diff options
Diffstat (limited to 'drivers/gpio/gpio-dln2.c')
| -rw-r--r-- | drivers/gpio/gpio-dln2.c | 553 |
1 files changed, 553 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-dln2.c b/drivers/gpio/gpio-dln2.c new file mode 100644 index 000000000000..978b51eae2ec --- /dev/null +++ b/drivers/gpio/gpio-dln2.c @@ -0,0 +1,553 @@ +/* + * Driver for the Diolan DLN-2 USB-GPIO adapter + * + * Copyright (c) 2014 Intel Corporation + * + * 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, version 2. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/irqdomain.h> +#include <linux/irq.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/gpio.h> +#include <linux/gpio/driver.h> +#include <linux/platform_device.h> +#include <linux/mfd/dln2.h> + +#define DLN2_GPIO_ID 0x01 + +#define DLN2_GPIO_GET_PIN_COUNT DLN2_CMD(0x01, DLN2_GPIO_ID) +#define DLN2_GPIO_SET_DEBOUNCE DLN2_CMD(0x04, DLN2_GPIO_ID) +#define DLN2_GPIO_GET_DEBOUNCE DLN2_CMD(0x05, DLN2_GPIO_ID) +#define DLN2_GPIO_PORT_GET_VAL DLN2_CMD(0x06, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_GET_VAL DLN2_CMD(0x0B, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_SET_OUT_VAL DLN2_CMD(0x0C, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_GET_OUT_VAL DLN2_CMD(0x0D, DLN2_GPIO_ID) +#define DLN2_GPIO_CONDITION_MET_EV DLN2_CMD(0x0F, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_ENABLE DLN2_CMD(0x10, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_DISABLE DLN2_CMD(0x11, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_SET_DIRECTION DLN2_CMD(0x13, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_GET_DIRECTION DLN2_CMD(0x14, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_SET_EVENT_CFG DLN2_CMD(0x1E, DLN2_GPIO_ID) +#define DLN2_GPIO_PIN_GET_EVENT_CFG DLN2_CMD(0x1F, DLN2_GPIO_ID) + +#define DLN2_GPIO_EVENT_NONE 0 +#define DLN2_GPIO_EVENT_CHANGE 1 +#define DLN2_GPIO_EVENT_LVL_HIGH 2 +#define DLN2_GPIO_EVENT_LVL_LOW 3 +#define DLN2_GPIO_EVENT_CHANGE_RISING 0x11 +#define DLN2_GPIO_EVENT_CHANGE_FALLING 0x21 +#define DLN2_GPIO_EVENT_MASK 0x0F + +#define DLN2_GPIO_MAX_PINS 32 + +struct dln2_irq_work { + struct work_struct work; + struct dln2_gpio *dln2; + int pin; + int type; +}; + +struct dln2_gpio { + struct platform_device *pdev; + struct gpio_chip gpio; + + /* + * Cache pin direction to save us one transfer, since the hardware has + * separate commands to read the in and out values. + */ + DECLARE_BITMAP(output_enabled, DLN2_GPIO_MAX_PINS); + + DECLARE_BITMAP(irqs_masked, DLN2_GPIO_MAX_PINS); + DECLARE_BITMAP(irqs_enabled, DLN2_GPIO_MAX_PINS); + DECLARE_BITMAP(irqs_pending, DLN2_GPIO_MAX_PINS); + struct dln2_irq_work *irq_work; +}; + +struct dln2_gpio_pin { + __le16 pin; +}; + +struct dln2_gpio_pin_val { + __le16 pin __packed; + u8 value; +}; + +static int dln2_gpio_get_pin_count(struct platform_device *pdev) +{ + int ret; + __le16 count; + int len = sizeof(count); + + ret = dln2_transfer_rx(pdev, DLN2_GPIO_GET_PIN_COUNT, &count, &len); + if (ret < 0) + return ret; + if (len < sizeof(count)) + return -EPROTO; + + return le16_to_cpu(count); +} + +static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin) +{ + struct dln2_gpio_pin req = { + .pin = cpu_to_le16(pin), + }; + + return dln2_transfer_tx(dln2->pdev, cmd, &req, sizeof(req)); +} + +static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin) +{ + int ret; + struct dln2_gpio_pin req = { + .pin = cpu_to_le16(pin), + }; + struct dln2_gpio_pin_val rsp; + int len = sizeof(rsp); + + ret = dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), &rsp, &len); + if (ret < 0) + return ret; + if (len < sizeof(rsp) || req.pin != rsp.pin) + return -EPROTO; + + return rsp.value; +} + +static int dln2_gpio_pin_get_in_val(struct dln2_gpio *dln2, unsigned int pin) +{ + int ret; + + ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_VAL, pin); + if (ret < 0) + return ret; + return !!ret; +} + +static int dln2_gpio_pin_get_out_val(struct dln2_gpio *dln2, unsigned int pin) +{ + int ret; + + ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_OUT_VAL, pin); + if (ret < 0) + return ret; + return !!ret; +} + +static void dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2, + unsigned int pin, int value) +{ + struct dln2_gpio_pin_val req = { + .pin = cpu_to_le16(pin), + .value = value, + }; + + dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req, + sizeof(req)); +} + +#define DLN2_GPIO_DIRECTION_IN 0 +#define DLN2_GPIO_DIRECTION_OUT 1 + +static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + struct dln2_gpio_pin req = { + .pin = cpu_to_le16(offset), + }; + struct dln2_gpio_pin_val rsp; + int len = sizeof(rsp); + int ret; + + ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset); + if (ret < 0) + return ret; + + /* cache the pin direction */ + ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION, + &req, sizeof(req), &rsp, &len); + if (ret < 0) + return ret; + if (len < sizeof(rsp) || req.pin != rsp.pin) { + ret = -EPROTO; + goto out_disable; + } + + switch (rsp.value) { + case DLN2_GPIO_DIRECTION_IN: + clear_bit(offset, dln2->output_enabled); + return 0; + case DLN2_GPIO_DIRECTION_OUT: + set_bit(offset, dln2->output_enabled); + return 0; + default: + ret = -EPROTO; + goto out_disable; + } + +out_disable: + dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset); + return ret; +} + +static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + + dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset); +} + +static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + + if (test_bit(offset, dln2->output_enabled)) + return GPIOF_DIR_OUT; + + return GPIOF_DIR_IN; +} + +static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + int dir; + + dir = dln2_gpio_get_direction(chip, offset); + if (dir < 0) + return dir; + + if (dir == GPIOF_DIR_IN) + return dln2_gpio_pin_get_in_val(dln2, offset); + + return dln2_gpio_pin_get_out_val(dln2, offset); +} + +static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + + dln2_gpio_pin_set_out_val(dln2, offset, value); +} + +static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset, + unsigned dir) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + struct dln2_gpio_pin_val req = { + .pin = cpu_to_le16(offset), + .value = dir, + }; + int ret; + + ret = dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_DIRECTION, + &req, sizeof(req)); + if (ret < 0) + return ret; + + if (dir == DLN2_GPIO_DIRECTION_OUT) + set_bit(offset, dln2->output_enabled); + else + clear_bit(offset, dln2->output_enabled); + + return ret; +} + +static int dln2_gpio_direction_input(struct gpio_chip *chip, unsigned offset) +{ + return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_IN); +} + +static int dln2_gpio_direction_output(struct gpio_chip *chip, unsigned offset, + int value) +{ + return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT); +} + +static int dln2_gpio_set_debounce(struct gpio_chip *chip, unsigned offset, + unsigned debounce) +{ + struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio); + __le32 duration = cpu_to_le32(debounce); + + return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE, + &duration, sizeof(duration)); +} + +static int dln2_gpio_set_event_cfg(struct dln2_gpio *dln2, unsigned pin, + unsigned type, unsigned period) +{ + struct { + __le16 pin; + u8 type; + __le16 period; + } __packed req = { + .pin = cpu_to_le16(pin), + .type = type, + .period = cpu_to_le16(period), + }; + + return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_EVENT_CFG, + &req, sizeof(req)); +} + +static void dln2_irq_work(struct work_struct *w) +{ + struct dln2_irq_work *iw = container_of(w, struct dln2_irq_work, work); + struct dln2_gpio *dln2 = iw->dln2; + u8 type = iw->type & DLN2_GPIO_EVENT_MASK; + + if (test_bit(iw->pin, dln2->irqs_enabled)) + dln2_gpio_set_event_cfg(dln2, iw->pin, type, 0); + else + dln2_gpio_set_event_cfg(dln2, iw->pin, DLN2_GPIO_EVENT_NONE, 0); +} + +static void dln2_irq_enable(struct irq_data *irqd) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd); + struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio); + int pin = irqd_to_hwirq(irqd); + + set_bit(pin, dln2->irqs_enabled); + schedule_work(&dln2->irq_work[pin].work); +} + +static void dln2_irq_disable(struct irq_data *irqd) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd); + struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio); + int pin = irqd_to_hwirq(irqd); + + clear_bit(pin, dln2->irqs_enabled); + schedule_work(&dln2->irq_work[pin].work); +} + +static void dln2_irq_mask(struct irq_data *irqd) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd); + struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio); + int pin = irqd_to_hwirq(irqd); + + set_bit(pin, dln2->irqs_masked); +} + +static void dln2_irq_unmask(struct irq_data *irqd) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd); + struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio); + struct device *dev = dln2->gpio.dev; + int pin = irqd_to_hwirq(irqd); + + if (test_and_clear_bit(pin, dln2->irqs_pending)) { + int irq; + + irq = irq_find_mapping(dln2->gpio.irqdomain, pin); + if (!irq) { + dev_err(dev, "pin %d not mapped to IRQ\n", pin); + return; + } + + generic_handle_irq(irq); + } +} + +static int dln2_irq_set_type(struct irq_data *irqd, unsigned type) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd); + struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio); + int pin = irqd_to_hwirq(irqd); + + switch (type) { + case IRQ_TYPE_LEVEL_HIGH: + dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_HIGH; + break; + case IRQ_TYPE_LEVEL_LOW: + dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_LOW; + break; + case IRQ_TYPE_EDGE_BOTH: + dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE; + break; + case IRQ_TYPE_EDGE_RISING: + dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_RISING; + break; + case IRQ_TYPE_EDGE_FALLING: + dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_FALLING; + break; + default: + return -EINVAL; + } + + return 0; +} + +static struct irq_chip dln2_gpio_irqchip = { + .name = "dln2-irq", + .irq_enable = dln2_irq_enable, + .irq_disable = dln2_irq_disable, + .irq_mask = dln2_irq_mask, + .irq_unmask = dln2_irq_unmask, + .irq_set_type = dln2_irq_set_type, +}; + +static void dln2_gpio_event(struct platform_device *pdev, u16 echo, + const void *data, int len) +{ + int pin, irq; + const struct { + __le16 count; + __u8 type; + __le16 pin; + __u8 value; + } __packed *event = data; + struct dln2_gpio *dln2 = platform_get_drvdata(pdev); + + if (len < sizeof(*event)) { + dev_err(dln2->gpio.dev, "short event message\n"); + return; + } + + pin = le16_to_cpu(event->pin); + if (pin >= dln2->gpio.ngpio) { + dev_err(dln2->gpio.dev, "out of bounds pin %d\n", pin); + return; + } + + irq = irq_find_mapping(dln2->gpio.irqdomain, pin); + if (!irq) { + dev_err(dln2->gpio.dev, "pin %d not mapped to IRQ\n", pin); + return; + } + + if (!test_bit(pin, dln2->irqs_enabled)) + return; + if (test_bit(pin, dln2->irqs_masked)) { + set_bit(pin, dln2->irqs_pending); + return; + } + + switch (dln2->irq_work[pin].type) { + case DLN2_GPIO_EVENT_CHANGE_RISING: + if (event->value) + generic_handle_irq(irq); + break; + case DLN2_GPIO_EVENT_CHANGE_FALLING: + if (!event->value) + generic_handle_irq(irq); + break; + default: + generic_handle_irq(irq); + } +} + +static int dln2_gpio_probe(struct platform_device *pdev) +{ + struct dln2_gpio *dln2; + struct device *dev = &pdev->dev; + int pins; + int i, ret; + + pins = dln2_gpio_get_pin_count(pdev); + if (pins < 0) { + dev_err(dev, "failed to get pin count: %d\n", pins); + return pins; + } + if (pins > DLN2_GPIO_MAX_PINS) { + pins = DLN2_GPIO_MAX_PINS; + dev_warn(dev, "clamping pins to %d\n", DLN2_GPIO_MAX_PINS); + } + + dln2 = devm_kzalloc(&pdev->dev, sizeof(*dln2), GFP_KERNEL); + if (!dln2) + return -ENOMEM; + + dln2->irq_work = devm_kcalloc(&pdev->dev, pins, + sizeof(struct dln2_irq_work), GFP_KERNEL); + if (!dln2->irq_work) + return -ENOMEM; + for (i = 0; i < pins; i++) { + INIT_WORK(&dln2->irq_work[i].work, dln2_irq_work); + dln2->irq_work[i].pin = i; + dln2->irq_work[i].dln2 = dln2; + } + + dln2->pdev = pdev; + + dln2->gpio.label = "dln2"; + dln2->gpio.dev = dev; + dln2->gpio.owner = THIS_MODULE; + dln2->gpio.base = -1; + dln2->gpio.ngpio = pins; + dln2->gpio.exported = true; + dln2->gpio.can_sleep = true; + dln2->gpio.irq_not_threaded = true; + dln2->gpio.set = dln2_gpio_set; + dln2->gpio.get = dln2_gpio_get; + dln2->gpio.request = dln2_gpio_request; + dln2->gpio.free = dln2_gpio_free; + dln2->gpio.get_direction = dln2_gpio_get_direction; + dln2->gpio.direction_input = dln2_gpio_direction_input; + dln2->gpio.direction_output = dln2_gpio_direction_output; + dln2->gpio.set_debounce = dln2_gpio_set_debounce; + + platform_set_drvdata(pdev, dln2); + + ret = gpiochip_add(&dln2->gpio); + if (ret < 0) { + dev_err(dev, "failed to add gpio chip: %d\n", ret); + goto out; + } + + ret = gpiochip_irqchip_add(&dln2->gpio, &dln2_gpio_irqchip, 0, + handle_simple_irq, IRQ_TYPE_NONE); + if (ret < 0) { + dev_err(dev, "failed to add irq chip: %d\n", ret); + goto out_gpiochip_remove; + } + + ret = dln2_register_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV, + dln2_gpio_event); + if (ret) { + dev_err(dev, "failed to register event cb: %d\n", ret); + goto out_gpiochip_remove; + } + + return 0; + +out_gpiochip_remove: + gpiochip_remove(&dln2->gpio); +out: + return ret; +} + +static int dln2_gpio_remove(struct platform_device *pdev) +{ + struct dln2_gpio *dln2 = platform_get_drvdata(pdev); + int i; + + dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV); + for (i = 0; i < dln2->gpio.ngpio; i++) + flush_work(&dln2->irq_work[i].work); + gpiochip_remove(&dln2->gpio); + + return 0; +} + +static struct platform_driver dln2_gpio_driver = { + .driver.name = "dln2-gpio", + .probe = dln2_gpio_probe, + .remove = dln2_gpio_remove, +}; + +module_platform_driver(dln2_gpio_driver); + +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com"); +MODULE_DESCRIPTION("Driver for the Diolan DLN2 GPIO interface"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:dln2-gpio"); 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