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Message-ID: <4A3663A8.1030508@mocean-labs.com>
Date: Mon, 15 Jun 2009 17:07:20 +0200
From: Richard Röjfors
<richard.rojfors.ext@...ean-labs.com>
To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH v2] gpio: Added MC33880 driver
Supplied is a GPIO driver for the Freescale MC33880 High/Low side
switch
Signed-off-by: Richard Röjfors <richard.rojfors.ext@...ean-labs.com>
---
Index: linux-2.6.30-rc7/drivers/gpio/mc33880.c
===================================================================
--- linux-2.6.30-rc7/drivers/gpio/mc33880.c (revision 0)
+++ linux-2.6.30-rc7/drivers/gpio/mc33880.c (revision 864)
@@ -0,0 +1,196 @@
+/*
+ * mc33880.c MC33880 high-side/low-side switch GPIO driver
+ * Copyright (c) 2009 Intel Corporation
+ *
+ * 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.
+ *
+ * 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.
+ */
+
+/* Supports:
+ * Freescale MC33880 high-side/low-side switch
+ */
+
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/mc33880.h>
+#include <linux/gpio.h>
+
+#define DRIVER_NAME "mc33880"
+
+/*
+ * Pin configurations, see MAX7301 datasheet page 6
+ */
+#define PIN_CONFIG_MASK 0x03
+#define PIN_CONFIG_IN_PULLUP 0x03
+#define PIN_CONFIG_IN_WO_PULLUP 0x02
+#define PIN_CONFIG_OUT 0x01
+
+#define PIN_NUMBER 8
+
+
+/*
+ * Some registers must be read back to modify.
+ * To save time we cache them here in memory
+ */
+struct mc33880 {
+ struct mutex lock; /* protect from simultanous accesses */
+ u8 port_config;
+ struct gpio_chip chip;
+ struct spi_device *spi;
+};
+
+static int mc33880_write_config(struct mc33880 *mc)
+{
+ return spi_write(mc->spi, &mc->port_config, sizeof(mc->port_config));
+}
+
+
+static int __mc33880_set(struct mc33880 *mc, unsigned offset, int value)
+{
+ if (value)
+ mc->port_config |= 1 << offset;
+ else
+ mc->port_config &= ~(1 << offset);
+
+ return mc33880_write_config(mc);
+}
+
+
+static void mc33880_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ struct mc33880 *mc = container_of(chip, struct mc33880, chip);
+
+ mutex_lock(&mc->lock);
+
+ __mc33880_set(mc, offset, value);
+
+ mutex_unlock(&mc->lock);
+}
+
+static int __devinit mc33880_probe(struct spi_device *spi)
+{
+ struct mc33880 *mc;
+ struct mc33880_platform_data *pdata;
+ int ret;
+
+ pdata = spi->dev.platform_data;
+ if (!pdata || !pdata->base) {
+ dev_dbg(&spi->dev, "incorrect or missing platform data\n");
+ return -EINVAL;
+ }
+
+ /*
+ * bits_per_word cannot be configured in platform data
+ */
+ spi->bits_per_word = 8;
+
+ ret = spi_setup(spi);
+ if (ret < 0)
+ return ret;
+
+ mc = kzalloc(sizeof(struct mc33880), GFP_KERNEL);
+ if (!mc)
+ return -ENOMEM;
+
+ mutex_init(&mc->lock);
+
+ dev_set_drvdata(&spi->dev, mc);
+
+ mc->spi = spi;
+
+ mc->chip.label = DRIVER_NAME,
+ mc->chip.set = mc33880_set;
+ mc->chip.base = pdata->base;
+ mc->chip.ngpio = PIN_NUMBER;
+ mc->chip.can_sleep = 1;
+ mc->chip.dev = &spi->dev;
+ mc->chip.owner = THIS_MODULE;
+
+ mc->port_config = 0x00;
