drivers/clk/imx/clk-lpcg-scu.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright 2018 NXP
   4  *      Dong Aisheng <aisheng.dong@nxp.com>
   5  */
   6
   7 #include <linux/bits.h>
   8 #include <linux/clk-provider.h>
   9 #include <linux/err.h>
  10 #include <linux/io.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13
  14 #include "clk-scu.h"
  15
  16 static DEFINE_SPINLOCK(imx_lpcg_scu_lock);
  17
  18 #define CLK_GATE_SCU_LPCG_MASK          0x3
  19 #define CLK_GATE_SCU_LPCG_HW_SEL        BIT(0)
  20 #define CLK_GATE_SCU_LPCG_SW_SEL        BIT(1)
  21
  22 /*
  23  * struct clk_lpcg_scu - Description of LPCG clock
  24  *
  25  * @hw: clk_hw of this LPCG
  26  * @reg: register of this LPCG clock
  27  * @bit_idx: bit index of this LPCG clock
  28  * @hw_gate: HW auto gate enable
  29  *
  30  * This structure describes one LPCG clock
  31  */
  32 struct clk_lpcg_scu {
  33         struct clk_hw hw;
  34         void __iomem *reg;
  35         u8 bit_idx;
  36         bool hw_gate;
  37
  38         /* for state save&restore */
  39         u32 state;
  40 };
  41
  42 #define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
  43
  44 static int clk_lpcg_scu_enable(struct clk_hw *hw)
  45 {
  46         struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
  47         unsigned long flags;
  48         u32 reg, val;
  49
  50         spin_lock_irqsave(&imx_lpcg_scu_lock, flags);
  51
  52         reg = readl_relaxed(clk->reg);
  53         reg &= ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx);
  54
  55         val = CLK_GATE_SCU_LPCG_SW_SEL;
  56         if (clk->hw_gate)
  57                 val |= CLK_GATE_SCU_LPCG_HW_SEL;
  58
  59         reg |= val << clk->bit_idx;
  60         writel(reg, clk->reg);
  61
  62         spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags);
  63
  64         return 0;
  65 }
  66
  67 static void clk_lpcg_scu_disable(struct clk_hw *hw)
  68 {
  69         struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
  70         unsigned long flags;
  71         u32 reg;
  72
  73         spin_lock_irqsave(&imx_lpcg_scu_lock, flags);
  74
  75         reg = readl_relaxed(clk->reg);
  76         reg &= ~(CLK_GATE_SCU_LPCG_MASK << clk->bit_idx);
  77         writel(reg, clk->reg);
  78
  79         spin_unlock_irqrestore(&imx_lpcg_scu_lock, flags);
  80 }
  81
  82 static const struct clk_ops clk_lpcg_scu_ops = {
  83         .enable = clk_lpcg_scu_enable,
  84         .disable = clk_lpcg_scu_disable,
  85 };
  86
  87 struct clk_hw *__imx_clk_lpcg_scu(struct device *dev, const char *name,
  88                                   const char *parent_name, unsigned long flags,
  89                                   void __iomem *reg, u8 bit_idx, bool hw_gate)
  90 {
  91         struct clk_lpcg_scu *clk;
  92         struct clk_init_data init;
  93         struct clk_hw *hw;
  94         int ret;
  95
  96         clk = kzalloc(sizeof(*clk), GFP_KERNEL);
  97         if (!clk)
  98                 return ERR_PTR(-ENOMEM);
  99
 100         clk->reg = reg;
 101         clk->bit_idx = bit_idx;
 102         clk->hw_gate = hw_gate;
 103
 104         init.name = name;
 105         init.ops = &clk_lpcg_scu_ops;
 106         init.flags = CLK_SET_RATE_PARENT | flags;
 107         init.parent_names = parent_name ? &parent_name : NULL;
 108         init.num_parents = parent_name ? 1 : 0;
 109
 110         clk->hw.init = &init;
 111
 112         hw = &clk->hw;
 113         ret = clk_hw_register(dev, hw);
 114         if (ret) {
 115                 kfree(clk);
 116                 hw = ERR_PTR(ret);
 117                 return hw;
 118         }
 119
 120         if (dev)
 121                 dev_set_drvdata(dev, clk);
 122
 123         return hw;
 124 }
 125
 126 void imx_clk_lpcg_scu_unregister(struct clk_hw *hw)
 127 {
 128         struct clk_lpcg_scu *clk = to_clk_lpcg_scu(hw);
 129
 130         clk_hw_unregister(&clk->hw);
 131         kfree(clk);
 132 }
 133
 134 static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
 135 {
 136         struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
 137
 138         clk->state = readl_relaxed(clk->reg);
 139         dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
 140
 141         return 0;
 142 }
 143
 144 static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
 145 {
 146         struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
 147
 148         /*
 149          * FIXME: Sometimes writes don't work unless the CPU issues
 150          * them twice
 151          */
 152
 153         writel(clk->state, clk->reg);
 154         writel(clk->state, clk->reg);
 155         dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);
 156
 157         return 0;
 158 }
 159
 160 const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops = {
 161         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_lpcg_scu_suspend,
 162                                       imx_clk_lpcg_scu_resume)
 163 };