drivers/video/fbdev/bt455.h

   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
  27 static inline void bt455_select_reg(struct bt455_regs *regs, int ir)
  28 {
  29         mb();
  30         regs->addr_cmap = ir & 0x0f;
  31 }
  32
  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  */
  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
  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
  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
  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
  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
  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 }