path: root/target/linux/ixp4xx/patches-2.6.35/020-gateworks_i2c_pld.patch

--- /dev/null
+++ b/drivers/gpio/gw_i2c_pld.c
@@ -0,0 +1,371 @@
+/*
+ * Gateworks I2C PLD GPIO expander
+ *
+ * Copyright (C) 2009 Gateworks 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; 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/slab.h>
+#include <linux/hardirq.h>
+#include <linux/i2c.h>
+#include <linux/i2c/gw_i2c_pld.h>
+#include <asm/gpio.h>
+
+static const struct i2c_device_id gw_i2c_pld_id[] = {
+	{ "gw_i2c_pld", 8 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, gw_i2c_pld_id);
+
+/*
+ * The Gateworks I2C PLD chip only expose one read and one
+ * write register.  Writing a "one" bit (to match the reset state) lets
+ * that pin be used as an input. It is an open-drain model.
+ */
+
+struct gw_i2c_pld {
+	struct gpio_chip	chip;
+	struct i2c_client	*client;
+	unsigned		out;		/* software latch */
+};
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * The Gateworks I2C PLD chip does not properly send the acknowledge bit
+ * thus we cannot use standard i2c_smbus functions. We have recreated
+ * our own here, but we still use the mutex_lock to lock the i2c_bus
+ * as the device still exists on the I2C bus.
+*/
+
+#define PLD_SCL_GPIO 6
+#define PLD_SDA_GPIO 7
+
+#define SCL_LO()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_LOW)
+#define SCL_HI()  gpio_line_set(PLD_SCL_GPIO, IXP4XX_GPIO_HIGH)
+#define SCL_EN()  gpio_line_config(PLD_SCL_GPIO, IXP4XX_GPIO_OUT)
+#define SDA_LO()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_LOW)
+#define SDA_HI()  gpio_line_set(PLD_SDA_GPIO, IXP4XX_GPIO_HIGH)
+#define SDA_EN()  gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_OUT)
+#define SDA_DIS() gpio_line_config(PLD_SDA_GPIO, IXP4XX_GPIO_IN)
+#define SDA_IN(x) gpio_line_get(PLD_SDA_GPIO, &x);
+
+static int i2c_pld_write_byte(int address, int byte)
+{
+	int i;
+
+	address = (address << 1) & ~0x1;
+
+	SDA_HI();
+	SDA_EN();
+	SCL_EN();
+	SCL_HI();
+	SDA_LO();
+	SCL_LO();
+
+	for (i = 7; i >= 0; i--)
+	{
+		if (address & (1 << i))
+			SDA_HI();
+		else
+			SDA_LO();
+
+		SCL_HI();
+		SCL_LO();
+	}
+
+	SDA_DIS();
+	SCL_HI();
+	SDA_IN(i);
+	SCL_LO();
+	SDA_EN();
+
+	for (i = 7; i >= 0; i--)
+	{
+		if (byte & (1 << i))
+      SDA_HI();
+		else
+			SDA_LO();
+		SCL_HI();
+		SCL_LO();
+	}
+
+	SDA_DIS();
+	SCL_HI();
+	SDA_IN(i);
+	SCL_LO();
+
+	SDA_HI();
+	SDA_EN();
+
+	SDA_LO();
+	SCL_HI();
+	SDA_HI();
+	SCL_LO();
+	SCL_HI();
+
+	return 0;
+}
+
+static unsigned int i2c_pld_read_byte(int address)
+{
+	int i = 0, byte = 0;
+	int bit;
+
+	address = (address << 1) | 0x1;
+
+	SDA_HI();
+	SDA_EN();
+	SCL_EN();
+	SCL_HI();
+	SDA_LO();
+	SCL_LO();
+
+	for (i = 7; i >= 0; i--)
+	{
+		if (address & (1 << i))
+			SDA_HI();
+		else
+			SDA_LO();
+
+		SCL_HI();
+		SCL_LO();
+	}
+
+	SDA_DIS();
+	SCL_HI();
+	SDA_IN(i);
+	SCL_LO();
+	SDA_EN();
+
+	SDA_DIS();
+	for (i = 7; i >= 0; i--)
+	{
+		SCL_HI();
+		SDA_IN(bit);
+		byte |= bit << i;
+		SCL_LO();
+	}
+
+	SDA_LO();
+	SCL_HI();
+	SDA_HI();
+	SCL_LO();
+	SCL_HI();
+
+	return byte;
+}
+
+
