gpio: sx150x: add Semtech I2C sx150x gpio expander driver

Add support for Semtech SX150-series I2C GPIO expanders.  Compatible
models include:

8 bits:  sx1508q
16 bits: sx1509q
Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Trilok Soni <tsoni@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpio/Kconfig

@@ -195,6 +195,17 @@ config GPIO_PCF857X
 	  This driver provides an in-kernel interface to those GPIOs using
 	  platform-neutral GPIO calls.
 
+config GPIO_SX150X
+	bool "Semtech SX150x I2C GPIO expander"
+	depends on I2C=y
+	default n
+	help
+	  Say yes here to provide support for Semtech SX150-series I2C
+	  GPIO expanders. Compatible models include:
+
+	  8 bits:  sx1508q
+	  16 bits: sx1509q
+
 config GPIO_TC35892
 	bool "TC35892 GPIOs"
 	depends on MFD_TC35892

drivers/gpio/Makefile

@@ -35,3 +35,4 @@ obj-$(CONFIG_GPIO_WM8994)	+= wm8994-gpio.o
 obj-$(CONFIG_GPIO_SCH)		+= sch_gpio.o
 obj-$(CONFIG_GPIO_RDC321X)	+= rdc321x-gpio.o
 obj-$(CONFIG_GPIO_JANZ_TTL)	+= janz-ttl.o
+obj-$(CONFIG_GPIO_SX150X)	+= sx150x.o

include/linux/i2c/sx150x.h

+/*
+ * Driver for the Semtech SX150x I2C GPIO Expanders
+ *
+ * Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#ifndef __LINUX_I2C_SX150X_H
+#define __LINUX_I2C_SX150X_H
+
+/**
+ * struct sx150x_platform_data - config data for SX150x driver
+ * @gpio_base: The index number of the first GPIO assigned to this
+ *             GPIO expander.  The expander will create a block of
+ *             consecutively numbered gpios beginning at the given base,
+ *             with the size of the block depending on the model of the
+ *             expander chip.
+ * @oscio_is_gpo: If set to true, the driver will configure OSCIO as a GPO
+ *                instead of as an oscillator, increasing the size of the
+ *                GP(I)O pool created by this expander by one.  The
+ *                output-only GPO pin will be added at the end of the block.
+ * @io_pullup_ena: A bit-mask which enables or disables the pull-up resistor
+ *                 for each IO line in the expander.  Setting the bit at
+ *                 position n will enable the pull-up for the IO at
+ *                 the corresponding offset.  For chips with fewer than
+ *                 16 IO pins, high-end bits are ignored.
+ * @io_pulldn_ena: A bit-mask which enables-or disables the pull-down
+ *                 resistor for each IO line in the expander. Setting the
+ *                 bit at position n will enable the pull-down for the IO at
+ *                 the corresponding offset.  For chips with fewer than
+ *                 16 IO pins, high-end bits are ignored.
+ * @io_open_drain_ena: A bit-mask which enables-or disables open-drain
+ *                     operation for each IO line in the expander. Setting the
+ *                     bit at position n enables open-drain operation for
+ *                     the IO at the corresponding offset.  Clearing the bit
+ *                     enables regular push-pull operation for that IO.
+ *                     For chips with fewer than 16 IO pins, high-end bits
+ *                     are ignored.
+ * @io_polarity: A bit-mask which enables polarity inversion for each IO line
+ *               in the expander.  Setting the bit at position n inverts
+ *               the polarity of that IO line, while clearing it results
+ *               in normal polarity. For chips with fewer than 16 IO pins,
+ *               high-end bits are ignored.
+ * @irq_summary: The 'summary IRQ' line to which the GPIO expander's INT line
+ *               is connected, via which it reports interrupt events
+ *               across all GPIO lines.  This must be a real,
+ *               pre-existing IRQ line.
+ *               Setting this value < 0 disables the irq_chip functionality
+ *               of the driver.
+ * @irq_base: The first 'virtual IRQ' line at which our block of GPIO-based
+ *            IRQ lines will appear.  Similarly to gpio_base, the expander
+ *            will create a block of irqs beginning at this number.
+ *            This value is ignored if irq_summary is < 0.
+ */
+struct sx150x_platform_data {
+	unsigned gpio_base;
+	bool     oscio_is_gpo;
+	u16      io_pullup_ena;
+	u16      io_pulldn_ena;
+	u16      io_open_drain_ena;
+	u16      io_polarity;
+	int      irq_summary;
+	unsigned irq_base;
+};
+
+#endif /* __LINUX_I2C_SX150X_H */