SPI: tle620x power switch driver

Add support for the Infineon TLE62x0 series of low-side driver chips, such
as the TLE6220 or TLE6230. These can be viewed as output GPIOs specialized
for power switching applications. The driver provides a userspace
interface to those GPIOs, and to the switch status they provide.

Signed-off-by: Ben Dooks <[e-mail]>
Signed-off-by: David Brownell <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/spi/Kconfig

···
 	  Note that this application programming interface is EXPERIMENTAL
 	  and hence SUBJECT TO CHANGE WITHOUT NOTICE while it stabilizes.
 
+config SPI_TLE62X0
+	tristate "Infineon TLE62X0 (for power switching)"
+	depends on SPI_MASTER && SYSFS
+	help
+	  SPI driver for Infineon TLE62X0 series line driver chips,
+	  such as the TLE6220, TLE6230 and TLE6240.  This provides a
+	  sysfs interface, with each line presented as a kind of GPIO
+	  exposing both switch control and diagnostic feedback.
+
 #
 # Add new SPI protocol masters in alphabetical order above this line
 #

drivers/spi/Makefile

···
 # SPI protocol drivers (device/link on bus)
 obj-$(CONFIG_SPI_AT25)		+= at25.o
 obj-$(CONFIG_SPI_SPIDEV)	+= spidev.o
+obj-$(CONFIG_SPI_TLE62X0)	+= tle62x0.o
 # 	... add above this line ...
 
