+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/*
- * i2c.c - Hardware Dependent Module for I2C Interface
- *
- * Copyright (C) 2013-2015, Microchip Technology Germany II GmbH & Co. KG
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/i2c.h>
-#include <linux/interrupt.h>
-#include <linux/err.h>
-#include <linux/most.h>
-
-enum { CH_RX, CH_TX, NUM_CHANNELS };
-
-#define MAX_BUFFERS_CONTROL 32
-#define MAX_BUF_SIZE_CONTROL 256
-
-/**
- * list_first_mbo - get the first mbo from a list
- * @ptr: the list head to take the mbo from.
- */
-#define list_first_mbo(ptr) \
- list_first_entry(ptr, struct mbo, list)
-
-static unsigned int polling_rate;
-module_param(polling_rate, uint, 0644);
-MODULE_PARM_DESC(polling_rate, "Polling rate [Hz]. Default = 0 (use IRQ)");
-
-struct hdm_i2c {
- struct most_interface most_iface;
- struct most_channel_capability capabilities[NUM_CHANNELS];
- struct i2c_client *client;
- struct rx {
- struct delayed_work dwork;
- struct list_head list;
- bool int_disabled;
- unsigned int delay;
- } rx;
- char name[64];
-};
-
-static inline struct hdm_i2c *to_hdm(struct most_interface *iface)
-{
- return container_of(iface, struct hdm_i2c, most_iface);
-}
-
-static irqreturn_t most_irq_handler(int, void *);
-static void pending_rx_work(struct work_struct *);
-
-/**
- * configure_channel - called from MOST core to configure a channel
- * @most_iface: interface the channel belongs to
- * @ch_idx: channel to be configured
- * @channel_config: structure that holds the configuration information
- *
- * Return 0 on success, negative on failure.
- *
- * Receives configuration information from MOST core and initialize the
- * corresponding channel.
- */
-static int configure_channel(struct most_interface *most_iface,
- int ch_idx,
- struct most_channel_config *channel_config)
-{
- int ret;
- struct hdm_i2c *dev = to_hdm(most_iface);
- unsigned int delay, pr;
-
- BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS);
-
- if (channel_config->data_type != MOST_CH_CONTROL) {
- pr_err("bad data type for channel %d\n", ch_idx);
- return -EPERM;
- }
-
- if (channel_config->direction != dev->capabilities[ch_idx].direction) {
- pr_err("bad direction for channel %d\n", ch_idx);
- return -EPERM;
- }
-
- if (channel_config->direction == MOST_CH_RX) {
- if (!polling_rate) {
- if (dev->client->irq <= 0) {
- pr_err("bad irq: %d\n", dev->client->irq);
- return -ENOENT;
- }
- dev->rx.int_disabled = false;
- ret = request_irq(dev->client->irq, most_irq_handler, 0,
- dev->client->name, dev);
- if (ret) {
- pr_err("request_irq(%d) failed: %d\n",
- dev->client->irq, ret);
- return ret;
- }
- } else {
- delay = msecs_to_jiffies(MSEC_PER_SEC / polling_rate);
- dev->rx.delay = delay ? delay : 1;
- pr = MSEC_PER_SEC / jiffies_to_msecs(dev->rx.delay);
- pr_info("polling rate is %u Hz\n", pr);
- }
- }
-
- return 0;
-}
-
-/**
- * enqueue - called from MOST core to enqueue a buffer for data transfer
- * @most_iface: intended interface
- * @ch_idx: ID of the channel the buffer is intended for
- * @mbo: pointer to the buffer object
- *
- * Return 0 on success, negative on failure.
