drivers/clk/at91/clk-utmi.c

   1 /*
   2  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk/at91_pmc.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <linux/of.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/io.h>
  20 #include <linux/sched.h>
  21 #include <linux/wait.h>
  22
  23 #include "pmc.h"
  24
  25 #define UTMI_FIXED_MUL          40
  26
  27 struct clk_utmi {
  28         struct clk_hw hw;
  29         struct at91_pmc *pmc;
  30         unsigned int irq;
  31         wait_queue_head_t wait;
  32 };
  33
  34 #define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
  35
  36 static irqreturn_t clk_utmi_irq_handler(int irq, void *dev_id)
  37 {
  38         struct clk_utmi *utmi = (struct clk_utmi *)dev_id;
  39
  40         wake_up(&utmi->wait);
  41         disable_irq_nosync(utmi->irq);
  42
  43         return IRQ_HANDLED;
  44 }
  45
  46 static int clk_utmi_prepare(struct clk_hw *hw)
  47 {
  48         struct clk_utmi *utmi = to_clk_utmi(hw);
  49         struct at91_pmc *pmc = utmi->pmc;
  50         u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) | AT91_PMC_UPLLEN |
  51                   AT91_PMC_UPLLCOUNT | AT91_PMC_BIASEN;
  52
  53         pmc_write(pmc, AT91_CKGR_UCKR, tmp);
  54
  55         while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU)) {
  56                 enable_irq(utmi->irq);
  57                 wait_event(utmi->wait,
  58                            pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU);
  59         }
  60
  61         return 0;
  62 }
  63
  64 static int clk_utmi_is_prepared(struct clk_hw *hw)
  65 {
  66         struct clk_utmi *utmi = to_clk_utmi(hw);
  67         struct at91_pmc *pmc = utmi->pmc;
  68
  69         return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU);
  70 }
  71
  72 static void clk_utmi_unprepare(struct clk_hw *hw)
  73 {
  74         struct clk_utmi *utmi = to_clk_utmi(hw);
  75         struct at91_pmc *pmc = utmi->pmc;
  76         u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) & ~AT91_PMC_UPLLEN;
  77
  78         pmc_write(pmc, AT91_CKGR_UCKR, tmp);
  79 }
  80
  81 static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
  82                                           unsigned long parent_rate)
  83 {
  84         /* UTMI clk is a fixed clk multiplier */
  85         return parent_rate * UTMI_FIXED_MUL;
  86 }
  87
  88 static const struct clk_ops utmi_ops = {
  89         .prepare = clk_utmi_prepare,
  90         .unprepare = clk_utmi_unprepare,
  91         .is_prepared = clk_utmi_is_prepared,
  92         .recalc_rate = clk_utmi_recalc_rate,
  93 };
  94
  95 static struct clk * __init
  96 at91_clk_register_utmi(struct at91_pmc *pmc, unsigned int irq,
  97                        const char *name, const char *parent_name)
  98 {
  99         int ret;
 100         struct clk_utmi *utmi;
 101         struct clk *clk = NULL;
 102         struct clk_init_data init;
 103
 104         utmi = kzalloc(sizeof(*utmi), GFP_KERNEL);
 105         if (!utmi)
 106                 return ERR_PTR(-ENOMEM);
 107
 108         init.name = name;
 109         init.ops = &utmi_ops;
 110         init.parent_names = parent_name ? &parent_name : NULL;
 111         init.num_parents = parent_name ? 1 : 0;
 112         init.flags = CLK_SET_RATE_GATE;
 113
 114         utmi->hw.init = &init;
 115         utmi->pmc = pmc;
 116         utmi->irq = irq;
 117         init_waitqueue_head(&utmi->wait);
 118         irq_set_status_flags(utmi->irq, IRQ_NOAUTOEN);
 119         ret = request_irq(utmi->irq, clk_utmi_irq_handler,
 120                           IRQF_TRIGGER_HIGH, "clk-utmi", utmi);
 121         if (ret)
 122                 return ERR_PTR(ret);
 123
 124         clk = clk_register(NULL, &utmi->hw);
 125         if (IS_ERR(clk))
 126                 kfree(utmi);
 127
 128         return clk;
 129 }
 130
 131 static void __init
 132 of_at91_clk_utmi_setup(struct device_node *np, struct at91_pmc *pmc)
 133 {
 134         unsigned int irq;
 135         struct clk *clk;
 136         const char *parent_name;
 137         const char *name = np->name;
 138
 139         parent_name = of_clk_get_parent_name(np, 0);
 140
 141         of_property_read_string(np, "clock-output-names", &name);
 142
 143         irq = irq_of_parse_and_map(np, 0);
 144         if (!irq)
 145                 return;
 146
 147         clk = at91_clk_register_utmi(pmc, irq, name, parent_name);
 148         if (IS_ERR(clk))
 149                 return;
 150
 151         of_clk_add_provider(np, of_clk_src_simple_get, clk);
 152         return;
 153 }
 154
 155 void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np,
 156                                          struct at91_pmc *pmc)
 157 {
 158         of_at91_clk_utmi_setup(np, pmc);
 159 }