drivers/clk/ti/autoidle.c

   1 /*
   2  * TI clock autoidle support
   3  *
   4  * Copyright (C) 2013 Texas Instruments, Inc.
   5  *
   6  * Tero Kristo <t-kristo@ti.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 version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  13  * kind, whether express or implied; without even the implied warranty
  14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/clk-provider.h>
  19 #include <linux/slab.h>
  20 #include <linux/io.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23 #include <linux/clk/ti.h>
  24
  25 struct clk_ti_autoidle {
  26         void __iomem            *reg;
  27         u8                      shift;
  28         u8                      flags;
  29         const char              *name;
  30         struct list_head        node;
  31 };
  32
  33 #define AUTOIDLE_LOW            0x1
  34
  35 static LIST_HEAD(autoidle_clks);
  36
  37 static void ti_allow_autoidle(struct clk_ti_autoidle *clk)
  38 {
  39         u32 val;
  40
  41         val = ti_clk_ll_ops->clk_readl(clk->reg);
  42
  43         if (clk->flags & AUTOIDLE_LOW)
  44                 val &= ~(1 << clk->shift);
  45         else
  46                 val |= (1 << clk->shift);
  47
  48         ti_clk_ll_ops->clk_writel(val, clk->reg);
  49 }
  50
  51 static void ti_deny_autoidle(struct clk_ti_autoidle *clk)
  52 {
  53         u32 val;
  54
  55         val = ti_clk_ll_ops->clk_readl(clk->reg);
  56
  57         if (clk->flags & AUTOIDLE_LOW)
  58                 val |= (1 << clk->shift);
  59         else
  60                 val &= ~(1 << clk->shift);
  61
  62         ti_clk_ll_ops->clk_writel(val, clk->reg);
  63 }
  64
  65 /**
  66  * of_ti_clk_allow_autoidle_all - enable autoidle for all clocks
  67  *
  68  * Enables hardware autoidle for all registered DT clocks, which have
  69  * the feature.
  70  */
  71 void of_ti_clk_allow_autoidle_all(void)
  72 {
  73         struct clk_ti_autoidle *c;
  74
  75         list_for_each_entry(c, &autoidle_clks, node)
  76                 ti_allow_autoidle(c);
  77 }
  78
  79 /**
  80  * of_ti_clk_deny_autoidle_all - disable autoidle for all clocks
  81  *
  82  * Disables hardware autoidle for all registered DT clocks, which have
  83  * the feature.
  84  */
  85 void of_ti_clk_deny_autoidle_all(void)
  86 {
  87         struct clk_ti_autoidle *c;
  88
  89         list_for_each_entry(c, &autoidle_clks, node)
  90                 ti_deny_autoidle(c);
  91 }
  92
  93 /**
  94  * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock
  95  * @node: pointer to the clock device node
  96  *
  97  * Checks if a clock has hardware autoidle support or not (check
  98  * for presence of 'ti,autoidle-shift' property in the device tree
  99  * node) and sets up the hardware autoidle feature for the clock
 100  * if available. If autoidle is available, the clock is also added
 101  * to the autoidle list for later processing. Returns 0 on success,
 102  * negative error value on failure.
 103  */
 104 int __init of_ti_clk_autoidle_setup(struct device_node *node)
 105 {
 106         u32 shift;
 107         struct clk_ti_autoidle *clk;
 108
 109         /* Check if this clock has autoidle support or not */
 110         if (of_property_read_u32(node, "ti,autoidle-shift", &shift))
 111                 return 0;
 112
 113         clk = kzalloc(sizeof(*clk), GFP_KERNEL);
 114
 115         if (!clk)
 116                 return -ENOMEM;
 117
 118         clk->shift = shift;
 119         clk->name = node->name;
 120         clk->reg = ti_clk_get_reg_addr(node, 0);
 121
 122         if (!clk->reg) {
 123                 kfree(clk);
 124                 return -EINVAL;
 125         }
 126
 127         if (of_property_read_bool(node, "ti,invert-autoidle-bit"))
 128                 clk->flags |= AUTOIDLE_LOW;
 129
 130         list_add(&clk->node, &autoidle_clks);
 131
 132         return 0;
 133 }