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Commit 9c26df9b authored by William Breathitt Gray's avatar William Breathitt Gray Committed by Linus Walleij
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gpio: Add GPIO support for the WinSystems WS16C48 



The WinSystems WS16C48 device provides 48 lines of digital I/O. In
addition, the first 24 lines may be used for interrupt-handled edge
detection; rising edge detection and falling edge detection are
supported.

This driver provides GPIO and IRQ support for these 48 channels of
digital I/O. The base port address for the device may be configured via
the ws16c48_base module parameter. The interrupt line number for the
device may be configured via the ws16c48_irq module parameter.

Signed-off-by: default avatarWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 4332e014

MAINTAINERS

+6 −0
Original line number Diff line number Diff line
@@ -11871,6 +11871,12 @@ M: David Härdeman <david@hardeman.nu> 
S:	Maintained

F:	drivers/media/rc/winbond-cir.c



WINSYSTEMS WS16C48 GPIO DRIVER

M:	William Breathitt Gray <vilhelm.gray@gmail.com>

L:	linux-gpio@vger.kernel.org

S:	Maintained

F:	drivers/gpio/gpio-ws16c48.c



WIMAX STACK

M:	Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>

M:	linux-wimax@intel.com

drivers/gpio/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -570,6 +570,15 @@ config GPIO_TS5500 
	  blocks of the TS-5500: DIO1, DIO2 and the LCD port, and the TS-5600

	  LCD port.



config GPIO_WS16C48

	tristate "WinSystems WS16C48 GPIO support"

	select GPIOLIB_IRQCHIP

	help

	  Enables GPIO support for the WinSystems WS16C48. The base port address

	  for the device may be configured via the ws16c48_base module

	  parameter. The interrupt line number for the device may be configured

	  via the ws16c48_irq module parameter.



endmenu



menu "I2C GPIO expanders"

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ obj-$(CONFIG_GPIO_VX855) += gpio-vx855.o 
obj-$(CONFIG_GPIO_WM831X)	+= gpio-wm831x.o

obj-$(CONFIG_GPIO_WM8350)	+= gpio-wm8350.o

obj-$(CONFIG_GPIO_WM8994)	+= gpio-wm8994.o

obj-$(CONFIG_GPIO_WS16C48)	+= gpio-ws16c48.o

obj-$(CONFIG_GPIO_XGENE)	+= gpio-xgene.o

obj-$(CONFIG_GPIO_XGENE_SB)	+= gpio-xgene-sb.o

obj-$(CONFIG_GPIO_XILINX)	+= gpio-xilinx.o

drivers/gpio/gpio-ws16c48.c

0 → 100644
+436 −0
Original line number Diff line number Diff line 
/*

 * GPIO driver for the WinSystems WS16C48

 * Copyright (C) 2016 William Breathitt Gray

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License, version 2, as

 * published by the Free Software Foundation.

 *

 * 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.

 */

#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/errno.h>

#include <linux/gpio/driver.h>

#include <linux/io.h>

#include <linux/ioport.h>

#include <linux/interrupt.h>

#include <linux/irqdesc.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/platform_device.h>

#include <linux/spinlock.h>



static unsigned ws16c48_base;

module_param(ws16c48_base, uint, 0);

MODULE_PARM_DESC(ws16c48_base, "WinSystems WS16C48 base address");

static unsigned ws16c48_irq;

module_param(ws16c48_irq, uint, 0);

MODULE_PARM_DESC(ws16c48_irq, "WinSystems WS16C48 interrupt line number");



/**

 * struct ws16c48_gpio - GPIO device private data structure

 * @chip:	instance of the gpio_chip

 * @io_state:	bit I/O state (whether bit is set to input or output)

 * @out_state:	output bits state

 * @lock:	synchronization lock to prevent I/O race conditions

 * @irq_mask:	I/O bits affected by interrupts

 * @flow_mask:	IRQ flow type mask for the respective I/O bits

 * @base:	base port address of the GPIO device

 * @extent:	extent of port address region of the GPIO device

 * @irq:	Interrupt line number

 */

struct ws16c48_gpio {

	struct gpio_chip chip;

	unsigned char io_state[6];

	unsigned char out_state[6];

	spinlock_t lock;

	unsigned long irq_mask;

	unsigned long flow_mask;

	unsigned base;

	unsigned extent;

	unsigned irq;

};



static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)

{

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned port = offset / 8;

	const unsigned mask = BIT(offset % 8);



	return !!(ws16c48gpio->io_state[port] & mask);

}



static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)

