diff options
Diffstat (limited to 'kernel/drivers/staging/most/hdm-i2c')
-rw-r--r-- | kernel/drivers/staging/most/hdm-i2c/Kconfig | 12 | ||||
-rw-r--r-- | kernel/drivers/staging/most/hdm-i2c/Makefile | 3 | ||||
-rw-r--r-- | kernel/drivers/staging/most/hdm-i2c/hdm_i2c.c | 430 |
3 files changed, 445 insertions, 0 deletions
diff --git a/kernel/drivers/staging/most/hdm-i2c/Kconfig b/kernel/drivers/staging/most/hdm-i2c/Kconfig new file mode 100644 index 000000000..6fd798366 --- /dev/null +++ b/kernel/drivers/staging/most/hdm-i2c/Kconfig @@ -0,0 +1,12 @@ +# +# MOST I2C configuration +# + +config HDM_I2C + tristate "I2C HDM" + depends on I2C + ---help--- + Say Y here if you want to connect via I2C to network tranceiver. + + To compile this driver as a module, choose M here: the + module will be called hdm_i2c. diff --git a/kernel/drivers/staging/most/hdm-i2c/Makefile b/kernel/drivers/staging/most/hdm-i2c/Makefile new file mode 100644 index 000000000..03a4a59b1 --- /dev/null +++ b/kernel/drivers/staging/most/hdm-i2c/Makefile @@ -0,0 +1,3 @@ +obj-$(CONFIG_HDM_I2C) += hdm_i2c.o + +ccflags-y += -Idrivers/staging/most/mostcore/ diff --git a/kernel/drivers/staging/most/hdm-i2c/hdm_i2c.c b/kernel/drivers/staging/most/hdm-i2c/hdm_i2c.c new file mode 100644 index 000000000..ba0263bb3 --- /dev/null +++ b/kernel/drivers/staging/most/hdm-i2c/hdm_i2c.c @@ -0,0 +1,430 @@ +/* + * hdm_i2c.c - Hardware Dependent Module for I2C Interface + * + * Copyright (C) 2013-2015, Microchip Technology Germany II GmbH & Co. KG + * + * 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 file is licensed under GPLv2. + */ + +#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/sched.h> +#include <linux/interrupt.h> +#include <linux/err.h> + +#include <mostcore.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) + +/* IRQ / Polling option */ +static bool polling_req; +module_param(polling_req, bool, S_IRUGO); +MODULE_PARM_DESC(polling_req, "Request Polling. Default = 0 (use irq)"); + +/* Polling Rate */ +static int scan_rate = 100; +module_param(scan_rate, int, 0644); +MODULE_PARM_DESC(scan_rate, "Polling rate in times/sec. Default = 100"); + +struct hdm_i2c { + bool is_open[NUM_CHANNELS]; + bool polling_mode; + struct most_interface most_iface; + struct most_channel_capability capabilities[NUM_CHANNELS]; + struct i2c_client *client; + struct rx { + struct delayed_work dwork; + wait_queue_head_t waitq; + struct list_head list; + struct mutex list_mutex; + } rx; + char name[64]; +}; + +#define to_hdm(iface) container_of(iface, struct hdm_i2c, most_iface) + +/** + * configure_channel - called from MOST core to configure a channel + * @iface: interface the channel belongs to + * @channel: 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) +{ + struct hdm_i2c *dev = to_hdm(most_iface); + + BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS); + BUG_ON(dev->is_open[ch_idx]); + + 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) && (dev->polling_mode)) { + schedule_delayed_work(&dev->rx.dwork, + msecs_to_jiffies(MSEC_PER_SEC / 4)); + } + dev->is_open[ch_idx] = true; + + return 0; +} + +/** + * enqueue - called from MOST core to enqueue a buffer for data transfer + * @iface: intended interface + * @channel: 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); + BUG_ON(!dev->is_open[ch_idx]); + + if (ch_idx == CH_RX) { + /* RX */ + mutex_lock(&dev->rx.list_mutex); + list_add_tail(&mbo->list, &dev->rx.list); + mutex_unlock(&dev->rx.list_mutex); + wake_up_interruptible(&dev->rx.waitq); + } 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 + * @iface: pointer to the interface the channel to be poisoned belongs to + * @channel_id: 