 # SPI slave controller drivers (upstream link)

drivers/spi/tle62x0.c

···
+/*
+ * tle62x0.c -- support Infineon TLE62x0 driver chips
+ *
+ * Copyright (c) 2007 Simtec Electronics
+ *	Ben Dooks, <[e-mail]>
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/tle62x0.h>
+
+
+#define CMD_READ	0x00
+#define CMD_SET		0xff
+
+#define DIAG_NORMAL	0x03
+#define DIAG_OVERLOAD	0x02
+#define DIAG_OPEN	0x01
+#define DIAG_SHORTGND	0x00
+
+struct tle62x0_state {
+	struct spi_device	*us;
+	struct mutex		lock;
+	unsigned int		nr_gpio;
+	unsigned int		gpio_state;
+
+	unsigned char		tx_buff[4];
+	unsigned char		rx_buff[4];
+};
+
+static int to_gpio_num(struct device_attribute *attr);
+
+static inline int tle62x0_write(struct tle62x0_state *st)
+{
+	unsigned char *buff = st->tx_buff;
+	unsigned int gpio_state = st->gpio_state;
+
+	buff[0] = CMD_SET;
+
+	if (st->nr_gpio == 16) {
+		buff[1] = gpio_state >> 8;
+		buff[2] = gpio_state;
+	} else {
+		buff[1] = gpio_state;
+	}
+
+	dev_dbg(&st->us->dev, "buff %02x,%02x,%02x\n",
+		buff[0], buff[1], buff[2]);
+
+	return spi_write(st->us, buff, (st->nr_gpio == 16) ? 3 : 2);
+}
+
+static inline int tle62x0_read(struct tle62x0_state *st)
+{
+	unsigned char *txbuff = st->tx_buff;
+	struct spi_transfer xfer = {
+		.tx_buf		= txbuff,
+		.rx_buf		= st->rx_buff,
+		.len		= (st->nr_gpio * 2) / 8,
+	};
+	struct spi_message msg;
+
+	txbuff[0] = CMD_READ;
+	txbuff[1] = 0x00;
+	txbuff[2] = 0x00;
+	txbuff[3] = 0x00;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer, &msg);
+
+	return spi_sync(st->us, &msg);
+}
+
+static unsigned char *decode_fault(unsigned int fault_code)
+{
+	fault_code &= 3;
+
+	switch (fault_code) {
+	case DIAG_NORMAL:
+		return "N";
+	case DIAG_OVERLOAD:
+		return "V";
+	case DIAG_OPEN:
+		return "O";
+	case DIAG_SHORTGND:
+		return "G";
+	}
+
+	return "?";
+}
+
+static ssize_t tle62x0_status_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct tle62x0_state *st = dev_get_drvdata(dev);
+	char *bp = buf;
+	unsigned char *buff = st->rx_buff;
+	unsigned long fault = 0;
+	int ptr;
+	int ret;
+
+	mutex_lock(&st->lock);
+	ret = tle62x0_read(st);
+
+	dev_dbg(dev, "tle62x0_read() returned %d\n", ret);
+
+	for (ptr = 0; ptr < (st->nr_gpio * 2)/8; ptr += 1) {
+		fault <<= 8;
+		fault  |= ((unsigned long)buff[ptr]);
+
+		dev_dbg(dev, "byte %d is %02x\n", ptr, buff[ptr]);
+	}
+
+	for (ptr = 0; ptr < st->nr_gpio; ptr++) {
+		bp += sprintf(bp, "%s ", decode_fault(fault >> (ptr * 2)));
+	}
+
+	*bp++ = '\n';
+
+	mutex_unlock(&st->lock);
+	return bp - buf;
+}
+
+static DEVICE_ATTR(status_show, S_IRUGO, tle62x0_status_show, NULL);
+
+static ssize_t tle62x0_gpio_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct tle62x0_state *st = dev_get_drvdata(dev);
+	int gpio_num = to_gpio_num(attr);
+	int value;
+
+	mutex_lock(&st->lock);
+	value = (st->gpio_state >> gpio_num) & 1;
+	mutex_unlock(&st->lock);
+
+	return snprintf(buf, PAGE_SIZE, "%d", value);
+}
+
+static ssize_t tle62x0_gpio_store(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t len)
+{
+	struct tle62x0_state *st = dev_get_drvdata(dev);
+	int gpio_num = to_gpio_num(attr);
+	unsigned long val;
+	char *endp;
+
+	val = simple_strtoul(buf, &endp, 0);
+	if (buf == endp)
+		return -EINVAL;
+
+	dev_dbg(dev, "setting gpio %d to %ld\n", gpio_num, val);
+
+	mutex_lock(&st->lock);
+
+	if (val)
+		st->gpio_state |= 1 << gpio_num;
+	else
+		st->gpio_state &= ~(1 << gpio_num);
+
+	tle62x0_write(st);
+	mutex_unlock(&st->lock);
+
+	return len;
+}
+
+static DEVICE_ATTR(gpio1, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio2, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio3, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio4, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio5, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio6, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio7, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio8, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio9, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio10, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio11, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio12, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio13, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio14, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio15, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+static DEVICE_ATTR(gpio16, S_IWUSR|S_IRUGO,
+		tle62x0_gpio_show, tle62x0_gpio_store);
+
+static struct device_attribute *gpio_attrs[] = {
+	[0]		= &dev_attr_gpio1,
+	[1]		= &dev_attr_gpio2,
+	[2]		= &dev_attr_gpio3,
+	[3]		= &dev_attr_gpio4,
+	[4]		= &dev_attr_gpio5,
+	[5]		= &dev_attr_gpio6,
+	[6]		= &dev_attr_gpio7,
+	[7]		= &dev_attr_gpio8,
+	[8]		= &dev_attr_gpio9,
+	[9]		= &dev_attr_gpio10,
+	[10]		= &dev_attr_gpio11,
+	[11]		= &dev_attr_gpio12,
+	[12]		= &dev_attr_gpio13,
+	[13]		= &dev_attr_gpio14,
+	[14]		= &dev_attr_gpio15,
+	[15]		= &dev_attr_gpio16
+};
+
+static int to_gpio_num(struct device_attribute *attr)
+{
+	int ptr;
+
+	for (ptr = 0; ptr < ARRAY_SIZE(gpio_attrs); ptr++) {
+		if (gpio_attrs[ptr] == attr)
+			return ptr;
+	}
+
+	return -1;
+}
+
+static int __devinit tle62x0_probe(struct spi_device *spi)
+{
+	struct tle62x0_state *st;
+	struct tle62x0_pdata *pdata;
+	int ptr;
+	int ret;
+
+	pdata = spi->dev.platform_data;
+	if (pdata == NULL) {
+		dev_err(&spi->dev, "no device data specified\n");
+		return -EINVAL;
+	}
+
+	st = kzalloc(sizeof(struct tle62x0_state), GFP_KERNEL);
+	if (st == NULL) {
+		dev_err(&spi->dev, "no memory for device state\n");
+		return -ENOMEM;
+	}
+
+	st->us = spi;
+	st->nr_gpio = pdata->gpio_count;
+	st->gpio_state = pdata->init_state;
+
+	mutex_init(&st->lock);
+
+	ret = device_create_file(&spi->dev, &dev_attr_status_show);
+	if (ret) {
+		dev_err(&spi->dev, "cannot create status attribute\n");
+		goto err_status;
+	}
+
+	for (ptr = 0; ptr < pdata->gpio_count; ptr++) {
+		ret = device_create_file(&spi->dev, gpio_attrs[ptr]);
+		if (ret) {
+			dev_err(&spi->dev, "cannot create gpio attribute\n");
+			goto err_gpios;
+		}
+	}
+
+	/* tle62x0_write(st); */
+	spi_set_drvdata(spi, st);
+	return 0;
+
+ err_gpios:
+	for (; ptr > 0; ptr--)
+		device_remove_file(&spi->dev, gpio_attrs[ptr]);
+
+	device_remove_file(&spi->dev, &dev_attr_status_show);
+
+ err_status:
+	kfree(st);
+	return ret;
+}
+
+static int __devexit tle62x0_remove(struct spi_device *spi)
+{
+	struct tle62x0_state *st = spi_get_drvdata(spi);
+	int ptr;
+
+	for (ptr = 0; ptr < st->nr_gpio; ptr++)
+		device_remove_file(&spi->dev, gpio_attrs[ptr]);
+
+	kfree(st);
+	return 0;
+}
+
+static struct spi_driver tle62x0_driver = {
+	.driver = {
+		.name	= "tle62x0",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= tle62x0_probe,
+	.remove		= __devexit_p(tle62x0_remove),
+};
+
+static __init int tle62x0_init(void)
+{
+	return spi_register_driver(&tle62x0_driver);
+}
+
+static __exit void tle62x0_exit(void)
+{
+	spi_unregister_driver(&tle62x0_driver);
+}
+
+module_init(tle62x0_init);
+module_exit(tle62x0_exit);
+
+MODULE_AUTHOR("Ben Dooks <[e-mail]>");
+MODULE_DESCRIPTION("TLE62x0 SPI driver");
+MODULE_LICENSE("GPL v2");

include/linux/spi/tle62x0.h

···
+/*
+ * tle62x0.h - platform glue to Infineon TLE62x0 driver chips
+ *
+ * Copyright 2007 Simtec Electronics
+ *	Ben Dooks <[e-mail]>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+struct tle62x0_pdata {
+	unsigned int		init_state;
+	unsigned int		gpio_count;
+};