+ /* write twice, because during initialisation the first setting
+ * is just for testing SPI communication, and the second is the
+ * "real" configuration
+ */
+ ret = mc33880_write_config(mc);
+ mc->port_config = 0x00;
+ if (!ret)
+ ret = mc33880_write_config(mc);
+
+ if (ret) {
+ printk(KERN_ERR "Failed writing to " DRIVER_NAME ": %d\n", ret);
+ goto exit_destroy;
+ }
+
+ ret = gpiochip_add(&mc->chip);
+ if (ret)
+ goto exit_destroy;
+
+ return ret;
+
+exit_destroy:
+ dev_set_drvdata(&spi->dev, NULL);
+ mutex_destroy(&mc->lock);
+ kfree(mc);
+ return ret;
+}
+
+static int mc33880_remove(struct spi_device *spi)
+{
+ struct mc33880 *mc;
+ int ret;
+
+ mc = dev_get_drvdata(&spi->dev);
+ if (mc == NULL)
+ return -ENODEV;
+
+ dev_set_drvdata(&spi->dev, NULL);
+
+ ret = gpiochip_remove(&mc->chip);
+ if (!ret) {
+ mutex_destroy(&mc->lock);
+ kfree(mc);
+ } else
+ dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
+ ret);
+
+ return ret;
+}
+
+static struct spi_driver mc33880_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+ .probe = mc33880_probe,
+ .remove = __devexit_p(mc33880_remove),
+};
+
+static int __init mc33880_init(void)
+{
+ return spi_register_driver(&mc33880_driver);
+}
+/* register after spi postcore initcall and before
+ * subsys initcalls that may rely on these GPIOs
+ */
+subsys_initcall(mc33880_init);
+
+static void __exit mc33880_exit(void)
+{
+ spi_unregister_driver(&mc33880_driver);
+}
+module_exit(mc33880_exit);
+
+MODULE_AUTHOR("Mocean Laboratories <info@...ean-labs.com>");
+MODULE_LICENSE("GPL v2");
+
Index: linux-2.6.30-rc7/drivers/gpio/Kconfig
===================================================================
--- linux-2.6.30-rc7/drivers/gpio/Kconfig (revision 861)
+++ linux-2.6.30-rc7/drivers/gpio/Kconfig (working copy)
@@ -176,4 +176,11 @@
SPI driver for Microchip MCP23S08 I/O expander. This provides
a GPIO interface supporting inputs and outputs.
+config GPIO_MC33880
+ tristate "Freescale MC33880 high-side/low-side switch"
+ depends on SPI_MASTER
+ help
+ SPI driver for Freescale MC33880 high-side/low-side switch.
+ This provides GPIO interface supporting inputs and outputs.
+
endif
Index: linux-2.6.30-rc7/drivers/gpio/Makefile
===================================================================
--- linux-2.6.30-rc7/drivers/gpio/Makefile (revision 861)
+++ linux-2.6.30-rc7/drivers/gpio/Makefile (working copy)
@@ -12,3 +12,5 @@
obj-$(CONFIG_GPIO_TWL4030) += twl4030-gpio.o
obj-$(CONFIG_GPIO_XILINX) += xilinx_gpio.o
obj-$(CONFIG_GPIO_BT8XX) += bt8xxgpio.o
+obj-$(CONFIG_GPIO_MC33880) += mc33880.o
+
Index: linux-2.6.30-rc7/include/linux/spi/mc33880.h
===================================================================
--- linux-2.6.30-rc7/include/linux/spi/mc33880.h (revision 0)
+++ linux-2.6.30-rc7/include/linux/spi/mc33880.h (revision 864)
@@ -0,0 +1,10 @@
+#ifndef LINUX_SPI_MC33880_H
+#define LINUX_SPI_MC33880_H
+
+struct mc33880_platform_data {
+ /* number assigned to the first GPIO */
+ unsigned base;
+};
+
+#endif
+
--
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