From 83912a99f13aa9f9f4e13ce2a393734658da9cd2 Mon Sep 17 00:00:00 2001 From: Trent Piepho Date: Wed, 4 Apr 2007 13:11:04 -0700 Subject: sn9c102: more efficient register writing code From: Trent Piepho There were many places in the driver which had long sequences of constant register initializations. These were done with one function call per register. The register address and value were immediate values in the function calls. This is very inefficient, as each register and value take twice the space when they are code, as each includes a push instruction to put it on the stack. There there is the overhead, both size and time, for a function call for each register. It's also quite a few lines of C code to do this. The patch creates a function that writes multiple registers from a list, and a macro that makes it easy to construct a such a list as a const static local to send to the function. This gets rid of quite a bit of C code, and shrinks the driver by around 8k, while at the same time being more efficient. Signed-off-by: Trent Piepho Acked-by: Luca Risolia --- .../media/video/sn9c102/sn9c102_pas202bcb.c | 74 ++++++++-------------- 1 file changed, 28 insertions(+), 46 deletions(-) (limited to 'linux/drivers/media/video/sn9c102/sn9c102_pas202bcb.c') diff --git a/linux/drivers/media/video/sn9c102/sn9c102_pas202bcb.c b/linux/drivers/media/video/sn9c102/sn9c102_pas202bcb.c index 4447d7cb1..c1b8d6b63 100644 --- a/linux/drivers/media/video/sn9c102/sn9c102_pas202bcb.c +++ b/linux/drivers/media/video/sn9c102/sn9c102_pas202bcb.c @@ -35,47 +35,29 @@ static int pas202bcb_init(struct sn9c102_device* cam) switch (sn9c102_get_bridge(cam)) { case BRIDGE_SN9C101: case BRIDGE_SN9C102: - err += sn9c102_write_reg(cam, 0x00, 0x10); - err += sn9c102_write_reg(cam, 0x00, 0x11); - err += sn9c102_write_reg(cam, 0x00, 0x14); - err += sn9c102_write_reg(cam, 0x20, 0x17); - err += sn9c102_write_reg(cam, 0x30, 0x19); - err += sn9c102_write_reg(cam, 0x09, 0x18); + err = sn9c102_write_const_regs(cam, {0x00, 0x10}, + {0x00, 0x11}, {0x00, 0x14}, + {0x20, 0x17}, {0x30, 0x19}, + {0x09, 0x18}); break; case BRIDGE_SN9C103: - err += sn9c102_write_reg(cam, 0x00, 0x02); - err += sn9c102_write_reg(cam, 0x00, 0x03); - err += sn9c102_write_reg(cam, 0x1a, 0x04); - err += sn9c102_write_reg(cam, 0x20, 0x05); - err += sn9c102_write_reg(cam, 0x20, 0x06); - err += sn9c102_write_reg(cam, 0x20, 0x07); - err += sn9c102_write_reg(cam, 0x00, 0x10); - err += sn9c102_write_reg(cam, 0x00, 0x11); - err += sn9c102_write_reg(cam, 0x00, 0x14); - err += sn9c102_write_reg(cam, 0x20, 0x17); - err += sn9c102_write_reg(cam, 0x30, 0x19); - err += sn9c102_write_reg(cam, 0x09, 0x18); - err += sn9c102_write_reg(cam, 0x02, 0x1c); - err += sn9c102_write_reg(cam, 0x03, 0x1d); - err += sn9c102_write_reg(cam, 0x0f, 0x1e); - err += sn9c102_write_reg(cam, 0x0c, 0x1f); - err += sn9c102_write_reg(cam, 0x00, 0x20); - err += sn9c102_write_reg(cam, 0x10, 0x21); - err += sn9c102_write_reg(cam, 0x20, 0x22); - err += sn9c102_write_reg(cam, 0x30, 0x23); - err += sn9c102_write_reg(cam, 0x40, 0x24); - err += sn9c102_write_reg(cam, 0x50, 0x25); - err += sn9c102_write_reg(cam, 0x60, 0x26); - err += sn9c102_write_reg(cam, 0x70, 0x27); - err += sn9c102_write_reg(cam, 0x80, 0x28); - err += sn9c102_write_reg(cam, 0x90, 0x29); - err += sn9c102_write_reg(cam, 0xa0, 0x2a); - err += sn9c102_write_reg(cam, 0xb0, 0x2b); - err += sn9c102_write_reg(cam, 0xc0, 0x2c); - err += sn9c102_write_reg(cam, 0xd0, 0x2d); - err += sn9c102_write_reg(cam, 0xe0, 0x2e); - err += sn9c102_write_reg(cam, 0xf0, 0x2f); - err += sn9c102_write_reg(cam, 0xff, 0x30); + err = sn9c102_write_const_regs(cam, {0x00, 0x02}, + {0x00, 0x03}, {0x1a, 0x04}, + {0x20, 0x05}, {0x20, 0x06}, + {0x20, 0x07}, {0x00, 0x10}, + {0x00, 0x11}, {0x00, 0x14}, + {0x20, 0x17}, {0x30, 0x19}, + {0x09, 0x18}, {0x02, 0x1c}, + {0x03, 0x1d}, {0x0f, 0x1e}, + {0x0c, 0x1f}, {0x00, 0x20}, + {0x10, 0x21}, {0x20, 0x22}, + {0x30, 0x23}, {0x40, 0x24}, + {0x50, 0x25}, {0x60, 0x26}, + {0x70, 0x27}, {0x80, 0x28}, + {0x90, 0x29}, {0xa0, 0x2a}, + {0xb0, 0x2b}, {0xc0, 0x2c}, + {0xd0, 0x2d}, {0xe0, 0x2e}, + {0xf0, 0x2f}, {0xff, 0x30}); break; default: break; @@ -325,15 +307,15 @@ int sn9c102_probe_pas202bcb(struct sn9c102_device* cam) switch (sn9c102_get_bridge(cam)) { case BRIDGE_SN9C101: case BRIDGE_SN9C102: - err += sn9c102_write_reg(cam, 0x01, 0x01); /* power down */ - err += sn9c102_write_reg(cam, 0x40, 0x01); /* power on */ - err += sn9c102_write_reg(cam, 0x28, 0x17); /* clock 24 MHz */ + err = sn9c102_write_const_regs(cam, + {0x01, 0x01}, /* power down */ + {0x40, 0x01}, /* power on */ + {0x28, 0x17});/* clock 24 MHz */ break; case BRIDGE_SN9C103: /* do _not_ change anything! */ - err += sn9c102_write_reg(cam, 0x09, 0x01); - err += sn9c102_write_reg(cam, 0x44, 0x01); - err += sn9c102_write_reg(cam, 0x44, 0x02); - err += sn9c102_write_reg(cam, 0x29, 0x17); + err = sn9c102_write_const_regs(cam, {0x09, 0x01}, + {0x44, 0x01}, {0x44, 0x02}, + {0x29, 0x17}); break; default: break; -- cgit v1.2.3