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Based on 3 normalized pattern(s): 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 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 [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] 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 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 [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
209 lines
5.1 KiB
C
209 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* i2c-smbus.c - SMBus extensions to the I2C protocol
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*
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* Copyright (C) 2008 David Brownell
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* Copyright (C) 2010 Jean Delvare <jdelvare@suse.de>
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*/
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#include <linux/device.h>
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#include <linux/i2c.h>
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#include <linux/i2c-smbus.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of_irq.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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struct i2c_smbus_alert {
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struct work_struct alert;
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struct i2c_client *ara; /* Alert response address */
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};
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struct alert_data {
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unsigned short addr;
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enum i2c_alert_protocol type;
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unsigned int data;
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};
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/* If this is the alerting device, notify its driver */
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static int smbus_do_alert(struct device *dev, void *addrp)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct alert_data *data = addrp;
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struct i2c_driver *driver;
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if (!client || client->addr != data->addr)
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return 0;
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if (client->flags & I2C_CLIENT_TEN)
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return 0;
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/*
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* Drivers should either disable alerts, or provide at least
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* a minimal handler. Lock so the driver won't change.
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*/
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device_lock(dev);
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if (client->dev.driver) {
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driver = to_i2c_driver(client->dev.driver);
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if (driver->alert)
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driver->alert(client, data->type, data->data);
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else
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dev_warn(&client->dev, "no driver alert()!\n");
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} else
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dev_dbg(&client->dev, "alert with no driver\n");
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device_unlock(dev);
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/* Stop iterating after we find the device */
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return -EBUSY;
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}
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/*
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* The alert IRQ handler needs to hand work off to a task which can issue
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* SMBus calls, because those sleeping calls can't be made in IRQ context.
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*/
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static irqreturn_t smbus_alert(int irq, void *d)
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{
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struct i2c_smbus_alert *alert = d;
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struct i2c_client *ara;
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unsigned short prev_addr = 0; /* Not a valid address */
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ara = alert->ara;
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for (;;) {
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s32 status;
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struct alert_data data;
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/*
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* Devices with pending alerts reply in address order, low
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* to high, because of slave transmit arbitration. After
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* responding, an SMBus device stops asserting SMBALERT#.
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*
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* Note that SMBus 2.0 reserves 10-bit addresses for future
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* use. We neither handle them, nor try to use PEC here.
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*/
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status = i2c_smbus_read_byte(ara);
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if (status < 0)
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break;
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data.data = status & 1;
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data.addr = status >> 1;
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data.type = I2C_PROTOCOL_SMBUS_ALERT;
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if (data.addr == prev_addr) {
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dev_warn(&ara->dev, "Duplicate SMBALERT# from dev "
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"0x%02x, skipping\n", data.addr);
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break;
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}
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dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n",
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data.addr, data.data);
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/* Notify driver for the device which issued the alert */
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device_for_each_child(&ara->adapter->dev, &data,
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smbus_do_alert);
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prev_addr = data.addr;
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}
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return IRQ_HANDLED;
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}
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static void smbalert_work(struct work_struct *work)
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{
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struct i2c_smbus_alert *alert;
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alert = container_of(work, struct i2c_smbus_alert, alert);
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smbus_alert(0, alert);
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}
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/* Setup SMBALERT# infrastructure */
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static int smbalert_probe(struct i2c_client *ara,
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const struct i2c_device_id *id)
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{
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struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev);
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struct i2c_smbus_alert *alert;
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struct i2c_adapter *adapter = ara->adapter;
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int res, irq;
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alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
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GFP_KERNEL);
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if (!alert)
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return -ENOMEM;
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if (setup) {
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irq = setup->irq;
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} else {
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irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert");
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if (irq <= 0)
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return irq;
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}
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INIT_WORK(&alert->alert, smbalert_work);
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alert->ara = ara;
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if (irq > 0) {
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res = devm_request_threaded_irq(&ara->dev, irq,
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NULL, smbus_alert,
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IRQF_SHARED | IRQF_ONESHOT,
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"smbus_alert", alert);
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if (res)
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return res;
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}
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i2c_set_clientdata(ara, alert);
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dev_info(&adapter->dev, "supports SMBALERT#\n");
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return 0;
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}
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/* IRQ and memory resources are managed so they are freed automatically */
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static int smbalert_remove(struct i2c_client *ara)
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{
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struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
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cancel_work_sync(&alert->alert);
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return 0;
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}
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static const struct i2c_device_id smbalert_ids[] = {
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{ "smbus_alert", 0 },
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{ /* LIST END */ }
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};
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MODULE_DEVICE_TABLE(i2c, smbalert_ids);
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static struct i2c_driver smbalert_driver = {
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.driver = {
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.name = "smbus_alert",
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},
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.probe = smbalert_probe,
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.remove = smbalert_remove,
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.id_table = smbalert_ids,
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};
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/**
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* i2c_handle_smbus_alert - Handle an SMBus alert
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* @ara: the ARA client on the relevant adapter
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* Context: can't sleep
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*
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* Helper function to be called from an I2C bus driver's interrupt
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* handler. It will schedule the alert work, in turn calling the
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* corresponding I2C device driver's alert function.
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*
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* It is assumed that ara is a valid i2c client previously returned by
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* i2c_setup_smbus_alert().
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*/
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int i2c_handle_smbus_alert(struct i2c_client *ara)
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{
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struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
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return schedule_work(&alert->alert);
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}
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EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
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module_i2c_driver(smbalert_driver);
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MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
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MODULE_DESCRIPTION("SMBus protocol extensions support");
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MODULE_LICENSE("GPL");
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