1 /* 2 * clk-h32mx.c 3 * 4 * Copyright (C) 2014 Atmel 5 * 6 * Alexandre Belloni <alexandre.belloni@free-electrons.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 as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 */ 14 15 #include <linux/clk-provider.h> 16 #include <linux/clkdev.h> 17 #include <linux/clk/at91_pmc.h> 18 #include <linux/of.h> 19 #include <linux/regmap.h> 20 #include <linux/mfd/syscon.h> 21 22 #include "pmc.h" 23 24 #define H32MX_MAX_FREQ 90000000 25 26 struct clk_sama5d4_h32mx { 27 struct clk_hw hw; 28 struct regmap *regmap; 29 }; 30 31 #define to_clk_sama5d4_h32mx(hw) container_of(hw, struct clk_sama5d4_h32mx, hw) 32 33 static unsigned long clk_sama5d4_h32mx_recalc_rate(struct clk_hw *hw, 34 unsigned long parent_rate) 35 { 36 struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw); 37 unsigned int mckr; 38 39 regmap_read(h32mxclk->regmap, AT91_PMC_MCKR, &mckr); 40 if (mckr & AT91_PMC_H32MXDIV) 41 return parent_rate / 2; 42 43 if (parent_rate > H32MX_MAX_FREQ) 44 pr_warn("H32MX clock is too fast\n"); 45 return parent_rate; 46 } 47 48 static long clk_sama5d4_h32mx_round_rate(struct clk_hw *hw, unsigned long rate, 49 unsigned long *parent_rate) 50 { 51 unsigned long div; 52 53 if (rate > *parent_rate) 54 return *parent_rate; 55 div = *parent_rate / 2; 56 if (rate < div) 57 return div; 58 59 if (rate - div < *parent_rate - rate) 60 return div; 61 62 return *parent_rate; 63 } 64 65 static int clk_sama5d4_h32mx_set_rate(struct clk_hw *hw, unsigned long rate, 66 unsigned long parent_rate) 67 { 68 struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw); 69 u32 mckr = 0; 70 71 if (parent_rate != rate && (parent_rate / 2) != rate) 72 return -EINVAL; 73 74 if ((parent_rate / 2) == rate) 75 mckr = AT91_PMC_H32MXDIV; 76 77 regmap_update_bits(h32mxclk->regmap, AT91_PMC_MCKR, 78 AT91_PMC_H32MXDIV, mckr); 79 80 return 0; 81 } 82 83 static const struct clk_ops h32mx_ops = { 84 .recalc_rate = clk_sama5d4_h32mx_recalc_rate, 85 .round_rate = clk_sama5d4_h32mx_round_rate, 86 .set_rate = clk_sama5d4_h32mx_set_rate, 87 }; 88 89 struct clk_hw * __init 90 at91_clk_register_h32mx(struct regmap *regmap, const char *name, 91 const char *parent_name) 92 { 93 struct clk_sama5d4_h32mx *h32mxclk; 94 struct clk_init_data init; 95 int ret; 96 97 h32mxclk = kzalloc(sizeof(*h32mxclk), GFP_KERNEL); 98 if (!h32mxclk) 99 return ERR_PTR(-ENOMEM); 100 101 init.name = name; 102 init.ops = &h32mx_ops; 103 init.parent_names = parent_name ? &parent_name : NULL; 104 init.num_parents = parent_name ? 1 : 0; 105 init.flags = CLK_SET_RATE_GATE; 106 107 h32mxclk->hw.init = &init; 108 h32mxclk->regmap = regmap; 109 110 ret = clk_hw_register(NULL, &h32mxclk->hw); 111 if (ret) { 112 kfree(h32mxclk); 113 return ERR_PTR(ret); 114 } 115 116 return &h32mxclk->hw; 117 } 118