Commit 6732127f authored by Daniel Baluta's avatar Daniel Baluta Committed by Lee Jones
Browse files

gpio: add support for the Diolan DLN-2 USB GPIO driver 

This patch adds GPIO and IRQ support for the Diolan DLN-2 GPIO module.

Information about the USB protocol interface can be found in the
Programmer's Reference Manual [1], see section 2.9 for the GPIO
module commands and responses.

[1] https://www.diolan.com/downloads/dln-api-manual.pdf



Signed-off-by: default avatarDaniel Baluta <daniel.baluta@intel.com>
Signed-off-by: default avatarOctavian Purdila <octavian.purdila@intel.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent db23e500

drivers/gpio/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -905,4 +905,16 @@ config GPIO_VIPERBOARD 
          River Tech's viperboard.h for detailed meaning

          of the module parameters.



config GPIO_DLN2

	tristate "Diolan DLN2 GPIO support"

	depends on MFD_DLN2

	select GPIOLIB_IRQCHIP



	help

	  Select this option to enable GPIO driver for the Diolan DLN2

	  board.



	  This driver can also be built as a module. If so, the module

	  will be called gpio-dln2.



endif

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ obj-$(CONFIG_GPIO_CRYSTAL_COVE) += gpio-crystalcove.o 
obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o

obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o

obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o

obj-$(CONFIG_GPIO_DLN2)		+= gpio-dln2.o

obj-$(CONFIG_GPIO_DWAPB)	+= gpio-dwapb.o

obj-$(CONFIG_GPIO_EM)		+= gpio-em.o

obj-$(CONFIG_GPIO_EP93XX)	+= gpio-ep93xx.o

drivers/gpio/gpio-dln2.c

0 → 100644
+553 −0
Original line number Diff line number Diff line 
/*

 * 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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