2 * Clock Driver for Allo DAC
4 * Author: Baswaraj K <jaikumar@cem-solutions.net>
6 * based on code by Stuart MacLean
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
18 #include <linux/clk-provider.h>
19 #include <linux/clkdev.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
23 #include <linux/slab.h>
24 #include <linux/platform_device.h>
26 /* Clock rate of CLK44EN attached to GPIO6 pin */
27 #define CLK_44EN_RATE 45158400UL
28 /* Clock rate of CLK48EN attached to GPIO3 pin */
29 #define CLK_48EN_RATE 49152000UL
32 * struct allo_dac_clk - Common struct to the Allo DAC
33 * @hw: clk_hw for the common clk framework
34 * @mode: 0 => CLK44EN, 1 => CLK48EN
41 #define to_allo_clk(_hw) container_of(_hw, struct clk_allo_hw, hw)
43 static const struct of_device_id clk_allo_dac_dt_ids[] = {
44 { .compatible = "allo,dac-clk",},
47 MODULE_DEVICE_TABLE(of, clk_allo_dac_dt_ids);
49 static unsigned long clk_allo_dac_recalc_rate(struct clk_hw *hw,
50 unsigned long parent_rate)
52 return (to_allo_clk(hw)->mode == 0) ? CLK_44EN_RATE :
56 static long clk_allo_dac_round_rate(struct clk_hw *hw,
57 unsigned long rate, unsigned long *parent_rate)
61 if (rate <= CLK_44EN_RATE) {
62 actual_rate = (long)CLK_44EN_RATE;
63 } else if (rate >= CLK_48EN_RATE) {
64 actual_rate = (long)CLK_48EN_RATE;
66 long diff44Rate = (long)(rate - CLK_44EN_RATE);
67 long diff48Rate = (long)(CLK_48EN_RATE - rate);
69 if (diff44Rate < diff48Rate)
70 actual_rate = (long)CLK_44EN_RATE;
72 actual_rate = (long)CLK_48EN_RATE;
78 static int clk_allo_dac_set_rate(struct clk_hw *hw,
79 unsigned long rate, unsigned long parent_rate)
81 unsigned long actual_rate;
82 struct clk_allo_hw *clk = to_allo_clk(hw);
84 actual_rate = (unsigned long)clk_allo_dac_round_rate(hw, rate,
86 clk->mode = (actual_rate == CLK_44EN_RATE) ? 0 : 1;
91 const struct clk_ops clk_allo_dac_rate_ops = {
92 .recalc_rate = clk_allo_dac_recalc_rate,
93 .round_rate = clk_allo_dac_round_rate,
94 .set_rate = clk_allo_dac_set_rate,
97 static int clk_allo_dac_probe(struct platform_device *pdev)
100 struct clk_allo_hw *proclk;
103 struct clk_init_data init;
107 proclk = kzalloc(sizeof(struct clk_allo_hw), GFP_KERNEL);
111 init.name = "clk-allo-dac";
112 init.ops = &clk_allo_dac_rate_ops;
114 init.parent_names = NULL;
115 init.num_parents = 0;
118 proclk->hw.init = &init;
120 clk = devm_clk_register(dev, &proclk->hw);
122 ret = of_clk_add_provider(dev->of_node, of_clk_src_simple_get,
125 dev_err(dev, "Fail to register clock driver\n");
132 static int clk_allo_dac_remove(struct platform_device *pdev)
134 of_clk_del_provider(pdev->dev.of_node);
138 static struct platform_driver clk_allo_dac_driver = {
139 .probe = clk_allo_dac_probe,
140 .remove = clk_allo_dac_remove,
142 .name = "clk-allo-dac",
143 .of_match_table = clk_allo_dac_dt_ids,
147 static int __init clk_allo_dac_init(void)
149 return platform_driver_register(&clk_allo_dac_driver);
151 core_initcall(clk_allo_dac_init);
153 static void __exit clk_allo_dac_exit(void)
155 platform_driver_unregister(&clk_allo_dac_driver);
157 module_exit(clk_allo_dac_exit);
159 MODULE_DESCRIPTION("Allo DAC clock driver");
160 MODULE_LICENSE("GPL v2");
161 MODULE_ALIAS("platform:clk-allo-dac");