drivers/clk/imx/clk-gate-exclusive.c

   1 /*
   2  * Copyright 2014 Freescale Semiconductor, Inc.
   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 version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/err.h>
  11 #include <linux/io.h>
  12 #include <linux/slab.h>
  13 #include "clk.h"
  14
  15 /**
  16  * struct clk_gate_exclusive - i.MX specific gate clock which is mutually
  17  * exclusive with other gate clocks
  18  *
  19  * @gate: the parent class
  20  * @exclusive_mask: mask of gate bits which are mutually exclusive to this
  21  *      gate clock
  22  *
  23  * The imx exclusive gate clock is a subclass of basic clk_gate
  24  * with an addtional mask to indicate which other gate bits in the same
  25  * register is mutually exclusive to this gate clock.
  26  */
  27 struct clk_gate_exclusive {
  28         struct clk_gate gate;
  29         u32 exclusive_mask;
  30 };
  31
  32 static int clk_gate_exclusive_enable(struct clk_hw *hw)
  33 {
  34         struct clk_gate *gate = to_clk_gate(hw);
  35         struct clk_gate_exclusive *exgate = container_of(gate,
  36                                         struct clk_gate_exclusive, gate);
  37         u32 val = readl(gate->reg);
  38
  39         if (val & exgate->exclusive_mask)
  40                 return -EBUSY;
  41
  42         return clk_gate_ops.enable(hw);
  43 }
  44
  45 static void clk_gate_exclusive_disable(struct clk_hw *hw)
  46 {
  47         clk_gate_ops.disable(hw);
  48 }
  49
  50 static int clk_gate_exclusive_is_enabled(struct clk_hw *hw)
  51 {
  52         return clk_gate_ops.is_enabled(hw);
  53 }
  54
  55 static const struct clk_ops clk_gate_exclusive_ops = {
  56         .enable = clk_gate_exclusive_enable,
  57         .disable = clk_gate_exclusive_disable,
  58         .is_enabled = clk_gate_exclusive_is_enabled,
  59 };
  60
  61 struct clk *imx_clk_gate_exclusive(const char *name, const char *parent,
  62          void __iomem *reg, u8 shift, u32 exclusive_mask)
  63 {
  64         struct clk_gate_exclusive *exgate;
  65         struct clk_gate *gate;
  66         struct clk *clk;
  67         struct clk_init_data init;
  68
  69         if (exclusive_mask == 0)
  70                 return ERR_PTR(-EINVAL);
  71
  72         exgate = kzalloc(sizeof(*exgate), GFP_KERNEL);
  73         if (!exgate)
  74                 return ERR_PTR(-ENOMEM);
  75         gate = &exgate->gate;
  76
  77         init.name = name;
  78         init.ops = &clk_gate_exclusive_ops;
  79         init.flags = CLK_SET_RATE_PARENT;
  80         init.parent_names = parent ? &parent : NULL;
  81         init.num_parents = parent ? 1 : 0;
  82
  83         gate->reg = reg;
  84         gate->bit_idx = shift;
  85         gate->lock = &imx_ccm_lock;
  86         gate->hw.init = &init;
  87         exgate->exclusive_mask = exclusive_mask;
  88
  89         clk = clk_register(NULL, &gate->hw);
  90         if (IS_ERR(clk))
  91                 kfree(exgate);
  92
  93         return clk;
  94 }