1/*
2 *	linux/drivers/video/bt455.h
3 *
4 *	Copyright 2003  Thiemo Seufer <seufer@csv.ica.uni-stuttgart.de>
5 *	Copyright 2016  Maciej W. Rozycki <macro@linux-mips.org>
6 *
7 *	This file is subject to the terms and conditions of the GNU General
8 *	Public License. See the file COPYING in the main directory of this
9 *	archive for more details.
10 */
11#include <linux/types.h>
12
13/*
14 * Bt455 byte-wide registers, 32-bit aligned.
15 */
16struct bt455_regs {
17	volatile u8 addr_cmap;
18	u8 pad0[3];
19	volatile u8 addr_cmap_data;
20	u8 pad1[3];
21	volatile u8 addr_clr;
22	u8 pad2[3];
23	volatile u8 addr_ovly;
24	u8 pad3[3];
25};
26
27static inline void bt455_select_reg(struct bt455_regs *regs, int ir)
28{
29	mb();
30	regs->addr_cmap = ir & 0x0f;
31}
32
33static inline void bt455_reset_reg(struct bt455_regs *regs)
34{
35	mb();
36	regs->addr_clr = 0;
37}
38
39/*
40 * Read/write to a Bt455 color map register.
41 */
42static inline void bt455_read_cmap_next(struct bt455_regs *regs, u8 *grey)
43{
44	mb();
45	regs->addr_cmap_data;
46	rmb();
47	*grey = regs->addr_cmap_data & 0xf;
48	rmb();
49	regs->addr_cmap_data;
50}
51
52static inline void bt455_write_cmap_next(struct bt455_regs *regs, u8 grey)
53{
54	wmb();
55	regs->addr_cmap_data = 0x0;
56	wmb();
57	regs->addr_cmap_data = grey & 0xf;
58	wmb();
59	regs->addr_cmap_data = 0x0;
60}
61
62static inline void bt455_write_ovly_next(struct bt455_regs *regs, u8 grey)
63{
64	wmb();
65	regs->addr_ovly = 0x0;
66	wmb();
67	regs->addr_ovly = grey & 0xf;
68	wmb();
69	regs->addr_ovly = 0x0;
70}
71
72static inline void bt455_read_cmap_entry(struct bt455_regs *regs,
73					 int cr, u8 *grey)
74{
75	bt455_select_reg(regs, cr);
76	bt455_read_cmap_next(regs, grey);
77}
78
79static inline void bt455_write_cmap_entry(struct bt455_regs *regs,
80					  int cr, u8 grey)
81{
82	bt455_select_reg(regs, cr);
83	bt455_write_cmap_next(regs, grey);
84}
85
86static inline void bt455_write_ovly_entry(struct bt455_regs *regs, u8 grey)
87{
88	bt455_reset_reg(regs);
89	bt455_write_ovly_next(regs, grey);
90}
91