/*
* htc-i2cpld.c
* Chip driver for an unknown CPLD chip found on omap850 HTC devices like
* the HTC Wizard and HTC Herald.
* The cpld is located on the i2c bus and acts as an input/output GPIO
* extender.
*
* Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
*
* Based on work done in the linwizard project
* Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/spinlock.h>
#include <linux/htcpld.h>
#include <linux/gpio.h>
#include <linux/slab.h>
struct htcpld_chip {
spinlock_t lock;
/* chip info */
u8 reset;
u8 addr;
struct device *dev;
struct i2c_client *client;
/* Output details */
u8 cache_out;
struct gpio_chip chip_out;
/* Input details */
u8 cache_in;
struct gpio_chip chip_in;
u16 irqs_enabled;
uint irq_start;
int nirqs;
unsigned int flow_type;
/*
* Work structure to allow for setting values outside of any
* possible interrupt context
*/
struct work_struct set_val_work;
};
struct htcpld_data {
/* irq info */
u16 irqs_enabled;
uint irq_start;
int nirqs;
uint chained_irq;
unsigned int int_reset_gpio_hi;
unsigned int int_reset_gpio_lo;
/* htcpld info */
struct htcpld_chip *chip;
unsigned int nchips;
};
/* There does not appear to be a way to proactively mask interrupts
* on the htcpld chip itself. So, we simply ignore interrupts that
* aren't desired. */
static void htcpld_mask(struct irq_data *data)
{
struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
}
static void htcpld_unmask(struct irq_data *data)
{
struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
}
static int htcpld_set_type(struct irq_data *data, unsigned int flags)
{
struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
if (flags & ~IRQ_TYPE_SENSE_MASK)
return -EINVAL;
/* We only allow edge triggering */
if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
return -EINVAL;
chip->flow_type = flags;
return 0;
}
static struct irq_chip htcpld_muxed_chip = {
.name = "htcpld",
.irq_mask = htcpld_mask,
.irq_unmask = htcpld_unmask,
.irq_set_type = htcpld_set_type,
};
/* To properly dispatch IRQ events, we need to read from the
* chip. This is an I2C action that could possibly sleep
* (which is bad in interrupt context) -- so we use a threaded
* interrupt handler to get around that.
*/
static irqreturn_t htcpld_handler(int irq, void *dev)
{
struct htcpld_data *htcpld = dev;
unsigned int i;
unsigned long flags;
int irqpin;
if (!htcpld) {
pr_debug("htcpld is null in ISR\n");
return IRQ_HANDLED;
}
/*
* For each chip, do a read of the chip and trigger any interrupts
* desired. The interrupts will be triggered from LSB to MSB (i.e.
* bit 0 first, then bit 1, etc.)
*
* For chips that have no interrupt range specified, just skip 'em.
*/
for (i = 0; i < htcpld->nchips; i++) {
struct htcpld_chip *chip = &htcpld->chip[i];
struct i2c_client *client;
int val;
unsigned long uval, old_val;
if (!chip) {
pr_debug("chip %d is null in ISR\n", i);
continue;
}
if (chip->nirqs == 0)
continue;
client = chip->client;
if (!client) {
pr_debug("client %d is null in ISR\n", i);
continue;
}
/* Scan the chip */
val = i2c_smbus_read_byte_data(client, chip->cache_out);
if (val < 0) {
/* Throw a warning and skip this chip */
dev_warn(chip->dev, "Unable to read from chip: %d\n",
val);
continue;
}
uval = (unsigned long)val;
spin_lock_irqsave(&chip->lock, flags);
/* Save away the old value so we can compare it */
old_val = chip->cache_in;
/* Write the new value */
chip->cache_in = uval;
spin_unlock_irqrestore(&chip->lock, flags);
/*
* For each bit in the data (starting at bit 0), trigger
* associated interrupts.
*/
for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
unsigned oldb, newb, type = chip->flow_type;
irq = chip->irq_start + irqpin;
/* Run the IRQ handler, but only if the bit value
* changed, and the proper flags are set */
oldb = (old_val >> irqpin) & 1;
newb = (uval >> irqpin) & 1;
if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
(oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
pr_debug("fire IRQ %d\n", irqpin);
generic_handle_irq(irq);
}
}
}
/*
* In order to continue receiving interrupts, the int_reset_gpio must
* be asserted.