{

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned port = offset / 8;

	const unsigned mask = BIT(offset % 8);

	unsigned long flags;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	ws16c48gpio->io_state[port] |= mask;

	ws16c48gpio->out_state[port] &= ~mask;

	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);



	return 0;

}



static int ws16c48_gpio_direction_output(struct gpio_chip *chip,

	unsigned offset, int value)

{

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned port = offset / 8;

	const unsigned mask = BIT(offset % 8);

	unsigned long flags;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	ws16c48gpio->io_state[port] &= ~mask;

	if (value)

		ws16c48gpio->out_state[port] |= mask;

	else

		ws16c48gpio->out_state[port] &= ~mask;

	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);



	return 0;

}



static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)

{

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned port = offset / 8;

	const unsigned mask = BIT(offset % 8);

	unsigned long flags;

	unsigned port_state;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	/* ensure that GPIO is set for input */

	if (!(ws16c48gpio->io_state[port] & mask)) {

		spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

		return -EINVAL;

	}



	port_state = inb(ws16c48gpio->base + port);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);



	return !!(port_state & mask);

}



static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)

{

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned port = offset / 8;

	const unsigned mask = BIT(offset % 8);

	unsigned long flags;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	/* ensure that GPIO is set for output */

	if (ws16c48gpio->io_state[port] & mask) {

		spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

		return;

	}



	if (value)

		ws16c48gpio->out_state[port] |= mask;

	else

		ws16c48gpio->out_state[port] &= ~mask;

	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

}



static void ws16c48_irq_ack(struct irq_data *data)

{

	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned long offset = irqd_to_hwirq(data);

	const unsigned port = offset / 8;

	const unsigned mask = BIT(offset % 8);

	unsigned long flags;

	unsigned port_state;



	/* only the first 3 ports support interrupts */

	if (port > 2)

		return;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	port_state = ws16c48gpio->irq_mask >> (8*port);



	outb(0x80, ws16c48gpio->base + 7);

	outb(port_state & ~mask, ws16c48gpio->base + 8 + port);

	outb(port_state | mask, ws16c48gpio->base + 8 + port);

	outb(0xC0, ws16c48gpio->base + 7);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

}



static void ws16c48_irq_mask(struct irq_data *data)

{

	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned long offset = irqd_to_hwirq(data);

	const unsigned long mask = BIT(offset);

	const unsigned port = offset / 8;

	unsigned long flags;



	/* only the first 3 ports support interrupts */

	if (port > 2)

		return;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	ws16c48gpio->irq_mask &= ~mask;



	outb(0x80, ws16c48gpio->base + 7);

	outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);

	outb(0xC0, ws16c48gpio->base + 7);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

}



static void ws16c48_irq_unmask(struct irq_data *data)

{

	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned long offset = irqd_to_hwirq(data);

	const unsigned long mask = BIT(offset);

	const unsigned port = offset / 8;

	unsigned long flags;



	/* only the first 3 ports support interrupts */

	if (port > 2)

		return;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	ws16c48gpio->irq_mask |= mask;



	outb(0x80, ws16c48gpio->base + 7);

	outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);

	outb(0xC0, ws16c48gpio->base + 7);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

}



static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)

{

	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);

	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);

	const unsigned long offset = irqd_to_hwirq(data);

	const unsigned long mask = BIT(offset);

	const unsigned port = offset / 8;

	unsigned long flags;



	/* only the first 3 ports support interrupts */

	if (port > 2)

		return -EINVAL;



	spin_lock_irqsave(&ws16c48gpio->lock, flags);



	switch (flow_type) {

	case IRQ_TYPE_NONE:

		break;

	case IRQ_TYPE_EDGE_RISING:

		ws16c48gpio->flow_mask |= mask;

		break;

	case IRQ_TYPE_EDGE_FALLING:

		ws16c48gpio->flow_mask &= ~mask;

		break;

	default:

		spin_unlock_irqrestore(&ws16c48gpio->lock, flags);

		return -EINVAL;

	}



	outb(0x40, ws16c48gpio->base + 7);

	outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);

	outb(0xC0, ws16c48gpio->base + 7);



	spin_unlock_irqrestore(&ws16c48gpio->lock, flags);



	return 0;

}



static struct irq_chip ws16c48_irqchip = {

	.name = "ws16c48",

	.irq_ack = ws16c48_irq_ack,

	.irq_mask = ws16c48_irq_mask,

	.irq_unmask = ws16c48_irq_unmask,

	.irq_set_type = ws16c48_irq_set_type

};



static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id)

