xref: /linux/drivers/video/fbdev/bt455.h (revision 8c57a5e7b2820f349c95b8c8393fec1e0f4070d2)
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  */
16 struct 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 
bt455_select_reg(struct bt455_regs * regs,int ir)27 static inline void bt455_select_reg(struct bt455_regs *regs, int ir)
28 {
29 	mb();
30 	regs->addr_cmap = ir & 0x0f;
31 }
32 
bt455_reset_reg(struct bt455_regs * regs)33 static 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  */
bt455_read_cmap_next(struct bt455_regs * regs,u8 * grey)42 static 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 
bt455_write_cmap_next(struct bt455_regs * regs,u8 grey)52 static 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 
bt455_write_ovly_next(struct bt455_regs * regs,u8 grey)62 static 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 
bt455_read_cmap_entry(struct bt455_regs * regs,int cr,u8 * grey)72 static 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 
bt455_write_cmap_entry(struct bt455_regs * regs,int cr,u8 grey)79 static 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 
bt455_write_ovly_entry(struct bt455_regs * regs,u8 grey)86 static 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