*/
if (htcpld->int_reset_gpio_hi)
gpio_set_value(htcpld->int_reset_gpio_hi, 1);
if (htcpld->int_reset_gpio_lo)
gpio_set_value(htcpld->int_reset_gpio_lo, 0);
return IRQ_HANDLED;
}
/*
* The GPIO set routines can be called from interrupt context, especially if,
* for example they're attached to the led-gpio framework and a trigger is
* enabled. As such, we declared work above in the htcpld_chip structure,
* and that work is scheduled in the set routine. The kernel can then run
* the I2C functions, which will sleep, in process context.
*/
static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
{
struct i2c_client *client;
struct htcpld_chip *chip_data =
container_of(chip, struct htcpld_chip, chip_out);
unsigned long flags;
client = chip_data->client;
if (!client)
return;
spin_lock_irqsave(&chip_data->lock, flags);
if (val)
chip_data->cache_out |= (1 << offset);
else
chip_data->cache_out &= ~(1 << offset);
spin_unlock_irqrestore(&chip_data->lock, flags);
schedule_work(&(chip_data->set_val_work));
}
static void htcpld_chip_set_ni(struct work_struct *work)
{
struct htcpld_chip *chip_data;
struct i2c_client *client;
chip_data = container_of(work, struct htcpld_chip, set_val_work);
client = chip_data->client;
i2c_smbus_read_byte_data(client, chip_data->cache_out);
}
static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
{
struct htcpld_chip *chip_data;
u8 cache;
if (!strncmp(chip->label, "htcpld-out", 10)) {
chip_data = container_of(chip, struct htcpld_chip, chip_out);
cache = chip_data->cache_out;
} else if (!strncmp(chip->label, "htcpld-in", 9)) {
chip_data = container_of(chip, struct htcpld_chip, chip_in);
cache = chip_data->cache_in;
} else
return -EINVAL;
return (cache >> offset) & 1;
}
static int htcpld_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
htcpld_chip_set(chip, offset, value);
return 0;
}
static int htcpld_direction_input(struct gpio_chip *chip,
unsigned offset)
{
/*
* No-op: this function can only be called on the input chip.
* We do however make sure the offset is within range.
*/
return (offset < chip->ngpio) ? 0 : -EINVAL;
}
static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
{
struct htcpld_chip *chip_data;
chip_data = container_of(chip, struct htcpld_chip, chip_in);
if (offset < chip_data->nirqs)
return chip_data->irq_start + offset;
else
return -EINVAL;
}
static void htcpld_chip_reset(struct i2c_client *client)
{
struct htcpld_chip *chip_data = i2c_get_clientdata(client);
if (!chip_data)
return;
i2c_smbus_read_byte_data(
client, (chip_data->cache_out = chip_data->reset));
}
static int htcpld_setup_chip_irq(
struct platform_device *pdev,
int chip_index)
{
struct htcpld_data *htcpld;
struct htcpld_chip *chip;
unsigned int irq, irq_end;
int ret = 0;
/* Get the platform and driver data */
htcpld = platform_get_drvdata(pdev);
chip = &htcpld->chip[chip_index];
/* Setup irq handlers */
irq_end = chip->irq_start + chip->nirqs;
for (irq = chip->irq_start; irq < irq_end; irq++) {
irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
handle_simple_irq);
irq_set_chip_data(irq, chip);
#ifdef CONFIG_ARM
set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
#else
irq_set_probe(irq);
#endif
}
return ret;
}
static int htcpld_register_chip_i2c(
struct platform_device *pdev,
int chip_index)
{
struct htcpld_data *htcpld;
struct device *dev = &pdev->dev;
struct htcpld_core_platform_data *pdata;
struct htcpld_chip *chip;
struct htcpld_chip_platform_data *plat_chip_data;
struct i2c_adapter *adapter;
struct i2c_client *client;
struct i2c_board_info info;
/* Get the platform and driver data */
pdata = dev_get_platdata(dev);
htcpld = platform_get_drvdata(pdev);
chip = &htcpld->chip[chip_index];
