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Message-Id: <1268930324-29841-4-git-send-email-iws@ovro.caltech.edu>
Date: Thu, 18 Mar 2010 09:38:44 -0700
From: "Ira W. Snyder" <iws@...o.caltech.edu>
To: linux-kernel@...r.kernel.org
Cc: netdev@...r.kernel.org, sameo@...ux.intel.com,
socketcan-core@...ts.berlios.de
Subject: [PATCH 3/3] gpio: add support for Janz VMOD-TTL Digital IO module
The Janz VMOD-TTL is a MODULbus daughterboard which fits onto any MODULbus
carrier board. It essentially consists of some various logic and a Zilog
Z8536 CIO Counter/Timer and Parallel IO Unit.
The board must be physically configured with jumpers to enable a user to
drive output signals. I am only interested in outputs, so I have made this
driver as simple as possible. It only supports a very minimal amount of the
features provided by the Z8536 chip.
Signed-off-by: Ira W. Snyder <iws@...o.caltech.edu>
---
drivers/gpio/Kconfig | 10 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/janz-ttl.c | 257 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 268 insertions(+), 0 deletions(-)
create mode 100644 drivers/gpio/janz-ttl.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 1f1d88a..0da364d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -255,4 +255,14 @@ config GPIO_UCB1400
To compile this driver as a module, choose M here: the
module will be called ucb1400_gpio.
+comment "MODULbus GPIO expanders:"
+
+config GPIO_JANZ_TTL
+ tristate "Janz VMOD-TTL Digital IO Module"
+ depends on MFD_JANZ_CMODIO
+ help
+ This enables support for the Janz VMOD-TTL Digital IO module.
+ This driver provides support for driving the pins in output
+ mode only. Input mode is not supported.
+
endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 4868723..2263966 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_GPIO_CS5535) += cs5535-gpio.o
obj-$(CONFIG_GPIO_BT8XX) += bt8xxgpio.o
obj-$(CONFIG_GPIO_VR41XX) += vr41xx_giu.o
obj-$(CONFIG_GPIO_WM831X) += wm831x-gpio.o
+obj-$(CONFIG_GPIO_JANZ_TTL) += janz-ttl.o
diff --git a/drivers/gpio/janz-ttl.c b/drivers/gpio/janz-ttl.c
new file mode 100644
index 0000000..d97eeda
--- /dev/null
+++ b/drivers/gpio/janz-ttl.c
@@ -0,0 +1,257 @@
+/*
+ * Janz MODULbus VMOD-TTL GPIO Driver
+ *
+ * Copyright (c) 2010 Ira W. Snyder <iws@...o.caltech.edu>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+
+#include <linux/mfd/janz.h>
+
+#define DRV_NAME "janz-ttl"
+
+#define PORTA_DIRECTION 0x23
+#define PORTB_DIRECTION 0x2B
+#define PORTC_DIRECTION 0x06
+#define PORTA_IOCTL 0x24
+#define PORTB_IOCTL 0x2C
+#define PORTC_IOCTL 0x07
+
+#define MASTER_INT_CTL 0x00
+#define MASTER_CONF_CTL 0x01
+
+#define CONF_PAE (1 << 2)
+#define CONF_PBE (1 << 7)
+#define CONF_PCE (1 << 4)
+
+struct ttl_control_regs {
+ __be16 portc;
+ __be16 portb;
+ __be16 porta;
+ __be16 control;
+};
+
+struct ttl_module {
+ struct gpio_chip gpio;
+
+ /* base address of registers */
+ struct ttl_control_regs __iomem *regs;
+
+ u8 portc_shadow;
+ u8 portb_shadow;
+ u8 porta_shadow;
+
+ spinlock_t lock;
+};
+
+static int ttl_get_value(struct gpio_chip *gpio, unsigned offset)
+{
+ struct ttl_module *mod = dev_get_drvdata(gpio->dev);
+ u8 *shadow;
+ int ret;
+
+ if (offset < 8) {
+ shadow = &mod->porta_shadow;
+ } else if (offset < 16) {
+ shadow = &mod->portb_shadow;
+ offset -= 8;
+ } else {
+ shadow = &mod->portc_shadow;
+ offset -= 16;
+ }
+
+ spin_lock(&mod->lock);
+ ret = *shadow & (1 << offset);
+ spin_unlock(&mod->lock);
+ return ret;
+}
+
+static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value)
+{
+ struct ttl_module *mod = dev_get_drvdata(gpio->dev);
+ void __iomem *port;
+ u8 *shadow;
+
+ if (offset < 8) {
+ port = &mod->regs->porta;
+ shadow = &mod->porta_shadow;
+ } else if (offset < 16) {
+ port = &mod->regs->portb;
