// SPDX-License-Identifier: GPL-2.0-or-later /* * 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> */ #include <linux/kernel.h> #include <linux/init.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 = gpiochip_get_data(chip); 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 = gpiochip_get_data(chip); u8 cache; if (!strncmp(chip->label, "htcpld-out", 10)) { cache = chip_data->cache_out; } else if (!strncmp(chip->label, "htcpld-in", 9)) { 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 = gpiochip_get_data(chip); 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; /* 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); irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE); } return 0; } 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); i2c_put_adapter(adapter); 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_client_device(adapter, &info); if (IS_ERR(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); i2c_put_adapter(adapter); return PTR_ERR(client); } i2c_set_clientdata(client, chip); snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", 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]; 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->parent = 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->parent = 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_data(&(chip->chip_out), chip); 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_data(&(chip->chip_in), chip); if (ret) { dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n", plat_chip_data->addr, ret); gpiochip_remove(&(chip->chip_out)); 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_kcalloc(dev, htcpld->nchips, sizeof(struct htcpld_chip), GFP_KERNEL); if (!htcpld->chip) 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 | IRQF_ONESHOT; 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 }, { } }; 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); } device_initcall(htcpld_core_init);