plat_chip_data = &pdata->chip[chip_index];
adapter = i2c_get_adapter(pdata->i2c_adapter_id);
if (!adapter) {
/* Eek, no such I2C adapter! Bail out. */
dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
plat_chip_data->addr, pdata->i2c_adapter_id);
return -ENODEV;
}
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
dev_warn(dev, "i2c adapter %d non-functional\n",
pdata->i2c_adapter_id);
return -EINVAL;
}
memset(&info, 0, sizeof(struct i2c_board_info));
info.addr = plat_chip_data->addr;
strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
info.platform_data = chip;
/* Add the I2C device. This calls the probe() function. */
client = i2c_new_device(adapter, &info);
if (!client) {
/* I2C device registration failed, contineu with the next */
dev_warn(dev, "Unable to add I2C device for 0x%x\n",
plat_chip_data->addr);
return -ENODEV;
}
i2c_set_clientdata(client, chip);
snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%d", client->addr);
chip->client = client;
/* Reset the chip */
htcpld_chip_reset(client);
chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
return 0;
}
static void htcpld_unregister_chip_i2c(
struct platform_device *pdev,
int chip_index)
{
struct htcpld_data *htcpld;
struct htcpld_chip *chip;
/* Get the platform and driver data */
htcpld = platform_get_drvdata(pdev);
chip = &htcpld->chip[chip_index];
if (chip->client)
i2c_unregister_device(chip->client);
}
static int htcpld_register_chip_gpio(
struct platform_device *pdev,
int chip_index)
{
struct htcpld_data *htcpld;
struct device *dev = &pdev->dev;
struct htcpld_core_platform_data *pdata;
struct htcpld_chip *chip;
struct htcpld_chip_platform_data *plat_chip_data;
struct gpio_chip *gpio_chip;
int ret = 0;
/* Get the platform and driver data */
pdata = dev_get_platdata(dev);
htcpld = platform_get_drvdata(pdev);
chip = &htcpld->chip[chip_index];
plat_chip_data = &pdata->chip[chip_index];
/* Setup the GPIO chips */
gpio_chip = &(chip->chip_out);
gpio_chip->label = "htcpld-out";
gpio_chip->dev = dev;
gpio_chip->owner = THIS_MODULE;
gpio_chip->get = htcpld_chip_get;
gpio_chip->set = htcpld_chip_set;
gpio_chip->direction_input = NULL;
gpio_chip->direction_output = htcpld_direction_output;
gpio_chip->base = plat_chip_data->gpio_out_base;
gpio_chip->ngpio = plat_chip_data->num_gpios;
gpio_chip = &(chip->chip_in);
gpio_chip->label = "htcpld-in";
gpio_chip->dev = dev;
gpio_chip->owner = THIS_MODULE;
gpio_chip->get = htcpld_chip_get;
gpio_chip->set = NULL;
gpio_chip->direction_input = htcpld_direction_input;
gpio_chip->direction_output = NULL;
gpio_chip->to_irq = htcpld_chip_to_irq;
gpio_chip->base = plat_chip_data->gpio_in_base;
gpio_chip->ngpio = plat_chip_data->num_gpios;
/* Add the GPIO chips */
ret = gpiochip_add(&(chip->chip_out));
if (ret) {
dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
plat_chip_data->addr, ret);
return ret;
}
ret = gpiochip_add(&(chip->chip_in));
if (ret) {
int error;
dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
plat_chip_data->addr, ret);
error = gpiochip_remove(&(chip->chip_out));
if (error)
dev_warn(dev, "Error while trying to unregister gpio chip: %d\n", error);
return ret;
}
return 0;
}
static int htcpld_setup_chips(struct platform_device *pdev)
{
struct htcpld_data *htcpld;
struct device *dev = &pdev->dev;
struct htcpld_core_platform_data *pdata;
int i;
/* Get the platform and driver data */
pdata = dev_get_platdata(dev);
htcpld = platform_get_drvdata(pdev);
/* Setup each chip's output GPIOs */
htcpld->nchips = pdata->num_chip;
htcpld->chip = devm_kzalloc(dev, sizeof(struct htcpld_chip) * htcpld->nchips,
GFP_KERNEL);
if (!htcpld->chip) {
dev_warn(dev, "Unable to allocate memory for chips\n");
return -ENOMEM;
}
