video/fbdev/bt455.h

0001 /*
0002  *  linux/drivers/video/bt455.h
0003  *
0004  *  Copyright 2003  Thiemo Seufer <seufer@csv.ica.uni-stuttgart.de>
0005  *  Copyright 2016  Maciej W. Rozycki <macro@linux-mips.org>
0006  *
0007  *  This file is subject to the terms and conditions of the GNU General
0008  *  Public License. See the file COPYING in the main directory of this
0009  *  archive for more details.
0010  */
0011 #include <linux/types.h>
0012
0013 /*
0014  * Bt455 byte-wide registers, 32-bit aligned.
0015  */
0016 struct bt455_regs {
0017     volatile u8 addr_cmap;
0018     u8 pad0[3];
0019     volatile u8 addr_cmap_data;
0020     u8 pad1[3];
0021     volatile u8 addr_clr;
0022     u8 pad2[3];
0023     volatile u8 addr_ovly;
0024     u8 pad3[3];
0025 };
0026
0027 static inline void bt455_select_reg(struct bt455_regs *regs, int ir)
0028 {
0029     mb();
0030     regs->addr_cmap = ir & 0x0f;
0031 }
0032
0033 static inline void bt455_reset_reg(struct bt455_regs *regs)
0034 {
0035     mb();
0036     regs->addr_clr = 0;
0037 }
0038
0039 /*
0040  * Read/write to a Bt455 color map register.
0041  */
0042 static inline void bt455_read_cmap_next(struct bt455_regs *regs, u8 *grey)
0043 {
0044     mb();
0045     regs->addr_cmap_data;
0046     rmb();
0047     *grey = regs->addr_cmap_data & 0xf;
0048     rmb();
0049     regs->addr_cmap_data;
0050 }
0051
0052 static inline void bt455_write_cmap_next(struct bt455_regs *regs, u8 grey)
0053 {
0054     wmb();
0055     regs->addr_cmap_data = 0x0;
0056     wmb();
0057     regs->addr_cmap_data = grey & 0xf;
0058     wmb();
0059     regs->addr_cmap_data = 0x0;
0060 }
0061
0062 static inline void bt455_write_ovly_next(struct bt455_regs *regs, u8 grey)
0063 {
0064     wmb();
0065     regs->addr_ovly = 0x0;
0066     wmb();
0067     regs->addr_ovly = grey & 0xf;
0068     wmb();
0069     regs->addr_ovly = 0x0;
0070 }
0071
0072 static inline void bt455_read_cmap_entry(struct bt455_regs *regs,
0073                      int cr, u8 *grey)
0074 {
0075     bt455_select_reg(regs, cr);
0076     bt455_read_cmap_next(regs, grey);
0077 }
0078
0079 static inline void bt455_write_cmap_entry(struct bt455_regs *regs,
0080                       int cr, u8 grey)
0081 {
0082     bt455_select_reg(regs, cr);
0083     bt455_write_cmap_next(regs, grey);
0084 }
0085
0086 static inline void bt455_write_ovly_entry(struct bt455_regs *regs, u8 grey)
0087 {
0088     bt455_reset_reg(regs);
0089     bt455_write_ovly_next(regs, grey);
0090 }