forked from mirrors/linux
5832706e8b
Use the address autoincrement feature when accessing successive palette
entries and also skip loading a palette address in overlay register
assesses which do not use that address. Provide a red/green/blue
register sequencer reset helper for use in overlay register assesses
where the state of the sequencer is not known.
References:
[1] "Bt454 Bt455 170 MHz Monolithic CMOS 16 Color Palette RAMDAC",
Brooktree Corporation, Document Number: L454001, Rev. I
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
90 lines
1.8 KiB
C
90 lines
1.8 KiB
C
/*
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* linux/drivers/video/bt455.h
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*
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* Copyright 2003 Thiemo Seufer <seufer@csv.ica.uni-stuttgart.de>
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* Copyright 2016 Maciej W. Rozycki <macro@linux-mips.org>
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file COPYING in the main directory of this
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* archive for more details.
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*/
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#include <linux/types.h>
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/*
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* Bt455 byte-wide registers, 32-bit aligned.
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*/
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struct bt455_regs {
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volatile u8 addr_cmap;
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u8 pad0[3];
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volatile u8 addr_cmap_data;
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u8 pad1[3];
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volatile u8 addr_clr;
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u8 pad2[3];
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volatile u8 addr_ovly;
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u8 pad3[3];
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};
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static inline void bt455_select_reg(struct bt455_regs *regs, int ir)
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{
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mb();
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regs->addr_cmap = ir & 0x0f;
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}
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static inline void bt455_reset_reg(struct bt455_regs *regs)
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{
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mb();
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regs->addr_clr = 0;
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}
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/*
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* Read/write to a Bt455 color map register.
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*/
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static inline void bt455_read_cmap_next(struct bt455_regs *regs, u8 *grey)
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{
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mb();
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regs->addr_cmap_data;
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rmb();
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*grey = regs->addr_cmap_data & 0xf;
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rmb();
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regs->addr_cmap_data;
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}
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static inline void bt455_write_cmap_next(struct bt455_regs *regs, u8 grey)
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{
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wmb();
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regs->addr_cmap_data = 0x0;
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wmb();
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regs->addr_cmap_data = grey & 0xf;
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wmb();
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regs->addr_cmap_data = 0x0;
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}
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static inline void bt455_write_ovly_next(struct bt455_regs *regs, u8 grey)
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{
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wmb();
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regs->addr_ovly = 0x0;
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wmb();
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regs->addr_ovly = grey & 0xf;
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wmb();
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regs->addr_ovly = 0x0;
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}
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static inline void bt455_read_cmap_entry(struct bt455_regs *regs,
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int cr, u8 *grey)
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{
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bt455_select_reg(regs, cr);
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bt455_read_cmap_next(regs, grey);
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}
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static inline void bt455_write_cmap_entry(struct bt455_regs *regs,
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int cr, u8 grey)
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{
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bt455_select_reg(regs, cr);
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bt455_write_cmap_next(regs, grey);
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}
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static inline void bt455_write_ovly_entry(struct bt455_regs *regs, u8 grey)
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{
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bt455_reset_reg(regs);
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bt455_write_ovly_next(regs, grey);
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}
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