/* Add the chips as best we can */
for (i = 0; i < htcpld->nchips; i++) {
int ret;
/* Setup the HTCPLD chips */
htcpld->chip[i].reset = pdata->chip[i].reset;
htcpld->chip[i].cache_out = pdata->chip[i].reset;
htcpld->chip[i].cache_in = 0;
htcpld->chip[i].dev = dev;
htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
spin_lock_init(&(htcpld->chip[i].lock));
/* Setup the interrupts for the chip */
if (htcpld->chained_irq) {
ret = htcpld_setup_chip_irq(pdev, i);
if (ret)
continue;
}
/* Register the chip with I2C */
ret = htcpld_register_chip_i2c(pdev, i);
if (ret)
continue;
/* Register the chips with the GPIO subsystem */
ret = htcpld_register_chip_gpio(pdev, i);
if (ret) {
/* Unregister the chip from i2c and continue */
htcpld_unregister_chip_i2c(pdev, i);
continue;
}
dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
}
return 0;
}
static int htcpld_core_probe(struct platform_device *pdev)
{
struct htcpld_data *htcpld;
struct device *dev = &pdev->dev;
struct htcpld_core_platform_data *pdata;
struct resource *res;
int ret = 0;
if (!dev)
return -ENODEV;
pdata = dev_get_platdata(dev);
if (!pdata) {
dev_warn(dev, "Platform data not found for htcpld core!\n");
return -ENXIO;
}
htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
if (!htcpld)
return -ENOMEM;
/* Find chained irq */
res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (res) {
int flags;
htcpld->chained_irq = res->start;
/* Setup the chained interrupt handler */
flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
ret = request_threaded_irq(htcpld->chained_irq,
NULL, htcpld_handler,
flags, pdev->name, htcpld);
if (ret) {
dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
return ret;
} else
device_init_wakeup(dev, 0);
}
/* Set the driver data */
platform_set_drvdata(pdev, htcpld);
/* Setup the htcpld chips */
ret = htcpld_setup_chips(pdev);
if (ret)
return ret;
/* Request the GPIO(s) for the int reset and set them up */
if (pdata->int_reset_gpio_hi) {
ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
if (ret) {
/*
* If it failed, that sucks, but we can probably
* continue on without it.
*/
dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
htcpld->int_reset_gpio_hi = 0;
} else {
htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
gpio_set_value(htcpld->int_reset_gpio_hi, 1);
}
}
if (pdata->int_reset_gpio_lo) {
ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
if (ret) {
/*
* If it failed, that sucks, but we can probably
* continue on without it.
*/
dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
htcpld->int_reset_gpio_lo = 0;
} else {
htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
gpio_set_value(htcpld->int_reset_gpio_lo, 0);
}
}
dev_info(dev, "Initialized successfully\n");
return 0;
}
/* The I2C Driver -- used internally */
static const struct i2c_device_id htcpld_chip_id[] = {
{ "htcpld-chip", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, htcpld_chip_id);
static struct i2c_driver htcpld_chip_driver = {
.driver = {
.name = "htcpld-chip",
},
.id_table = htcpld_chip_id,
};
/* The Core Driver */
static struct platform_driver htcpld_core_driver = {
.driver = {
.name = "i2c-htcpld",
},
};
static int __init htcpld_core_init(void)
{
int ret;
/* Register the I2C Chip driver */
ret = i2c_add_driver(&htcpld_chip_driver);
if (ret)
return ret;
/* Probe for our chips */
return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
}
static void __exit htcpld_core_exit(void)
{
i2c_del_driver(&htcpld_chip_driver);
platform_driver_unregister(&htcpld_core_driver);
}
module_init(htcpld_core_init);
module_exit(htcpld_core_exit);
MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>");
MODULE_DESCRIPTION("I2C HTC PLD Driver");
MODULE_LICENSE("GPL");
