1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License version 2 as 4 * published by the Free Software Foundation. 5 * 6 * This program is distributed in the hope that it will be useful, 7 * but WITHOUT ANY WARRANTY; without even the implied warranty of 8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 9 * GNU General Public License for more details. 10 * 11 * Copyright (C) 2012 ARM Limited 12 */ 13 14 #include <linux/clkdev.h> 15 #include <linux/clk-provider.h> 16 #include <linux/err.h> 17 #include <linux/of.h> 18 #include <linux/platform_device.h> 19 #include <linux/slab.h> 20 #include <linux/vexpress.h> 21 22 struct vexpress_osc { 23 struct regmap *reg; 24 struct clk_hw hw; 25 unsigned long rate_min; 26 unsigned long rate_max; 27 }; 28 29 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw) 30 31 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw, 32 unsigned long parent_rate) 33 { 34 struct vexpress_osc *osc = to_vexpress_osc(hw); 35 u32 rate; 36 37 regmap_read(osc->reg, 0, &rate); 38 39 return rate; 40 } 41 42 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate, 43 unsigned long *parent_rate) 44 { 45 struct vexpress_osc *osc = to_vexpress_osc(hw); 46 47 if (WARN_ON(osc->rate_min && rate < osc->rate_min)) 48 rate = osc->rate_min; 49 50 if (WARN_ON(osc->rate_max && rate > osc->rate_max)) 51 rate = osc->rate_max; 52 53 return rate; 54 } 55 56 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate, 57 unsigned long parent_rate) 58 { 59 struct vexpress_osc *osc = to_vexpress_osc(hw); 60 61 return regmap_write(osc->reg, 0, rate); 62 } 63 64 static struct clk_ops vexpress_osc_ops = { 65 .recalc_rate = vexpress_osc_recalc_rate, 66 .round_rate = vexpress_osc_round_rate, 67 .set_rate = vexpress_osc_set_rate, 68 }; 69 70 71 static int vexpress_osc_probe(struct platform_device *pdev) 72 { 73 struct clk_init_data init; 74 struct vexpress_osc *osc; 75 struct clk *clk; 76 u32 range[2]; 77 78 osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL); 79 if (!osc) 80 return -ENOMEM; 81 82 osc->reg = devm_regmap_init_vexpress_config(&pdev->dev); 83 if (IS_ERR(osc->reg)) 84 return PTR_ERR(osc->reg); 85 86 if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range, 87 ARRAY_SIZE(range)) == 0) { 88 osc->rate_min = range[0]; 89 osc->rate_max = range[1]; 90 } 91 92 if (of_property_read_string(pdev->dev.of_node, "clock-output-names", 93 &init.name) != 0) 94 init.name = dev_name(&pdev->dev); 95 96 init.ops = &vexpress_osc_ops; 97 init.flags = 0; 98 init.num_parents = 0; 99 100 osc->hw.init = &init; 101 102 clk = clk_register(NULL, &osc->hw); 103 if (IS_ERR(clk)) 104 return PTR_ERR(clk); 105 106 of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk); 107 108 dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name); 109 110 return 0; 111 } 112 113 static const struct of_device_id vexpress_osc_of_match[] = { 114 { .compatible = "arm,vexpress-osc", }, 115 {} 116 }; 117 118 static struct platform_driver vexpress_osc_driver = { 119 .driver = { 120 .name = "vexpress-osc", 121 .of_match_table = vexpress_osc_of_match, 122 }, 123 .probe = vexpress_osc_probe, 124 }; 125 126 static int __init vexpress_osc_init(void) 127 { 128 return platform_driver_register(&vexpress_osc_driver); 129 } 130 core_initcall(vexpress_osc_init); 131