[ARM] 4947/1: htc-egpio, a driver for GPIO/IRQ expanders with fixed input/output pins

implemented in CPLD chips on several HTC devices.

The original driver was written by Kevin O'Connor, I have adapted it to
use gpiolib and made the bus/register widths configurable.
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mfd/Kconfig

@@ -22,6 +22,14 @@ config MFD_ASIC3
 	  This driver supports the ASIC3 multifunction chip found on many
 	  PDAs (mainly iPAQ and HTC based ones)
 
+config HTC_EGPIO
+	bool "HTC EGPIO support"
+	depends on GENERIC_HARDIRQS && HAVE_GPIO_LIB
+	help
+	    This driver supports the CPLD egpio chip present on
+	    several HTC phones.  It provides basic support for input
+	    pins, output pins, and irqs.
+
 endmenu
 
 menu "Multimedia Capabilities Port drivers"

drivers/mfd/Makefile

@@ -5,6 +5,8 @@
 obj-$(CONFIG_MFD_SM501)		+= sm501.o
 obj-$(CONFIG_MFD_ASIC3)		+= asic3.o
 
+obj-$(CONFIG_HTC_EGPIO)		+= htc-egpio.o
+
 obj-$(CONFIG_MCP)		+= mcp-core.o
 obj-$(CONFIG_MCP_SA11X0)	+= mcp-sa11x0.o
 obj-$(CONFIG_MCP_UCB1200)	+= ucb1x00-core.o

include/linux/mfd/htc-egpio.h

+/*
+ * HTC simple EGPIO irq and gpio extender
+ */
+
+#ifndef __HTC_EGPIO_H__
+#define __HTC_EGPIO_H__
+
+#include <linux/gpio.h>
+
+/* Descriptive values for all-in or all-out htc_egpio_chip descriptors. */
+#define HTC_EGPIO_OUTPUT (~0)
+#define HTC_EGPIO_INPUT  0
+
+/**
+ * struct htc_egpio_chip - descriptor to create gpio_chip for register range
+ * @reg_start: index of first register
+ * @gpio_base: gpio number of first pin in this register range
+ * @num_gpios: number of gpios in this register range, max BITS_PER_LONG
+ *    (number of registers = DIV_ROUND_UP(num_gpios, reg_width))
+ * @direction: bitfield, '0' = input, '1' = output,
+ */
+struct htc_egpio_chip {
+	int           reg_start;
+	int           gpio_base;
+	int           num_gpios;
+	unsigned long direction;
+	unsigned long initial_values;
+};
+
+/**
+ * struct htc_egpio_platform_data - description provided by the arch
+ * @irq_base: beginning of available IRQs (eg, IRQ_BOARD_START)
+ * @num_irqs: number of irqs
+ * @reg_width: number of bits per register, either 8 or 16 bit
+ * @bus_width: alignment of the registers, either 16 or 32 bit
+ * @invert_acks: set if chip requires writing '0' to ack an irq, instead of '1'
+ * @ack_register: location of the irq/ack register
+ * @chip: pointer to array of htc_egpio_chip descriptors
+ * @num_chips: number of egpio chip descriptors
+ */
+struct htc_egpio_platform_data {
+	int                   bus_width;
+	int                   reg_width;
+
+	int                   irq_base;
+	int                   num_irqs;
+	int                   invert_acks;
+	int                   ack_register;
+
+	struct htc_egpio_chip *chip;
+	int                   num_chips;
+};
+
+/* Determine the wakeup irq, to be called during early resume */
+extern int htc_egpio_get_wakeup_irq(struct device *dev);
+
+#endif