{

	struct ws16c48_gpio *const ws16c48gpio = dev_id;

	struct gpio_chip *const chip = &ws16c48gpio->chip;

	unsigned long int_pending;

	unsigned long port;

	unsigned long int_id;

	unsigned long gpio;



	int_pending = inb(ws16c48gpio->base + 6) & 0x7;

	if (!int_pending)

		return IRQ_NONE;



	/* loop until all pending interrupts are handled */

	do {

		for_each_set_bit(port, &int_pending, 3) {

			int_id = inb(ws16c48gpio->base + 8 + port);

			for_each_set_bit(gpio, &int_id, 8)

				generic_handle_irq(irq_find_mapping(

					chip->irqdomain, gpio + 8*port));

		}



		int_pending = inb(ws16c48gpio->base + 6) & 0x7;

	} while (int_pending);



	return IRQ_HANDLED;

}



static int __init ws16c48_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct ws16c48_gpio *ws16c48gpio;

	const unsigned base = ws16c48_base;

	const unsigned extent = 16;

	const char *const name = dev_name(dev);

	int err;

	const unsigned irq = ws16c48_irq;



	ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL);

	if (!ws16c48gpio)

		return -ENOMEM;



	if (!request_region(base, extent, name)) {

		dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",

			name, base, base + extent);

		err = -EBUSY;

		goto err_lock_io_port;

	}



	ws16c48gpio->chip.label = name;

	ws16c48gpio->chip.parent = dev;

	ws16c48gpio->chip.owner = THIS_MODULE;

	ws16c48gpio->chip.base = -1;

	ws16c48gpio->chip.ngpio = 48;

	ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction;

	ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;

	ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;

	ws16c48gpio->chip.get = ws16c48_gpio_get;

	ws16c48gpio->chip.set = ws16c48_gpio_set;

	ws16c48gpio->base = base;

	ws16c48gpio->extent = extent;

	ws16c48gpio->irq = irq;



	spin_lock_init(&ws16c48gpio->lock);



	dev_set_drvdata(dev, ws16c48gpio);



	err = gpiochip_add_data(&ws16c48gpio->chip, ws16c48gpio);

	if (err) {

		dev_err(dev, "GPIO registering failed (%d)\n", err);

		goto err_gpio_register;

	}



	/* Disable IRQ by default */

	outb(0x80, base + 7);

	outb(0, base + 8);

	outb(0, base + 9);

	outb(0, base + 10);

	outb(0xC0, base + 7);



	err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_irqchip, 0,

		handle_edge_irq, IRQ_TYPE_NONE);

	if (err) {

		dev_err(dev, "Could not add irqchip (%d)\n", err);

		goto err_gpiochip_irqchip_add;

	}



	err = request_irq(irq, ws16c48_irq_handler, IRQF_SHARED, name,

		ws16c48gpio);

	if (err) {

		dev_err(dev, "IRQ handler registering failed (%d)\n", err);

		goto err_request_irq;

	}



	return 0;



err_request_irq:

err_gpiochip_irqchip_add:

	gpiochip_remove(&ws16c48gpio->chip);

err_gpio_register:

	release_region(base, extent);

err_lock_io_port:

	return err;

}



static int ws16c48_remove(struct platform_device *pdev)

{

	struct ws16c48_gpio *const ws16c48gpio = platform_get_drvdata(pdev);



	free_irq(ws16c48gpio->irq, ws16c48gpio);

	gpiochip_remove(&ws16c48gpio->chip);

	release_region(ws16c48gpio->base, ws16c48gpio->extent);



	return 0;

}



static struct platform_device *ws16c48_device;



static struct platform_driver ws16c48_driver = {

	.driver = {

		.name = "ws16c48"

	},

	.remove = ws16c48_remove

};



static void __exit ws16c48_exit(void)

{

	platform_device_unregister(ws16c48_device);

	platform_driver_unregister(&ws16c48_driver);

}



static int __init ws16c48_init(void)

{

	int err;



	ws16c48_device = platform_device_alloc(ws16c48_driver.driver.name, -1);

	if (!ws16c48_device)

		return -ENOMEM;



	err = platform_device_add(ws16c48_device);

	if (err)

		goto err_platform_device;



	err = platform_driver_probe(&ws16c48_driver, ws16c48_probe);

	if (err)

		goto err_platform_driver;



	return 0;



err_platform_driver:

	platform_device_del(ws16c48_device);

err_platform_device:

	platform_device_put(ws16c48_device);

	return err;

}



module_init(ws16c48_init);

module_exit(ws16c48_exit);



MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");

MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver");

MODULE_LICENSE("GPL");