1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2014 Free Electrons |
4 | * |
5 | * Author: Boris BREZILLON <boris.brezillon@free-electrons.com> |
6 | * |
7 | * Allwinner A31 AR100 clock driver |
8 | */ |
9 | |
10 | #include <linux/bitops.h> |
11 | #include <linux/clk-provider.h> |
12 | #include <linux/init.h> |
13 | #include <linux/of.h> |
14 | #include <linux/platform_device.h> |
15 | #include <linux/spinlock.h> |
16 | |
17 | #include "clk-factors.h" |
18 | |
19 | /* |
20 | * sun6i_get_ar100_factors - Calculates factors p, m for AR100 |
21 | * |
22 | * AR100 rate is calculated as follows |
23 | * rate = (parent_rate >> p) / (m + 1); |
24 | */ |
25 | static void sun6i_get_ar100_factors(struct factors_request *req) |
26 | { |
27 | unsigned long div; |
28 | int shift; |
29 | |
30 | /* clock only divides */ |
31 | if (req->rate > req->parent_rate) |
32 | req->rate = req->parent_rate; |
33 | |
34 | div = DIV_ROUND_UP(req->parent_rate, req->rate); |
35 | |
36 | if (div < 32) |
37 | shift = 0; |
38 | else if (div >> 1 < 32) |
39 | shift = 1; |
40 | else if (div >> 2 < 32) |
41 | shift = 2; |
42 | else |
43 | shift = 3; |
44 | |
45 | div >>= shift; |
46 | |
47 | if (div > 32) |
48 | div = 32; |
49 | |
50 | req->rate = (req->parent_rate >> shift) / div; |
51 | req->m = div - 1; |
52 | req->p = shift; |
53 | } |
54 | |
55 | static const struct clk_factors_config sun6i_ar100_config = { |
56 | .mwidth = 5, |
57 | .mshift = 8, |
58 | .pwidth = 2, |
59 | .pshift = 4, |
60 | }; |
61 | |
62 | static const struct factors_data sun6i_ar100_data = { |
63 | .mux = 16, |
64 | .muxmask = GENMASK(1, 0), |
65 | .table = &sun6i_ar100_config, |
66 | .getter = sun6i_get_ar100_factors, |
67 | }; |
68 | |
69 | static DEFINE_SPINLOCK(sun6i_ar100_lock); |
70 | |
71 | static int sun6i_a31_ar100_clk_probe(struct platform_device *pdev) |
72 | { |
73 | struct device_node *np = pdev->dev.of_node; |
74 | void __iomem *reg; |
75 | struct clk *clk; |
76 | |
77 | reg = devm_platform_ioremap_resource(pdev, index: 0); |
78 | if (IS_ERR(ptr: reg)) |
79 | return PTR_ERR(ptr: reg); |
80 | |
81 | clk = sunxi_factors_register(node: np, data: &sun6i_ar100_data, lock: &sun6i_ar100_lock, |
82 | reg); |
83 | if (!clk) |
84 | return -ENOMEM; |
85 | |
86 | platform_set_drvdata(pdev, data: clk); |
87 | |
88 | return 0; |
89 | } |
90 | |
91 | static const struct of_device_id sun6i_a31_ar100_clk_dt_ids[] = { |
92 | { .compatible = "allwinner,sun6i-a31-ar100-clk" }, |
93 | { /* sentinel */ } |
94 | }; |
95 | |
96 | static struct platform_driver sun6i_a31_ar100_clk_driver = { |
97 | .driver = { |
98 | .name = "sun6i-a31-ar100-clk" , |
99 | .of_match_table = sun6i_a31_ar100_clk_dt_ids, |
100 | .suppress_bind_attrs = true, |
101 | }, |
102 | .probe = sun6i_a31_ar100_clk_probe, |
103 | }; |
104 | builtin_platform_driver(sun6i_a31_ar100_clk_driver); |
105 | |