1 /* 2 * Driver for the ICST307 VCO clock found in the ARM Reference designs. 3 * We wrap the custom interface from <asm/hardware/icst.h> into the generic 4 * clock framework. 5 * 6 * Copyright (C) 2012 Linus Walleij 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 * TODO: when all ARM reference designs are migrated to generic clocks, the 13 * ICST clock code from the ARM tree should probably be merged into this 14 * file. 15 */ 16 #include <linux/clk.h> 17 #include <linux/clkdev.h> 18 #include <linux/err.h> 19 #include <linux/clk-provider.h> 20 #include <linux/io.h> 21 22 #include "clk-icst.h" 23 24 /** 25 * struct clk_icst - ICST VCO clock wrapper 26 * @hw: corresponding clock hardware entry 27 * @vcoreg: VCO register address 28 * @lockreg: VCO lock register address 29 * @params: parameters for this ICST instance 30 * @rate: current rate 31 */ 32 struct clk_icst { 33 struct clk_hw hw; 34 void __iomem *vcoreg; 35 void __iomem *lockreg; 36 const struct icst_params *params; 37 unsigned long rate; 38 }; 39 40 #define to_icst(_hw) container_of(_hw, struct clk_icst, hw) 41 42 /** 43 * vco_get() - get ICST VCO settings from a certain register 44 * @vcoreg: register containing the VCO settings 45 */ 46 static struct icst_vco vco_get(void __iomem *vcoreg) 47 { 48 u32 val; 49 struct icst_vco vco; 50 51 val = readl(vcoreg); 52 vco.v = val & 0x1ff; 53 vco.r = (val >> 9) & 0x7f; 54 vco.s = (val >> 16) & 03; 55 return vco; 56 } 57 58 /** 59 * vco_set() - commit changes to an ICST VCO 60 * @locreg: register to poke to unlock the VCO for writing 61 * @vcoreg: register containing the VCO settings 62 * @vco: ICST VCO parameters to commit 63 */ 64 static void vco_set(void __iomem *lockreg, 65 void __iomem *vcoreg, 66 struct icst_vco vco) 67 { 68 u32 val; 69 70 val = readl(vcoreg) & ~0x7ffff; 71 val |= vco.v | (vco.r << 9) | (vco.s << 16); 72 73 /* This magic unlocks the VCO so it can be controlled */ 74 writel(0xa05f, lockreg); 75 writel(val, vcoreg); 76 /* This locks the VCO again */ 77 writel(0, lockreg); 78 } 79 80 81 static unsigned long icst_recalc_rate(struct clk_hw *hw, 82 unsigned long parent_rate) 83 { 84 struct clk_icst *icst = to_icst(hw); 85 struct icst_vco vco; 86 87 vco = vco_get(icst->vcoreg); 88 icst->rate = icst_hz(icst->params, vco); 89 return icst->rate; 90 } 91 92 static long icst_round_rate(struct clk_hw *hw, unsigned long rate, 93 unsigned long *prate) 94 { 95 struct clk_icst *icst = to_icst(hw); 96 struct icst_vco vco; 97 98 vco = icst_hz_to_vco(icst->params, rate); 99 return icst_hz(icst->params, vco); 100 } 101 102 static int icst_set_rate(struct clk_hw *hw, unsigned long rate, 103 unsigned long parent_rate) 104 { 105 struct clk_icst *icst = to_icst(hw); 106 struct icst_vco vco; 107 108 vco = icst_hz_to_vco(icst->params, rate); 109 icst->rate = icst_hz(icst->params, vco); 110 vco_set(icst->lockreg, icst->vcoreg, vco); 111 return 0; 112 } 113 114 static const struct clk_ops icst_ops = { 115 .recalc_rate = icst_recalc_rate, 116 .round_rate = icst_round_rate, 117 .set_rate = icst_set_rate, 118 }; 119 120 struct clk *icst_clk_register(struct device *dev, 121 const struct clk_icst_desc *desc, 122 void __iomem *base) 123 { 124 struct clk *clk; 125 struct clk_icst *icst; 126 struct clk_init_data init; 127 128 icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL); 129 if (!icst) { 130 pr_err("could not allocate ICST clock!\n"); 131 return ERR_PTR(-ENOMEM); 132 } 133 init.name = "icst"; 134 init.ops = &icst_ops; 135 init.flags = CLK_IS_ROOT; 136 init.parent_names = NULL; 137 init.num_parents = 0; 138 icst->hw.init = &init; 139 icst->params = desc->params; 140 icst->vcoreg = base + desc->vco_offset; 141 icst->lockreg = base + desc->lock_offset; 142 143 clk = clk_register(dev, &icst->hw); 144 if (IS_ERR(clk)) 145 kfree(icst); 146 147 return clk; 148 } 149