+static int gw_i2c_pld_input8(struct gpio_chip *chip, unsigned offset)
+{
+	int ret;
+	struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
+	struct i2c_adapter *adap = gpio->client->adapter;
+	
+	if (in_atomic() || irqs_disabled()) {
+		ret = mutex_trylock(&adap->bus_lock);
+		if (!ret)
+			/* I2C activity is ongoing. */
+			return -EAGAIN;
+	} else {
+		mutex_lock_nested(&adap->bus_lock, adap->level);
+	}
+
+	gpio->out |= (1 << offset);
+
+	ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
+
+	mutex_unlock(&adap->bus_lock);
+
+	return ret;
+}
+
+static int gw_i2c_pld_get8(struct gpio_chip *chip, unsigned offset)
+{
+	int ret;
+	s32	value;
+	struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
+	struct i2c_adapter *adap = gpio->client->adapter;
+	
+	if (in_atomic() || irqs_disabled()) {
+		ret = mutex_trylock(&adap->bus_lock);
+		if (!ret)
+			/* I2C activity is ongoing. */
+			return -EAGAIN;
+	} else {
+		mutex_lock_nested(&adap->bus_lock, adap->level);
+	}
+
+	value = i2c_pld_read_byte(gpio->client->addr);
+
+	mutex_unlock(&adap->bus_lock);
+
+	return (value < 0) ? 0 : (value & (1 << offset));
+}
+
+static int gw_i2c_pld_output8(struct gpio_chip *chip, unsigned offset, int value)
+{
+	int ret;
+
+	struct gw_i2c_pld *gpio = container_of(chip, struct gw_i2c_pld, chip);
+	struct i2c_adapter *adap = gpio->client->adapter;
+
+	unsigned bit = 1 << offset;
+	
+	if (in_atomic() || irqs_disabled()) {
+		ret = mutex_trylock(&adap->bus_lock);
+		if (!ret)
+			/* I2C activity is ongoing. */
+			return -EAGAIN;
+	} else {
+		mutex_lock_nested(&adap->bus_lock, adap->level);
+	}
+
+
+	if (value)
+		gpio->out |= bit;
+	else
+		gpio->out &= ~bit;
+
+	ret = i2c_pld_write_byte(gpio->client->addr, gpio->out);
+
+	mutex_unlock(&adap->bus_lock);
+
+	return ret;
+}
+
+static void gw_i2c_pld_set8(struct gpio_chip *chip, unsigned offset, int value)
+{
+	gw_i2c_pld_output8(chip, offset, value);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int gw_i2c_pld_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct gw_i2c_pld_platform_data	*pdata;
+	struct gw_i2c_pld *gpio;
+	int status;
+
+	pdata = client->dev.platform_data;
+	if (!pdata)
+		return -ENODEV;
+
+	/* Allocate, initialize, and register this gpio_chip. */
+	gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	gpio->chip.base = pdata->gpio_base;
+	gpio->chip.can_sleep = 1;
+	gpio->chip.dev = &client->dev;
+	gpio->chip.owner = THIS_MODULE;
+
+	gpio->chip.ngpio = pdata->nr_gpio;
+	gpio->chip.direction_input = gw_i2c_pld_input8;
+	gpio->chip.get = gw_i2c_pld_get8;
+	gpio->chip.direction_output = gw_i2c_pld_output8;
+	gpio->chip.set = gw_i2c_pld_set8;
+
+	gpio->chip.label = client->name;
+
+	gpio->client = client;
+	i2c_set_clientdata(client, gpio);
+
+	gpio->out = 0xFF;
+
+	status = gpiochip_add(&gpio->chip);
+	if (status < 0)
+		goto fail;
+
+	dev_info(&client->dev, "gpios %d..%d on a %s%s\n",
+			gpio->chip.base,
+			gpio->chip.base + gpio->chip.ngpio - 1,
+			client->name,
+			client->irq ? " (irq ignored)" : "");
+
+	/* Let platform code set up the GPIOs and their users.
