parent_rate;
  59         div = *parent_rate / 2;
  60         if (rate < div)
  61                 return div;
  62
  63         if (rate - div < *parent_rate - rate)
  64                 return div;
  65
  66         return *parent_rate;
  67 }
  68
  69 static int clk_sama5d4_h32mx_set_rate(struct clk_hw *hw, unsigned long rate,
  70                                     unsigned long parent_rate)
  71 {
  72         struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw);
  73         struct at91_pmc *pmc = h32mxclk->pmc;
  74         u32 tmp;
  75
  76         if (parent_rate != rate && (parent_rate / 2) != rate)
  77                 return -EINVAL;
  78
  79         pmc_lock(pmc);
  80         tmp = pmc_read(pmc, AT91_PMC_MCKR) & ~AT91_PMC_H32MXDIV;
  81         if ((parent_rate / 2) == rate)
  82                 tmp |= AT91_PMC_H32MXDIV;
  83         pmc_write(pmc, AT91_PMC_MCKR, tmp);
  84         pmc_unlock(pmc);
  85
  86         return 0;
  87 }
  88
  89 static const struct clk_ops h32mx_ops = {
  90         .recalc_rate = clk_sama5d4_h32mx_recalc_rate,
  91         .round_rate = clk_sama5d4_h32mx_round_rate,
  92         .set_rate = clk_sama5d4_h32mx_set_rate,
  93 };
  94
  95 void __init of_sama5d4_clk_h32mx_setup(struct device_node *np,
  96                                      struct at91_pmc *pmc)
  97 {
  98         struct clk_sama5d4_h32mx *h32mxclk;
  99         struct clk_init_data init;
 100         const char *parent_name;
 101         struct clk *clk;
 102
 103         h32mxclk = kzalloc(sizeof(*h32mxclk), GFP_KERNEL);
 104         if (!h32mxclk)
 105                 return;
 106
 107         parent_name = of_clk_get_parent_name(np, 0);
 108
 109         init.name = np->name;
 110         init.ops = &h32mx_ops;
 111         init.parent_names = parent_name ? &parent_name : NULL;
 112         init.num_parents = parent_name ? 1 : 0;
 113         init.flags = CLK_SET_RATE_GATE;
 114
 115         h32mxclk->hw.init = &init;
 116         h32mxclk->pmc = pmc;
 117
 118         clk = clk_register(NULL, &h32mxclk->hw);
 119         if (!clk) {
 120                 kfree(h32mxclk);
 121                 return;
 122         }
 123
 124         of_clk_add_provider(np, of_clk_src_simple_get, clk);
 125 }