mirror of https://gitee.com/openkylin/linux.git
130 lines
3.3 KiB
C
130 lines
3.3 KiB
C
/* linux/drivers/i2c/busses/scx200_i2c.c
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Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
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National Semiconductor SCx200 I2C bus on GPIO pins
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Based on i2c-velleman.c Copyright (C) 1995-96, 2000 Simon G. Vogl
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-bit.h>
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#include <linux/io.h>
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#include <linux/scx200_gpio.h>
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MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
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MODULE_DESCRIPTION("NatSemi SCx200 I2C Driver");
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MODULE_LICENSE("GPL");
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static int scl = CONFIG_SCx200_I2C_SCL;
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static int sda = CONFIG_SCx200_I2C_SDA;
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module_param(scl, int, 0);
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MODULE_PARM_DESC(scl, "GPIO line for SCL");
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module_param(sda, int, 0);
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MODULE_PARM_DESC(sda, "GPIO line for SDA");
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static void scx200_i2c_setscl(void *data, int state)
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{
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scx200_gpio_set(scl, state);
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}
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static void scx200_i2c_setsda(void *data, int state)
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{
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scx200_gpio_set(sda, state);
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}
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static int scx200_i2c_getscl(void *data)
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{
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return scx200_gpio_get(scl);
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}
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static int scx200_i2c_getsda(void *data)
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{
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return scx200_gpio_get(sda);
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}
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/* ------------------------------------------------------------------------
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* Encapsulate the above functions in the correct operations structure.
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* This is only done when more than one hardware adapter is supported.
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*/
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static struct i2c_algo_bit_data scx200_i2c_data = {
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.setsda = scx200_i2c_setsda,
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.setscl = scx200_i2c_setscl,
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.getsda = scx200_i2c_getsda,
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.getscl = scx200_i2c_getscl,
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.udelay = 10,
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.timeout = HZ,
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};
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static struct i2c_adapter scx200_i2c_ops = {
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.owner = THIS_MODULE,
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.class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
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.algo_data = &scx200_i2c_data,
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.name = "NatSemi SCx200 I2C",
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};
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static int scx200_i2c_init(void)
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{
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pr_debug("NatSemi SCx200 I2C Driver\n");
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if (!scx200_gpio_present()) {
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pr_err("no SCx200 gpio pins available\n");
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return -ENODEV;
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}
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pr_debug("SCL=GPIO%02u, SDA=GPIO%02u\n", scl, sda);
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if (scl == -1 || sda == -1 || scl == sda) {
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pr_err("scl and sda must be specified\n");
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return -EINVAL;
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}
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/* Configure GPIOs as open collector outputs */
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scx200_gpio_configure(scl, ~2, 5);
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scx200_gpio_configure(sda, ~2, 5);
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if (i2c_bit_add_bus(&scx200_i2c_ops) < 0) {
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pr_err("adapter %s registration failed\n", scx200_i2c_ops.name);
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return -ENODEV;
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}
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return 0;
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}
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static void scx200_i2c_cleanup(void)
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{
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i2c_del_adapter(&scx200_i2c_ops);
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}
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module_init(scx200_i2c_init);
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module_exit(scx200_i2c_cleanup);
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/*
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Local variables:
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compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules"
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c-basic-offset: 8
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End:
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*/
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