xref: /openbmc/linux/drivers/clk/imx/clk.c (revision e2f1cf25)
1 #include <linux/clk.h>
2 #include <linux/err.h>
3 #include <linux/of.h>
4 #include <linux/slab.h>
5 #include <linux/spinlock.h>
6 #include "clk.h"
7 
8 DEFINE_SPINLOCK(imx_ccm_lock);
9 
10 void __init imx_check_clocks(struct clk *clks[], unsigned int count)
11 {
12 	unsigned i;
13 
14 	for (i = 0; i < count; i++)
15 		if (IS_ERR(clks[i]))
16 			pr_err("i.MX clk %u: register failed with %ld\n",
17 			       i, PTR_ERR(clks[i]));
18 }
19 
20 static struct clk * __init imx_obtain_fixed_clock_from_dt(const char *name)
21 {
22 	struct of_phandle_args phandle;
23 	struct clk *clk = ERR_PTR(-ENODEV);
24 	char *path;
25 
26 	path = kasprintf(GFP_KERNEL, "/clocks/%s", name);
27 	if (!path)
28 		return ERR_PTR(-ENOMEM);
29 
30 	phandle.np = of_find_node_by_path(path);
31 	kfree(path);
32 
33 	if (phandle.np) {
34 		clk = of_clk_get_from_provider(&phandle);
35 		of_node_put(phandle.np);
36 	}
37 	return clk;
38 }
39 
40 struct clk * __init imx_obtain_fixed_clock(
41 			const char *name, unsigned long rate)
42 {
43 	struct clk *clk;
44 
45 	clk = imx_obtain_fixed_clock_from_dt(name);
46 	if (IS_ERR(clk))
47 		clk = imx_clk_fixed(name, rate);
48 	return clk;
49 }
50 
51 /*
52  * This fixups the register CCM_CSCMR1 write value.
53  * The write/read/divider values of the aclk_podf field
54  * of that register have the relationship described by
55  * the following table:
56  *
57  * write value       read value        divider
58  * 3b'000            3b'110            7
59  * 3b'001            3b'111            8
60  * 3b'010            3b'100            5
61  * 3b'011            3b'101            6
62  * 3b'100            3b'010            3
63  * 3b'101            3b'011            4
64  * 3b'110            3b'000            1
65  * 3b'111            3b'001            2(default)
66  *
67  * That's why we do the xor operation below.
68  */
69 #define CSCMR1_FIXUP	0x00600000
70 
71 void imx_cscmr1_fixup(u32 *val)
72 {
73 	*val ^= CSCMR1_FIXUP;
74 	return;
75 }
76