drivers/clk/tegra/clk-super.c

   1 /*
   2  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/io.h>
  19 #include <linux/delay.h>
  20 #include <linux/err.h>
  21 #include <linux/slab.h>
  22 #include <linux/clk-provider.h>
  23
  24 #include "clk.h"
  25
  26 #define SUPER_STATE_IDLE 0
  27 #define SUPER_STATE_RUN 1
  28 #define SUPER_STATE_IRQ 2
  29 #define SUPER_STATE_FIQ 3
  30
  31 #define SUPER_STATE_SHIFT 28
  32 #define SUPER_STATE_MASK ((BIT(SUPER_STATE_IDLE) | BIT(SUPER_STATE_RUN) | \
  33                            BIT(SUPER_STATE_IRQ) | BIT(SUPER_STATE_FIQ)) \
  34                           << SUPER_STATE_SHIFT)
  35
  36 #define SUPER_LP_DIV2_BYPASS (1 << 16)
  37
  38 #define super_state(s) (BIT(s) << SUPER_STATE_SHIFT)
  39 #define super_state_to_src_shift(m, s) ((m->width * s))
  40 #define super_state_to_src_mask(m) (((1 << m->width) - 1))
  41
  42 static u8 clk_super_get_parent(struct clk_hw *hw)
  43 {
  44         struct tegra_clk_super_mux *mux = to_clk_super_mux(hw);
  45         u32 val, state;
  46         u8 source, shift;
  47
  48         val = readl_relaxed(mux->reg);
  49
  50         state = val & SUPER_STATE_MASK;
  51
  52         BUG_ON((state != super_state(SUPER_STATE_RUN)) &&
  53                (state != super_state(SUPER_STATE_IDLE)));
  54         shift = (state == super_state(SUPER_STATE_IDLE)) ?
  55                 super_state_to_src_shift(mux, SUPER_STATE_IDLE) :
  56                 super_state_to_src_shift(mux, SUPER_STATE_RUN);
  57
  58         source = (val >> shift) & super_state_to_src_mask(mux);
  59
  60         /*
  61          * If LP_DIV2_BYPASS is not set and PLLX is current parent then
  62          * PLLX/2 is the input source to CCLKLP.
  63          */
  64         if ((mux->flags & TEGRA_DIVIDER_2) && !(val & SUPER_LP_DIV2_BYPASS) &&
  65             (source == mux->pllx_index))
  66                 source = mux->div2_index;
  67
  68         return source;
  69 }
  70
  71 static int clk_super_set_parent(struct clk_hw *hw, u8 index)
  72 {
  73         struct tegra_clk_super_mux *mux = to_clk_super_mux(hw);
  74         u32 val, state;
  75         int err = 0;
  76         u8 parent_index, shift;
  77         unsigned long flags = 0;
  78
  79         if (mux->lock)
  80                 spin_lock_irqsave(mux->lock, flags);
  81
  82         val = readl_relaxed(mux->reg);
  83         state = val & SUPER_STATE_MASK;
  84         BUG_ON((state != super_state(SUPER_STATE_RUN)) &&
  85                (state != super_state(SUPER_STATE_IDLE)));
  86         shift = (state == super_state(SUPER_STATE_IDLE)) ?
  87                 super_state_to_src_shift(mux, SUPER_STATE_IDLE) :
  88                 super_state_to_src_shift(mux, SUPER_STATE_RUN);
  89
  90         /*
  91          * For LP mode super-clock switch between PLLX direct
  92          * and divided-by-2 outputs is allowed only when other
  93          * than PLLX clock source is current parent.
  94          */
  95         if ((mux->flags & TEGRA_DIVIDER_2) && ((index == mux->div2_index) ||
  96                                                (index == mux->pllx_index))) {
  97                 parent_index = clk_super_get_parent(hw);
  98                 if ((parent_index == mux->div2_index) ||
  99                     (parent_index == mux->pllx_index)) {
 100                         err = -EINVAL;
 101                         goto out;
 102                 }
 103
 104                 val ^= SUPER_LP_DIV2_BYPASS;
 105                 writel_relaxed(val, mux->reg);
 106                 udelay(2);
 107
 108                 if (index == mux->div2_index)
 109                         index = mux->pllx_index;
 110         }
 111         val &= ~((super_state_to_src_mask(mux)) << shift);
 112         val |= (index & (super_state_to_src_mask(mux))) << shift;
 113
 114         writel_relaxed(val, mux->reg);
 115         udelay(2);
 116
 117 out:
 118         if (mux->lock)
 119                 spin_unlock_irqrestore(mux->lock, flags);
 120
 121         return err;
 122 }
 123
 124 const struct clk_ops tegra_clk_super_ops = {
 125         .get_parent = clk_super_get_parent,
 126         .set_parent = clk_super_set_parent,
 127 };
 128
 129 struct clk *tegra_clk_register_super_mux(const char *name,
 130                 const char **parent_names, u8 num_parents,
 131                 unsigned long flags, void __iomem *reg, u8 clk_super_flags,
 132                 u8 width, u8 pllx_index, u8 div2_index, spinlock_t *lock)
 133 {
 134         struct tegra_clk_super_mux *super;
 135         struct clk *clk;
 136         struct clk_init_data init;
 137
 138         super = kzalloc(sizeof(*super), GFP_KERNEL);
 139         if (!super) {
 140                 pr_err("%s: could not allocate super clk\n", __func__);
 141                 return ERR_PTR(-ENOMEM);
 142         }
 143
 144         init.name = name;
 145         init.ops = &tegra_clk_super_ops;
 146         init.flags = flags;
 147         init.parent_names = parent_names;
 148         init.num_parents = num_parents;
 149
 150         super->reg = reg;
 151         super->pllx_index = pllx_index;
 152         super->div2_index = div2_index;
 153         super->lock = lock;
 154         super->width = width;
 155         super->flags = clk_super_flags;
 156
 157         /* Data in .init is copied by clk_register(), so stack variable OK */
 158         super->hw.init = &init;
 159
 160         clk = clk_register(NULL, &super->hw);
 161         if (IS_ERR(clk))
 162                 kfree(super);
 163
 164         return clk;
 165 }