xref: /openbmc/linux/drivers/clk/versatile/clk-icst.c (revision 15e47304)
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  * TODO: when all ARM reference designs are migrated to generic clocks, the
7  * ICST clock code from the ARM tree should probably be merged into this
8  * file.
9  */
10 #include <linux/clk.h>
11 #include <linux/clkdev.h>
12 #include <linux/err.h>
13 #include <linux/clk-provider.h>
14 
15 #include "clk-icst.h"
16 
17 /**
18  * struct clk_icst - ICST VCO clock wrapper
19  * @hw: corresponding clock hardware entry
20  * @params: parameters for this ICST instance
21  * @rate: current rate
22  * @setvco: function to commit ICST settings to hardware
23  */
24 struct clk_icst {
25 	struct clk_hw hw;
26 	const struct icst_params *params;
27 	unsigned long rate;
28 	struct icst_vco (*getvco)(void);
29 	void (*setvco)(struct icst_vco);
30 };
31 
32 #define to_icst(_hw) container_of(_hw, struct clk_icst, hw)
33 
34 static unsigned long icst_recalc_rate(struct clk_hw *hw,
35 				      unsigned long parent_rate)
36 {
37 	struct clk_icst *icst = to_icst(hw);
38 	struct icst_vco vco;
39 
40 	vco = icst->getvco();
41 	icst->rate = icst_hz(icst->params, vco);
42 	return icst->rate;
43 }
44 
45 static long icst_round_rate(struct clk_hw *hw, unsigned long rate,
46 			    unsigned long *prate)
47 {
48 	struct clk_icst *icst = to_icst(hw);
49 	struct icst_vco vco;
50 
51 	vco = icst_hz_to_vco(icst->params, rate);
52 	return icst_hz(icst->params, vco);
53 }
54 
55 static int icst_set_rate(struct clk_hw *hw, unsigned long rate,
56 			 unsigned long parent_rate)
57 {
58 	struct clk_icst *icst = to_icst(hw);
59 	struct icst_vco vco;
60 
61 	vco = icst_hz_to_vco(icst->params, rate);
62 	icst->rate = icst_hz(icst->params, vco);
63 	icst->setvco(vco);
64 	return 0;
65 }
66 
67 static const struct clk_ops icst_ops = {
68 	.recalc_rate = icst_recalc_rate,
69 	.round_rate = icst_round_rate,
70 	.set_rate = icst_set_rate,
71 };
72 
73 struct clk * __init icst_clk_register(struct device *dev,
74 				      const struct clk_icst_desc *desc)
75 {
76 	struct clk *clk;
77 	struct clk_icst *icst;
78 	struct clk_init_data init;
79 
80 	icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL);
81 	if (!icst) {
82 		pr_err("could not allocate ICST clock!\n");
83 		return ERR_PTR(-ENOMEM);
84 	}
85 	init.name = "icst";
86 	init.ops = &icst_ops;
87 	init.flags = CLK_IS_ROOT;
88 	init.parent_names = NULL;
89 	init.num_parents = 0;
90 	icst->hw.init = &init;
91 	icst->params = desc->params;
92 	icst->getvco = desc->getvco;
93 	icst->setvco = desc->setvco;
94 
95 	clk = clk_register(dev, &icst->hw);
96 	if (IS_ERR(clk))
97 		kfree(icst);
98 
99 	return clk;
100 }
101