+ shadow = &mod->portb_shadow;
+ offset -= 8;
+ } else {
+ port = &mod->regs->portc;
+ shadow = &mod->portc_shadow;
+ offset -= 16;
+ }
+
+ spin_lock(&mod->lock);
+ if (value)
+ *shadow |= (1 << offset);
+ else
+ *shadow &= ~(1 << offset);
+
+ iowrite16be(*shadow, port);
+ spin_unlock(&mod->lock);
+}
+
+static void __devinit ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val)
+{
+ iowrite16be(reg, &mod->regs->control);
+ iowrite16be(val, &mod->regs->control);
+}
+
+static void __devinit ttl_setup_device(struct ttl_module *mod)
+{
+ /* reset the device to a known state */
+ iowrite16be(0x0000, &mod->regs->control);
+ iowrite16be(0x0001, &mod->regs->control);
+ iowrite16be(0x0000, &mod->regs->control);
+
+ /* put all ports in open-drain mode */
+ ttl_write_reg(mod, PORTA_IOCTL, 0x00ff);
+ ttl_write_reg(mod, PORTB_IOCTL, 0x00ff);
+ ttl_write_reg(mod, PORTC_IOCTL, 0x000f);
+
+ /* set all ports as outputs */
+ ttl_write_reg(mod, PORTA_DIRECTION, 0x0000);
+ ttl_write_reg(mod, PORTB_DIRECTION, 0x0000);
+ ttl_write_reg(mod, PORTC_DIRECTION, 0x0000);
+
+ /* set all ports to drive zeroes */
+ iowrite16be(0x0000, &mod->regs->porta);
+ iowrite16be(0x0000, &mod->regs->portb);
+ iowrite16be(0x0000, &mod->regs->portc);
+
+ /* enable all ports */
+ ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE);
+}
+
+static int __devinit ttl_probe(struct platform_device *pdev)
+{
+ struct janz_platform_data *pdata;
+ struct device *dev = &pdev->dev;
+ struct ttl_module *mod;
+ struct gpio_chip *gpio;
+ struct resource *res;
+ int ret;
+
+ pdata = pdev->dev.platform_data;
+ if (!pdata) {
+ dev_err(dev, "no platform data\n");
+ ret = -ENXIO;
+ goto out_return;
+ }
+
+ mod = kzalloc(sizeof(*mod), GFP_KERNEL);
+ if (!mod) {
+ dev_err(dev, "unable to allocate private data\n");
+ ret = -ENOMEM;
+ goto out_return;
+ }
+
+ platform_set_drvdata(pdev, mod);
+ spin_lock_init(&mod->lock);
+
+ /* get access to the MODULbus registers for this module */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "MODULbus registers not found\n");
+ ret = -ENODEV;
+ goto out_free_mod;
+ }
+
+ mod->regs = ioremap(res->start, resource_size(res));
+ if (!mod->regs) {
+ dev_err(dev, "MODULbus registers not ioremap\n");
+ ret = -ENOMEM;
+ goto out_free_mod;
+ }
+
+ ttl_setup_device(mod);
+
+ /* Initialize the GPIO data structures */
+ gpio = &mod->gpio;
+ gpio->dev = &pdev->dev;
+ gpio->label = pdev->name;
+ gpio->get = ttl_get_value;
+ gpio->set = ttl_set_value;
+ gpio->owner = THIS_MODULE;
+
+ /* request dynamic allocation */
+ gpio->base = -1;
+ gpio->ngpio = 20;
+
+ ret = gpiochip_add(gpio);
+ if (ret) {
+ dev_err(dev, "unable to add GPIO chip\n");
+ goto out_iounmap_regs;
+ }
+
+ dev_info(&pdev->dev, "module %d: registered GPIO device\n",
+ pdata->modno);
+ return 0;
+
+out_iounmap_regs:
+ iounmap(mod->regs);
+out_free_mod:
+ kfree(mod);
+out_return:
+ return ret;
+}
+
+static int __devexit ttl_remove(struct platform_device *pdev)
+{
+ struct ttl_module *mod = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ ret = gpiochip_remove(&mod->gpio);
+ if (ret) {
+ dev_err(dev, "unable to remove GPIO chip\n");
+ return ret;
+ }
+
+ iounmap(mod->regs);
+ kfree(mod);
+ return 0;
+}
+
+static struct platform_driver ttl_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+ .probe = ttl_probe,
+ .remove = __devexit_p(ttl_remove),
+};
+
+static int __init ttl_init(void)
+{
+ return platform_driver_register(&ttl_driver);
+}
+
+static void __exit ttl_exit(void)
+{
+ platform_driver_unregister(&ttl_driver);
+}
+
+MODULE_AUTHOR("Ira W. Snyder <iws@...o.caltech.edu>");
+MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:janz-ttl");
+
+module_init(ttl_init);
+module_exit(ttl_exit);
--
1.5.4.3
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