+	 * Now is the first time anyone could use them.
+	 */
+	if (pdata->setup) {
+		status = pdata->setup(client,
+				gpio->chip.base, gpio->chip.ngpio,
+				pdata->context);
+		if (status < 0)
+			dev_warn(&client->dev, "setup --> %d\n", status);
+	}
+
+	return 0;
+
+fail:
+	dev_dbg(&client->dev, "probe error %d for '%s'\n",
+			status, client->name);
+	kfree(gpio);
+	return status;
+}
+
+static int gw_i2c_pld_remove(struct i2c_client *client)
+{
+	struct gw_i2c_pld_platform_data	*pdata = client->dev.platform_data;
+	struct gw_i2c_pld *gpio = i2c_get_clientdata(client);
+	int				status = 0;
+
+	if (pdata->teardown) {
+		status = pdata->teardown(client,
+				gpio->chip.base, gpio->chip.ngpio,
+				pdata->context);
+		if (status < 0) {
+			dev_err(&client->dev, "%s --> %d\n",
+					"teardown", status);
+			return status;
+		}
+	}
+
+	status = gpiochip_remove(&gpio->chip);
+	if (status == 0)
+		kfree(gpio);
+	else
+		dev_err(&client->dev, "%s --> %d\n", "remove", status);
+	return status;
+}
+
+static struct i2c_driver gw_i2c_pld_driver = {
+	.driver = {
+		.name	= "gw_i2c_pld",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= gw_i2c_pld_probe,
+	.remove	= gw_i2c_pld_remove,
+	.id_table = gw_i2c_pld_id,
+};
+
+static int __init gw_i2c_pld_init(void)
+{
+	return i2c_add_driver(&gw_i2c_pld_driver);
+}
+module_init(gw_i2c_pld_init);
+
+static void __exit gw_i2c_pld_exit(void)
+{
+	i2c_del_driver(&gw_i2c_pld_driver);
+}
+module_exit(gw_i2c_pld_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Chris Lang");
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -221,6 +221,14 @@ config GPIO_TIMBERDALE
 	---help---
 	Add support for the GPIO IP in the timberdale FPGA.
 
+config GPIO_GW_I2C_PLD
+	tristate "Gateworks I2C PLD GPIO Expander"
+	depends on I2C
+	help
+		Say yes here to provide access to the Gateworks I2C PLD GPIO
+		Expander. This is used at least on the GW2358-4.
+
+
 comment "SPI GPIO expanders:"
 
 config GPIO_MAX7301
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -31,3 +31,4 @@ obj-$(CONFIG_GPIO_WM8994)	+= wm8994-gpio
 obj-$(CONFIG_GPIO_SCH)		+= sch_gpio.o
 obj-$(CONFIG_GPIO_RDC321X)	+= rdc321x-gpio.o
 obj-$(CONFIG_GPIO_JANZ_TTL)	+= janz-ttl.o
+obj-$(CONFIG_GPIO_GW_I2C_PLD)	+= gw_i2c_pld.o
--- /dev/null
+++ b/include/linux/i2c/gw_i2c_pld.h
@@ -0,0 +1,20 @@
+#ifndef __LINUX_GW_I2C_PLD_H
+#define __LINUX_GW_I2C_PLD_H
+
+/**
+ * The Gateworks I2C PLD Implements an additional 8 bits of GPIO through the PLD
+ */
+
+struct gw_i2c_pld_platform_data {
+	unsigned gpio_base;
+	unsigned nr_gpio;
+	int		(*setup)(struct i2c_client *client,
+					int gpio, unsigned ngpio,
+					void *context);
+	int		(*teardown)(struct i2c_client *client,
+					int gpio, unsigned ngpio,
+					void *context);
+	void		*context;
+};
+
+#endif /* __LINUX_GW_I2C_PLD_H */