4c4d887822
This saves us allocating an array on the stack, giving a meaningless performance improvement and ensuring that if drivers ever do large writes we'll not allocate large arrays on the stack. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
/*
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* wm831x-i2c.c -- I2C access for Wolfson WM831x PMICs
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*
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* Copyright 2009,2010 Wolfson Microelectronics PLC.
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*
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* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/delay.h>
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#include <linux/mfd/core.h>
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#include <linux/slab.h>
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#include <linux/mfd/wm831x/core.h>
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#include <linux/mfd/wm831x/pdata.h>
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static int wm831x_i2c_read_device(struct wm831x *wm831x, unsigned short reg,
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int bytes, void *dest)
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{
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struct i2c_client *i2c = wm831x->control_data;
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int ret;
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u16 r = cpu_to_be16(reg);
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ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
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if (ret < 0)
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return ret;
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if (ret != 2)
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return -EIO;
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ret = i2c_master_recv(i2c, dest, bytes);
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if (ret < 0)
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return ret;
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if (ret != bytes)
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return -EIO;
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return 0;
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}
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/* Currently we allocate the write buffer on the stack; this is OK for
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* small writes - if we need to do large writes this will need to be
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* revised.
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*/
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static int wm831x_i2c_write_device(struct wm831x *wm831x, unsigned short reg,
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int bytes, void *src)
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{
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struct i2c_client *i2c = wm831x->control_data;
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struct i2c_msg xfer[2];
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int ret;
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reg = cpu_to_be16(reg);
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xfer[0].addr = i2c->addr;
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xfer[0].flags = 0;
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xfer[0].len = 2;
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xfer[0].buf = (char *)®
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xfer[1].addr = i2c->addr;
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xfer[1].flags = I2C_M_NOSTART;
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xfer[1].len = bytes;
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xfer[1].buf = (char *)src;
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ret = i2c_transfer(i2c->adapter, xfer, 2);
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if (ret < 0)
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return ret;
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if (ret != 2)
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return -EIO;
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return 0;
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}
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static int wm831x_i2c_probe(struct i2c_client *i2c,
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const struct i2c_device_id *id)
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{
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struct wm831x *wm831x;
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wm831x = kzalloc(sizeof(struct wm831x), GFP_KERNEL);
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if (wm831x == NULL)
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return -ENOMEM;
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i2c_set_clientdata(i2c, wm831x);
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wm831x->dev = &i2c->dev;
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wm831x->control_data = i2c;
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wm831x->read_dev = wm831x_i2c_read_device;
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wm831x->write_dev = wm831x_i2c_write_device;
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return wm831x_device_init(wm831x, id->driver_data, i2c->irq);
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}
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static int wm831x_i2c_remove(struct i2c_client *i2c)
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{
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struct wm831x *wm831x = i2c_get_clientdata(i2c);
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wm831x_device_exit(wm831x);
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return 0;
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}
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static int wm831x_i2c_suspend(struct device *dev)
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{
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struct wm831x *wm831x = dev_get_drvdata(dev);
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return wm831x_device_suspend(wm831x);
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}
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static const struct i2c_device_id wm831x_i2c_id[] = {
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{ "wm8310", WM8310 },
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{ "wm8311", WM8311 },
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{ "wm8312", WM8312 },
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{ "wm8320", WM8320 },
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{ "wm8321", WM8321 },
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{ "wm8325", WM8325 },
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{ "wm8326", WM8326 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, wm831x_i2c_id);
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static const struct dev_pm_ops wm831x_pm_ops = {
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.suspend = wm831x_i2c_suspend,
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};
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static struct i2c_driver wm831x_i2c_driver = {
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.driver = {
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.name = "wm831x",
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.owner = THIS_MODULE,
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.pm = &wm831x_pm_ops,
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},
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.probe = wm831x_i2c_probe,
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.remove = wm831x_i2c_remove,
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.id_table = wm831x_i2c_id,
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};
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static int __init wm831x_i2c_init(void)
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{
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int ret;
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ret = i2c_add_driver(&wm831x_i2c_driver);
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if (ret != 0)
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pr_err("Failed to register wm831x I2C driver: %d\n", ret);
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return ret;
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}
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subsys_initcall(wm831x_i2c_init);
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static void __exit wm831x_i2c_exit(void)
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{
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i2c_del_driver(&wm831x_i2c_driver);
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}
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module_exit(wm831x_i2c_exit);
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