bd5d080ab9
Patch from Richard Purdie Add a driver for the extra GPIOs found on the Sharp SL-C1000 (Akita). These GPIOs are found on a Maxim MAX7310 I2C i/o expander chip. A generic GPIO driver for the MAX7310 was attempted but this mini driver is a much simpler and much more effective solution avoiding several issues and complexity the generic driver had (as discussed on LKML). The platform device is required so the device parent can be set correctly which ensures the device is one of the last to suspend and first to resume. Whilst the i2c suspend/resume calls can be influenced, nothing guarantees this is easlier/later than the subsystems the gpios are used on which are all independent of i2c (sound, irda, video/backlight etc.). Signed-off-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
224 lines
4.8 KiB
C
224 lines
4.8 KiB
C
/*
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* Support for the Extra GPIOs on the Sharp SL-C1000 (Akita)
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* (uses a Maxim MAX7310 8 Port IO Expander)
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*
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* Copyright 2005 Openedhand Ltd.
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*
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* Author: Richard Purdie <richard@openedhand.com>
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*
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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 version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <asm/arch/akita.h>
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/* MAX7310 Regiser Map */
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#define MAX7310_INPUT 0x00
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#define MAX7310_OUTPUT 0x01
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#define MAX7310_POLINV 0x02
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#define MAX7310_IODIR 0x03 /* 1 = Input, 0 = Output */
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#define MAX7310_TIMEOUT 0x04
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/* Addresses to scan */
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static unsigned short normal_i2c[] = { 0x18, I2C_CLIENT_END };
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/* I2C Magic */
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I2C_CLIENT_INSMOD;
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static int max7310_write(struct i2c_client *client, int address, int data);
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static struct i2c_client max7310_template;
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static void akita_ioexp_work(void *private_);
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static struct device *akita_ioexp_device;
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static unsigned char ioexp_output_value = AKITA_IOEXP_IO_OUT;
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DECLARE_WORK(akita_ioexp, akita_ioexp_work, NULL);
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/*
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* MAX7310 Access
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*/
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static int max7310_config(struct device *dev, int iomode, int polarity)
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{
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int ret;
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struct i2c_client *client = to_i2c_client(dev);
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ret = max7310_write(client, MAX7310_POLINV, polarity);
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if (ret < 0)
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return ret;
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ret = max7310_write(client, MAX7310_IODIR, iomode);
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return ret;
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}
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static int max7310_set_ouputs(struct device *dev, int outputs)
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{
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struct i2c_client *client = to_i2c_client(dev);
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return max7310_write(client, MAX7310_OUTPUT, outputs);
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}
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/*
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* I2C Functions
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*/
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static int max7310_write(struct i2c_client *client, int address, int value)
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{
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u8 data[2];
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data[0] = address & 0xff;
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data[1] = value & 0xff;
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if (i2c_master_send(client, data, 2) == 2)
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return 0;
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return -1;
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}
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static int max7310_detect(struct i2c_adapter *adapter, int address, int kind)
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{
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struct i2c_client *new_client;
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int err;
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if (!(new_client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL)))
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return -ENOMEM;
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max7310_template.adapter = adapter;
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max7310_template.addr = address;
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memcpy(new_client, &max7310_template, sizeof(struct i2c_client));
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if ((err = i2c_attach_client(new_client))) {
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kfree(new_client);
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return err;
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}
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max7310_config(&new_client->dev, AKITA_IOEXP_IO_DIR, 0);
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akita_ioexp_device = &new_client->dev;
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schedule_work(&akita_ioexp);
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return 0;
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}
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static int max7310_attach_adapter(struct i2c_adapter *adapter)
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{
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return i2c_probe(adapter, &addr_data, max7310_detect);
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}
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static int max7310_detach_client(struct i2c_client *client)
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{
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int err;
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akita_ioexp_device = NULL;
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if ((err = i2c_detach_client(client)))
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return err;
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kfree(client);
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return 0;
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}
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static struct i2c_driver max7310_i2c_driver = {
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.owner = THIS_MODULE,
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.name = "akita-max7310",
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.id = I2C_DRIVERID_AKITAIOEXP,
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.flags = I2C_DF_NOTIFY,
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.attach_adapter = max7310_attach_adapter,
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.detach_client = max7310_detach_client,
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};
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static struct i2c_client max7310_template = {
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name: "akita-max7310",
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flags: I2C_CLIENT_ALLOW_USE,
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driver: &max7310_i2c_driver,
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};
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void akita_set_ioexp(struct device *dev, unsigned char bit)
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{
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ioexp_output_value |= bit;
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if (akita_ioexp_device)
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schedule_work(&akita_ioexp);
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return;
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}
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void akita_reset_ioexp(struct device *dev, unsigned char bit)
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{
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ioexp_output_value &= ~bit;
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if (akita_ioexp_device)
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schedule_work(&akita_ioexp);
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return;
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}
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EXPORT_SYMBOL(akita_set_ioexp);
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EXPORT_SYMBOL(akita_reset_ioexp);
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static void akita_ioexp_work(void *private_)
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{
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if (akita_ioexp_device)
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max7310_set_ouputs(akita_ioexp_device, ioexp_output_value);
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}
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#ifdef CONFIG_PM
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static int akita_ioexp_suspend(struct platform_device *pdev, pm_message_t state)
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{
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flush_scheduled_work();
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return 0;
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}
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static int akita_ioexp_resume(struct platform_device *pdev)
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{
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schedule_work(&akita_ioexp);
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return 0;
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}
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#else
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#define akita_ioexp_suspend NULL
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#define akita_ioexp_resume NULL
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#endif
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static int __init akita_ioexp_probe(struct platform_device *pdev)
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{
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return i2c_add_driver(&max7310_i2c_driver);
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}
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static int akita_ioexp_remove(struct platform_device *pdev)
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{
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i2c_del_driver(&max7310_i2c_driver);
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return 0;
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}
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static struct platform_driver akita_ioexp_driver = {
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.probe = akita_ioexp_probe,
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.remove = akita_ioexp_remove,
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.suspend = akita_ioexp_suspend,
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.resume = akita_ioexp_resume,
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.driver = {
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.name = "akita-ioexp",
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},
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};
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static int __init akita_ioexp_init(void)
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{
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return platform_driver_register(&akita_ioexp_driver);
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}
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static void __exit akita_ioexp_exit(void)
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{
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platform_driver_unregister(&akita_ioexp_driver);
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}
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MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
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MODULE_DESCRIPTION("Akita IO-Expander driver");
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MODULE_LICENSE("GPL");
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fs_initcall(akita_ioexp_init);
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module_exit(akita_ioexp_exit);
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