diff options
Diffstat (limited to 'drivers/mfd/htc-i2cpld.c')
| -rw-r--r-- | drivers/mfd/htc-i2cpld.c | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/drivers/mfd/htc-i2cpld.c b/drivers/mfd/htc-i2cpld.c new file mode 100644 index 00000000000..37b9fdab4f3 --- /dev/null +++ b/drivers/mfd/htc-i2cpld.c @@ -0,0 +1,710 @@ +/* + * 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> + +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; + + /* + * 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(unsigned int irq) +{ + struct htcpld_chip *chip = get_irq_chip_data(irq); + chip->irqs_enabled &= ~(1 << (irq - chip->irq_start)); + pr_debug("HTCPLD mask %d %04x\n", irq, chip->irqs_enabled); +} +static void htcpld_unmask(unsigned int irq) +{ + struct htcpld_chip *chip = get_irq_chip_data(irq); + chip->irqs_enabled |= 1 << (irq - chip->irq_start); + pr_debug("HTCPLD unmask %d %04x\n", irq, chip->irqs_enabled); +} + +static int htcpld_set_type(unsigned int irq, unsigned int flags) +{ + struct irq_desc *d = irq_to_desc(irq); + + if (!d) { + pr_err("HTCPLD invalid IRQ: %d\n", irq); + return -EINVAL; + } + + 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; + + d->status &= ~IRQ_TYPE_SENSE_MASK; + d->status |= flags; + + return 0; +} + +static struct irq_chip htcpld_muxed_chip = { + .name = "htcpld", + .mask = htcpld_mask, + .unmask = htcpld_unmask, + .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; + struct irq_desc *desc; + + 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; + int flags; + + irq = chip->irq_start + irqpin; + desc = irq_to_desc(irq); + flags = desc->status; + + /* 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 && (flags & IRQ_TYPE_EDGE_RISING)) || + (oldb && !newb && + (flags & IRQ_TYPE_EDGE_FALLING))) { + pr_debug("fire IRQ %d\n", irqpin); + desc->handle_irq(irq, desc); + } + } + } + + /* + * 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. + */ +void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val) +{ + struct i2c_client *client; + struct htcpld_chip *chip_data; + unsigned long flags; + + chip_data = container_of(chip, struct htcpld_chip, chip_out); + if (!chip_data) + return; + + client = chip_data->client; + if (client == NULL) + 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)); +} + +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); +} + +int htcpld_chip_get(struct gpio_chip *chip, unsigned offset) +{ + struct htcpld_chip *chip_data; + int val = 0; + int is_input = 0; + + /* Try out first */ + chip_data = container_of(chip, struct htcpld_chip, chip_out); + if (!chip_data) { + /* Try in */ + is_input = 1; + chip_data = container_of(chip, struct htcpld_chip, chip_in); + if (!chip_data) + return -EINVAL; + } + + /* Determine if this is an input or output GPIO */ + if (!is_input) + /* Use the output cache */ + val = (chip_data->cache_out >> offset) & 1; + else + /* Use the input cache */ + val = (chip_data->cache_in >> offset) & 1; + + if (val) + return 1; + else + return 0; +} + +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; +} + +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; +} + +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 __devinit htcpld_setup_chip_irq( + 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; + unsigned int irq, irq_end; + int ret = 0; + + /* Get the platform and driver data */ + pdata = dev->platform_data; + htcpld = platform_get_drvdata(pdev); + chip = &htcpld->chip[chip_index]; + plat_chip_data = &pdata->chip[chip_index]; + + /* Setup irq handlers */ + irq_end = chip->irq_start + chip->nirqs; + for (irq = chip->irq_start; irq < irq_end; irq++) { + set_irq_chip(irq, &htcpld_muxed_chip); + set_irq_chip_data(irq, chip); + set_irq_handler(irq, handle_simple_irq); +#ifdef CONFIG_ARM + set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); +#else + set_irq_probe(irq); +#endif + } + + return ret; +} + +static int __devinit 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->platform_data; + 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 == NULL) { + /* 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 __devinit 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 __devinit 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->platform_data; + 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 __devinit 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->platform_data; + htcpld = platform_get_drvdata(pdev); + + /* Setup each chip's output GPIOs */ + htcpld->nchips = pdata->num_chip; + htcpld->chip = kzalloc(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 __devinit 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->platform_data; + if (!pdata) { + dev_warn(dev, "Platform data not found for htcpld core!\n"); + return -ENXIO; + } + + htcpld = kzalloc(sizeof(struct htcpld_data), GFP_KERNEL); + if (!htcpld) + return -ENOMEM; + + /* Find chained irq */ + ret = -EINVAL; + 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); + goto fail; + } 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) + goto fail; + + /* 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; + +fail: + kfree(htcpld); + return ret; +} + +/* 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"); + |