UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity
OpenCloudOS-Kernel/include/linux/i2c-algo-bit.h

52 lines
2.1 KiB
C
Raw Normal View History

Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
/* ------------------------------------------------------------------------- */
/* i2c-algo-bit.h i2c driver algorithms for bit-shift adapters */
/* ------------------------------------------------------------------------- */
/* Copyright (C) 1995-99 Simon G. Vogl
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* ------------------------------------------------------------------------- */
/* With some changes from Ky<4B>sti M<>lkki <kmalkki@cc.hut.fi> and even
Frodo Looijaard <frodol@dds.nl> */
#ifndef _LINUX_I2C_ALGO_BIT_H
#define _LINUX_I2C_ALGO_BIT_H
/* --- Defines for bit-adapters --------------------------------------- */
/*
i2c: Whitespace cleanups Remove extraneous whitespace from various i2c headers and core files, like space-before-tab and whitespace at end of line. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-11 04:21:31 +08:00
* This struct contains the hw-dependent functions of bit-style adapters to
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
* manipulate the line states, and to init any hw-specific features. This is
i2c: Whitespace cleanups Remove extraneous whitespace from various i2c headers and core files, like space-before-tab and whitespace at end of line. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-11 04:21:31 +08:00
* only used if you have more than one hw-type of adapter running.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
*/
struct i2c_algo_bit_data {
void *data; /* private data for lowlevel routines */
void (*setsda) (void *data, int state);
void (*setscl) (void *data, int state);
int (*getsda) (void *data);
int (*getscl) (void *data);
/* local settings */
i2c-algo-bit: Implement a 50/50 SCL duty cycle The original i2c-algo-bit implementation uses a 33/66 SCL duty cycle when bits are being written on the bus. While the I2C specification doesn't forbid it, this prevents us from driving the I2C bus to its max speed, limiting us to 66 kbps max on standard I2C busses. Implementing a 50/50 duty cycle instead lets us max out the bandwidth up to the theoretical max of 100 kbps on standard I2C busses. This is particularly important when large amounts of data need to be transfered over the bus, as is the case with some TV adapters when the firmware is being uploaded. In fact this change even allows, at least in theory, fast-mode I2C support at 125, 166 and 250 kbps. There's no way to reach the theoretical max of 400 kbps with this implementation. But I don't think we want to put efforts in that direction anyway: software-driven I2C is very CPU-intensive and bad for latency. Other timing changes: * Don't set SDA high explicitly on error, we're going to issue a stop condition before we leave anyway. * If an error occurs when sending the slave address, yield the CPU before retrying, and remove the additional delay after the new start condition. Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:33 +08:00
int udelay; /* half clock cycle time in us,
minimum 2 us for fast-mode I2C,
minimum 5 us for standard-mode I2C and SMBus,
maximum 50 us for SMBus */
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
int timeout; /* in jiffies */
};
int i2c_bit_add_bus(struct i2c_adapter *);
i2c-algo-bit: Add i2c_bit_add_numbered_bus Add i2c_bit_add_numbered_bus(), which is equivalent to i2c_bit_add_bus except that it calls i2c_add_numbered_adapter() at the end instead of i2c_add_adapter(). Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-02 05:26:31 +08:00
int i2c_bit_add_numbered_bus(struct i2c_adapter *);
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 06:20:36 +08:00
#endif /* _LINUX_I2C_ALGO_BIT_H */