xref: /openbmc/linux/drivers/clk/mmp/reset.c (revision eb3fcf00)
1 #include <linux/slab.h>
2 #include <linux/io.h>
3 #include <linux/of.h>
4 #include <linux/of_address.h>
5 #include <linux/reset-controller.h>
6 
7 #include "reset.h"
8 
9 #define rcdev_to_unit(rcdev) container_of(rcdev, struct mmp_clk_reset_unit, rcdev)
10 
11 static int mmp_of_reset_xlate(struct reset_controller_dev *rcdev,
12 			  const struct of_phandle_args *reset_spec)
13 {
14 	struct mmp_clk_reset_unit *unit = rcdev_to_unit(rcdev);
15 	struct mmp_clk_reset_cell *cell;
16 	int i;
17 
18 	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
19 		return -EINVAL;
20 
21 	for (i = 0; i < rcdev->nr_resets; i++) {
22 		cell = &unit->cells[i];
23 		if (cell->clk_id == reset_spec->args[0])
24 			break;
25 	}
26 
27 	if (i == rcdev->nr_resets)
28 		return -EINVAL;
29 
30 	return i;
31 }
32 
33 static int mmp_clk_reset_assert(struct reset_controller_dev *rcdev,
34 				unsigned long id)
35 {
36 	struct mmp_clk_reset_unit *unit = rcdev_to_unit(rcdev);
37 	struct mmp_clk_reset_cell *cell;
38 	unsigned long flags = 0;
39 	u32 val;
40 
41 	cell = &unit->cells[id];
42 	if (cell->lock)
43 		spin_lock_irqsave(cell->lock, flags);
44 
45 	val = readl(cell->reg);
46 	val |= cell->bits;
47 	writel(val, cell->reg);
48 
49 	if (cell->lock)
50 		spin_unlock_irqrestore(cell->lock, flags);
51 
52 	return 0;
53 }
54 
55 static int mmp_clk_reset_deassert(struct reset_controller_dev *rcdev,
56 				unsigned long id)
57 {
58 	struct mmp_clk_reset_unit *unit = rcdev_to_unit(rcdev);
59 	struct mmp_clk_reset_cell *cell;
60 	unsigned long flags = 0;
61 	u32 val;
62 
63 	cell = &unit->cells[id];
64 	if (cell->lock)
65 		spin_lock_irqsave(cell->lock, flags);
66 
67 	val = readl(cell->reg);
68 	val &= ~cell->bits;
69 	writel(val, cell->reg);
70 
71 	if (cell->lock)
72 		spin_unlock_irqrestore(cell->lock, flags);
73 
74 	return 0;
75 }
76 
77 static struct reset_control_ops mmp_clk_reset_ops = {
78 	.assert		= mmp_clk_reset_assert,
79 	.deassert	= mmp_clk_reset_deassert,
80 };
81 
82 void mmp_clk_reset_register(struct device_node *np,
83 			struct mmp_clk_reset_cell *cells, int nr_resets)
84 {
85 	struct mmp_clk_reset_unit *unit;
86 
87 	unit = kzalloc(sizeof(*unit), GFP_KERNEL);
88 	if (!unit)
89 		return;
90 
91 	unit->cells = cells;
92 	unit->rcdev.of_reset_n_cells = 1;
93 	unit->rcdev.nr_resets = nr_resets;
94 	unit->rcdev.ops = &mmp_clk_reset_ops;
95 	unit->rcdev.of_node = np;
96 	unit->rcdev.of_xlate = mmp_of_reset_xlate;
97 
98 	reset_controller_register(&unit->rcdev);
99 }
100