gpio: Add PCA9698 40-bit I2C I/O port

Signed-off-by: Dirk Eibach <eibach@gdsys.de>

1 files changed, 123 insertions, 0 deletions

diff --git a/drivers/gpio/pca9698.c b/drivers/gpio/pca9698.c
new file mode 100644
index 0000000..b946efa
--- /dev/null
+++ b/drivers/gpio/pca9698.c
@@ -0,0 +1,123 @@
+/*
+ * (C) Copyright 2011
+ * Dirk Eibach,  Guntermann & Drunck GmbH, eibach@gdsys.de
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Driver for NXP's pca9698 40 bit I2C gpio expander
+ */
+
+#include <common.h>
+#include <i2c.h>
+#include <pca9698.h>
+
+/*
+ * The pca9698 registers
+ */
+
+#define PCA9698_REG_INPUT		0x00
+#define PCA9698_REG_OUTPUT		0x08
+#define PCA9698_REG_POLARITY		0x10
+#define PCA9698_REG_CONFIG		0x18
+
+#define PCA9698_BUFFER_SIZE		5
+
+static int pca9698_read40(u8 chip, u8 offset, u8 *buffer)
+{
+	u8 command = offset | 0x80;  /* autoincrement */
+
+	return i2c_read(chip, command, 1, buffer, PCA9698_BUFFER_SIZE);
+}
+
+static int pca9698_write40(u8 chip, u8 offset, u8 *buffer)
+{
+	u8 command = offset | 0x80;  /* autoincrement */
+
+	return i2c_write(chip, command, 1, buffer, PCA9698_BUFFER_SIZE);
+}
+
+static void pca9698_set_bit(unsigned gpio, u8 *buffer, unsigned value)
+{
+	unsigned byte = gpio / 8;
+	unsigned bit = gpio % 8;
+
+	if (value)
+		buffer[byte] |= (1 << bit);
+	else
+		buffer[byte] &= ~(1 << bit);
+}
+
+int pca9698_direction_input(u8 chip, unsigned offset)
+{
+	u8 data[PCA9698_BUFFER_SIZE];
+	int res;
+
+	res = pca9698_read40(chip, PCA9698_REG_CONFIG, data);
+	if (res)
+		return res;
+
+	pca9698_set_bit(offset, data, 1);
+	return pca9698_write40(chip, PCA9698_REG_CONFIG, data);
+}
+
+int pca9698_direction_output(u8 chip, unsigned offset)
+{
+	u8 data[PCA9698_BUFFER_SIZE];
+	int res;
+
+	res = pca9698_read40(chip, PCA9698_REG_CONFIG, data);
+	if (res)
+		return res;
+
+	pca9698_set_bit(offset, data, 0);
+	return pca9698_write40(chip, PCA9698_REG_CONFIG, data);
+}
+
+int pca9698_get_input(u8 chip, unsigned offset)
+{
+	unsigned config_byte = offset / 8;
+	unsigned config_bit = offset % 8;
+	unsigned value;
+	u8 data[PCA9698_BUFFER_SIZE];
+	int res;
+
+	res = pca9698_read40(chip, PCA9698_REG_INPUT, data);
+	if (res)
+		return -1;
+
+	value = data[config_byte] & (1 << config_bit);
+
+	return !!value;
+}
+
+int pca9698_set_output(u8 chip, unsigned offset, int value)
+{
+	u8 data[PCA9698_BUFFER_SIZE];
+	int res;
+
+	res = pca9698_read40(chip, PCA9698_REG_OUTPUT, data);
+	if (res)
+		return res;
+
+	memset(data, sizeof(data), 0);
+	pca9698_set_bit(offset, data, value);
+	return pca9698_write40(chip, PCA9698_REG_OUTPUT, data);
+}