- *
- * Transmit the data over I2C if it is a "write" request or push the buffer into
- * list if it is an "read" request
- */
-static int enqueue(struct most_interface *most_iface,
- int ch_idx, struct mbo *mbo)
-{
- struct hdm_i2c *dev = to_hdm(most_iface);
- int ret;
-
- BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS);
-
- if (ch_idx == CH_RX) {
- /* RX */
- if (!polling_rate)
- disable_irq(dev->client->irq);
- cancel_delayed_work_sync(&dev->rx.dwork);
- list_add_tail(&mbo->list, &dev->rx.list);
- if (dev->rx.int_disabled || polling_rate)
- pending_rx_work(&dev->rx.dwork.work);
- if (!polling_rate)
- enable_irq(dev->client->irq);
- } else {
- /* TX */
- ret = i2c_master_send(dev->client, mbo->virt_address,
- mbo->buffer_length);
- if (ret <= 0) {
- mbo->processed_length = 0;
- mbo->status = MBO_E_INVAL;
- } else {
- mbo->processed_length = mbo->buffer_length;
- mbo->status = MBO_SUCCESS;
- }
- mbo->complete(mbo);
- }
-
- return 0;
-}
-
-/**
- * poison_channel - called from MOST core to poison buffers of a channel
- * @most_iface: pointer to the interface the channel to be poisoned belongs to
- * @ch_idx: corresponding channel ID
- *
- * Return 0 on success, negative on failure.
- *
- * If channel direction is RX, complete the buffers in list with
- * status MBO_E_CLOSE
- */
-static int poison_channel(struct most_interface *most_iface,
- int ch_idx)
-{
- struct hdm_i2c *dev = to_hdm(most_iface);
- struct mbo *mbo;
-
- BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS);
-
- if (ch_idx == CH_RX) {
- if (!polling_rate)
- free_irq(dev->client->irq, dev);
- cancel_delayed_work_sync(&dev->rx.dwork);
-
- while (!list_empty(&dev->rx.list)) {
- mbo = list_first_mbo(&dev->rx.list);
- list_del(&mbo->list);
-
- mbo->processed_length = 0;
- mbo->status = MBO_E_CLOSE;
- mbo->complete(mbo);
- }
- }
-
- return 0;
-}
-
-static void do_rx_work(struct hdm_i2c *dev)
-{
- struct mbo *mbo;
- unsigned char msg[MAX_BUF_SIZE_CONTROL];
- int ret;
- u16 pml, data_size;
-
- /* Read PML (2 bytes) */
- ret = i2c_master_recv(dev->client, msg, 2);
- if (ret <= 0) {
- pr_err("Failed to receive PML\n");
- return;
- }
-
- pml = (msg[0] << 8) | msg[1];
- if (!pml)
- return;
-
- data_size = pml + 2;
-
- /* Read the whole message, including PML */
- ret = i2c_master_recv(dev->client, msg, data_size);
- if (ret <= 0) {
- pr_err("Failed to receive a Port Message\n");
- return;
- }
-
- mbo = list_first_mbo(&dev->rx.list);
- list_del(&mbo->list);
-
- mbo->processed_length = min(data_size, mbo->buffer_length);
- memcpy(mbo->virt_address, msg, mbo->processed_length);
- mbo->status = MBO_SUCCESS;
- mbo->complete(mbo);
-}
-
-/**
- * pending_rx_work - Read pending messages through I2C
- * @work: definition of this work item
- *
- * Invoked by the Interrupt Service Routine, most_irq_handler()
- */
-static void pending_rx_work(struct work_struct *work)
-{
- struct hdm_i2c *dev = container_of(work, struct hdm_i2c, rx.dwork.work);
-
- if (list_empty(&dev->rx.list))
- return;
-
- do_rx_work(dev);
-
- if (polling_rate) {
- schedule_delayed_work(&dev->rx.dwork, dev->rx.delay);
- } else {
- dev->rx.int_disabled = false;
- enable_irq(dev->client->irq);
- }
-}
-
-/*
- * most_irq_handler - Interrupt Service Routine
- * @irq: irq number
- * @_dev: private data
- *
- * Schedules a delayed work
- *
- * By default the interrupt line behavior is Active Low. Once an interrupt is
- * generated by the device, until driver clears the interrupt (by reading
- * the PMP message), device keeps the interrupt line in low state. Since i2c
- * read is done in work queue, the interrupt line must be disabled temporarily
- * to avoid ISR being called repeatedly. Re-enable the interrupt in workqueue,
- * after reading the message.