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); + BUG_ON(!dev->is_open[ch_idx]); + + dev->is_open[ch_idx] = false; + + if (ch_idx == CH_RX) { + mutex_lock(&dev->rx.list_mutex); + while (!list_empty(&dev->rx.list)) { + mbo = list_first_mbo(&dev->rx.list); + list_del(&mbo->list); + mutex_unlock(&dev->rx.list_mutex); + + mbo->processed_length = 0; + mbo->status = MBO_E_CLOSE; + mbo->complete(mbo); + + mutex_lock(&dev->rx.list_mutex); + } + mutex_unlock(&dev->rx.list_mutex); + wake_up_interruptible(&dev->rx.waitq); + } + + return 0; +} + +static void request_netinfo(struct most_interface *most_iface, + int ch_idx) +{ + pr_info("request_netinfo()\n"); +} + +static void do_rx_work(struct hdm_i2c *dev) +{ + struct mbo *mbo; + unsigned char msg[MAX_BUF_SIZE_CONTROL]; + int ret, ch_idx = CH_RX; + 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; + } + + for (;;) { + /* Conditions to wait for: poisoned channel or free buffer + * available for reading + */ + if (wait_event_interruptible(dev->rx.waitq, + !dev->is_open[ch_idx] || + !list_empty(&dev->rx.list))) { + pr_err("wait_event_interruptible() failed\n"); + return; + } + + if (!dev->is_open[ch_idx]) + return; + + mutex_lock(&dev->rx.list_mutex); + + /* list may be empty if poison or remove is called */ + if (!list_empty(&dev->rx.list)) + break; + + mutex_unlock(&dev->rx.list_mutex); + } + + mbo = list_first_mbo(&dev->rx.list); + list_del(&mbo->list); + mutex_unlock(&dev->rx.list_mutex); + + 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); + + do_rx_work(dev); + + if (dev->polling_mode) { + if (dev->is_open[CH_RX]) + schedule_delayed_work(&dev->rx.dwork, + msecs_to_jiffies(MSEC_PER_SEC + / scan_rate)); + } else { + 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); + + 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, const struct i2c_device_id *id) +{ + struct hdm_i2c *dev; + int ret, i; + struct kobject *kobj; + + 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->is_open[i] = false; + 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; + dev->most_iface.request_netinfo = request_netinfo; + + INIT_LIST_HEAD(&dev->rx.list); + mutex_init(&dev->rx.list_mutex); + init_waitqueue_head(&dev->rx.waitq); + + INIT_DELAYED_WORK(&dev->rx.dwork, pending_rx_work); + + dev->client = client; + i2c_set_clientdata(client, dev); + + kobj = most_register_interface(&dev->most_iface); + if (IS_ERR(kobj)) { + pr_err("Failed to register i2c as a MOST interface\n"); + kfree(dev); + return PTR_ERR(kobj); + } + + dev->polling_mode = polling_req || client->irq <= 0; + if (!dev->polling_mode) { + pr_info("Requesting IRQ: %d\n", client->irq); + ret = request_irq(client->irq, most_irq_handler, 0, + client->name, dev); + if (ret) { + pr_info("IRQ request failed: %d, falling back to polling\n", + ret); + dev->polling_mode = true; + } + } + + if (dev->polling_mode) + pr_info("Using polling at rate: %d times/sec\n", scan_rate); + + 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 int i2c_remove(struct i2c_client *client) +{ + struct hdm_i2c *dev = i2c_get_clientdata(client); + int i; + + if (!dev->polling_mode) + free_irq(client->irq, dev); + + most_deregister_interface(&dev->most_iface); + + for (i = 0 ; i < NUM_CHANNELS; i++) + if (dev->is_open[i]) + poison_channel(&dev->most_iface, i); + cancel_delayed_work_sync(&dev->rx.dwork); + kfree(dev); + + return 0; +} + +static const struct i2c_device_id i2c_id[] = { + { "most_i2c", 0 }, + { }, /* 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("Jain Roy Ambi <JainRoy.Ambi@microchip.com>"); +MODULE_AUTHOR("Andrey Shvetsov <andrey.shvetsov@k2l.de>"); +MODULE_DESCRIPTION("I2C Hardware Dependent Module"); +MODULE_LICENSE("GPL"); |