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 <ben-linux@fluff.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 338 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 8ce16a0b8a50..a49270eae660 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -198,6 +198,15 @@ config SPI_SPIDEV
           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
 #
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 89293338f20c..d9bd7f605d6a 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_SPI_S3C24XX)		+= spi_s3c24xx.o
 # SPI protocol drivers (device/link on bus)
 obj-$(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)
diff --git a/drivers/spi/tle62x0.c b/drivers/spi/tle62x0.c
new file mode 100644
index 000000000000..6da58ca48b33
--- /dev/null
+++ b/drivers/spi/tle62x0.c
@@ -0,0 +1,328 @@
+/*
+ * tle62x0.c -- support Infineon TLE62x0 driver chips
+ *
+ * Copyright (c) 2007 Simtec Electronics
+ *      Ben Dooks, <ben@simtec.co.uk>
+ *
+ * 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 <ben@simtec.co.uk>");
+MODULE_DESCRIPTION("TLE62x0 SPI driver");
+MODULE_LICENSE("GPL v2");