- *
- * Note: If we use the interrupt line in Falling edge mode, there is a
- * possibility to miss interrupts when ISR is getting executed.
- *
- */
-static irqreturn_t most_irq_handler(int irq, void *_dev)
-{
- struct hdm_i2c *dev = _dev;
-
- disable_irq_nosync(irq);
- dev->rx.int_disabled = true;
- schedule_delayed_work(&dev->rx.dwork, 0);
-
- return IRQ_HANDLED;
-}
-
-/*
- * i2c_probe - i2c probe handler
- * @client: i2c client device structure
- * @id: i2c client device id
- *
- * Return 0 on success, negative on failure.
- *
- * Register the i2c client device as a MOST interface
- */
-static int i2c_probe(struct i2c_client *client)
-{
- struct hdm_i2c *dev;
- int ret, i;
-
- dev = kzalloc(sizeof(*dev), GFP_KERNEL);
- if (!dev)
- return -ENOMEM;
-
- /* ID format: i2c-<bus>-<address> */
- snprintf(dev->name, sizeof(dev->name), "i2c-%d-%04x",
- client->adapter->nr, client->addr);
-
- for (i = 0; i < NUM_CHANNELS; i++) {
- dev->capabilities[i].data_type = MOST_CH_CONTROL;
- dev->capabilities[i].num_buffers_packet = MAX_BUFFERS_CONTROL;
- dev->capabilities[i].buffer_size_packet = MAX_BUF_SIZE_CONTROL;
- }
- dev->capabilities[CH_RX].direction = MOST_CH_RX;
- dev->capabilities[CH_RX].name_suffix = "rx";
- dev->capabilities[CH_TX].direction = MOST_CH_TX;
- dev->capabilities[CH_TX].name_suffix = "tx";
-
- dev->most_iface.interface = ITYPE_I2C;
- dev->most_iface.description = dev->name;
- dev->most_iface.num_channels = NUM_CHANNELS;
- dev->most_iface.channel_vector = dev->capabilities;
- dev->most_iface.configure = configure_channel;
- dev->most_iface.enqueue = enqueue;
- dev->most_iface.poison_channel = poison_channel;
-
- INIT_LIST_HEAD(&dev->rx.list);
-
- INIT_DELAYED_WORK(&dev->rx.dwork, pending_rx_work);
-
- dev->client = client;
- i2c_set_clientdata(client, dev);
-
- ret = most_register_interface(&dev->most_iface);
- if (ret) {
- pr_err("Failed to register i2c as a MOST interface\n");
- kfree(dev);
- return ret;
- }
-
- return 0;
-}
-
-/*
- * i2c_remove - i2c remove handler
- * @client: i2c client device structure
- *
- * Return 0 on success.
- *
- * Unregister the i2c client device as a MOST interface
- */
-static void i2c_remove(struct i2c_client *client)
-{
- struct hdm_i2c *dev = i2c_get_clientdata(client);
-
- most_deregister_interface(&dev->most_iface);
- kfree(dev);
-}
-
-static const struct i2c_device_id i2c_id[] = {
- { "most_i2c" },
- { } /* Terminating entry */
-};
-
-MODULE_DEVICE_TABLE(i2c, i2c_id);
-
-static struct i2c_driver i2c_driver = {
- .driver = {
- .name = "hdm_i2c",
- },
- .probe = i2c_probe,
- .remove = i2c_remove,
- .id_table = i2c_id,
-};
-
-module_i2c_driver(i2c_driver);
-
-MODULE_AUTHOR("Andrey Shvetsov <andrey.shvetsov@k2l.de>");
-MODULE_DESCRIPTION("I2C Hardware Dependent Module");
-MODULE_LICENSE("GPL");
projects / thirdparty / linux.git / commitdiff
