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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/sbus/char/display7seg.c
Initial import
Diffstat (limited to 'drivers/sbus/char/display7seg.c')
-rw-r--r--drivers/sbus/char/display7seg.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/drivers/sbus/char/display7seg.c b/drivers/sbus/char/display7seg.c
new file mode 100644
index 000000000..33fbe8249
--- /dev/null
+++ b/drivers/sbus/char/display7seg.c
@@ -0,0 +1,272 @@
+/* display7seg.c - Driver implementation for the 7-segment display
+ * present on Sun Microsystems CP1400 and CP1500
+ *
+ * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/major.h>
+#include <linux/miscdevice.h>
+#include <linux/ioport.h> /* request_region */
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/atomic.h>
+#include <asm/uaccess.h> /* put_/get_user */
+#include <asm/io.h>
+
+#include <asm/display7seg.h>
+
+#define D7S_MINOR 193
+#define DRIVER_NAME "d7s"
+#define PFX DRIVER_NAME ": "
+
+static DEFINE_MUTEX(d7s_mutex);
+static int sol_compat = 0; /* Solaris compatibility mode */
+
+/* Solaris compatibility flag -
+ * The Solaris implementation omits support for several
+ * documented driver features (ref Sun doc 806-0180-03).
+ * By default, this module supports the documented driver
+ * abilities, rather than the Solaris implementation:
+ *
+ * 1) Device ALWAYS reverts to OBP-specified FLIPPED mode
+ * upon closure of device or module unload.
+ * 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of
+ * FLIP bit
+ *
+ * If you wish the device to operate as under Solaris,
+ * omitting above features, set this parameter to non-zero.
+ */
+module_param(sol_compat, int, 0);
+MODULE_PARM_DESC(sol_compat,
+ "Disables documented functionality omitted from Solaris driver");
+
+MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
+MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500");
+MODULE_LICENSE("GPL");
+MODULE_SUPPORTED_DEVICE("d7s");
+
+struct d7s {
+ void __iomem *regs;
+ bool flipped;
+};
+struct d7s *d7s_device;
+
+/*
+ * Register block address- see header for details
+ * -----------------------------------------
+ * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |
+ * -----------------------------------------
+ *
+ * DP - Toggles decimal point on/off
+ * ALARM - Toggles "Alarm" LED green/red
+ * FLIP - Inverts display for upside-down mounted board
+ * bits 0-4 - 7-segment display contents
+ */
+static atomic_t d7s_users = ATOMIC_INIT(0);
+
+static int d7s_open(struct inode *inode, struct file *f)
+{
+ if (D7S_MINOR != iminor(inode))
+ return -ENODEV;
+ atomic_inc(&d7s_users);
+ return 0;
+}
+
+static int d7s_release(struct inode *inode, struct file *f)
+{
+ /* Reset flipped state to OBP default only if
+ * no other users have the device open and we
+ * are not operating in solaris-compat mode
+ */
+ if (atomic_dec_and_test(&d7s_users) && !sol_compat) {
+ struct d7s *p = d7s_device;
+ u8 regval = 0;
+
+ regval = readb(p->regs);
+ if (p->flipped)
+ regval |= D7S_FLIP;
+ else
+ regval &= ~D7S_FLIP;
+ writeb(regval, p->regs);
+ }
+
+ return 0;
+}
+
+static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct d7s *p = d7s_device;
+ u8 regs = readb(p->regs);
+ int error = 0;
+ u8 ireg = 0;
+
+ if (D7S_MINOR != iminor(file_inode(file)))
+ return -ENODEV;
+
+ mutex_lock(&d7s_mutex);
+ switch (cmd) {
+ case D7SIOCWR:
+ /* assign device register values we mask-out D7S_FLIP
+ * if in sol_compat mode
+ */
+ if (get_user(ireg, (int __user *) arg)) {
+ error = -EFAULT;
+ break;
+ }
+ if (sol_compat) {
+ if (regs & D7S_FLIP)
+ ireg |= D7S_FLIP;
+ else
+ ireg &= ~D7S_FLIP;
+ }
+ writeb(ireg, p->regs);
+ break;
+
+ case D7SIOCRD:
+ /* retrieve device register values
+ * NOTE: Solaris implementation returns D7S_FLIP bit
+ * as toggled by user, even though it does not honor it.
+ * This driver will not misinform you about the state
+ * of your hardware while in sol_compat mode
+ */
+ if (put_user(regs, (int __user *) arg)) {
+ error = -EFAULT;
+ break;
+ }
+ break;
+
+ case D7SIOCTM:
+ /* toggle device mode-- flip display orientation */
+ regs ^= D7S_FLIP;
+ writeb(regs, p->regs);
+ break;
+ }
+ mutex_unlock(&d7s_mutex);
+
+ return error;
+}
+
+static const struct file_operations d7s_fops = {
+ .owner = THIS_MODULE,
+ .unlocked_ioctl = d7s_ioctl,
+ .compat_ioctl = d7s_ioctl,
+ .open = d7s_open,
+ .release = d7s_release,
+ .llseek = noop_llseek,
+};
+
+static struct miscdevice d7s_miscdev = {
+ .minor = D7S_MINOR,
+ .name = DRIVER_NAME,
+ .fops = &d7s_fops
+};
+
+static int d7s_probe(struct platform_device *op)
+{
+ struct device_node *opts;
+ int err = -EINVAL;
+ struct d7s *p;
+ u8 regs;
+
+ if (d7s_device)
+ goto out;
+
+ p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);
+ err = -ENOMEM;
+ if (!p)
+ goto out;
+
+ p->regs = of_ioremap(&op->resource[0], 0, sizeof(u8), "d7s");
+ if (!p->regs) {
+ printk(KERN_ERR PFX "Cannot map chip registers\n");
+ goto out_free;
+ }
+
+ err = misc_register(&d7s_miscdev);
+ if (err) {
+ printk(KERN_ERR PFX "Unable to acquire miscdevice minor %i\n",
+ D7S_MINOR);
+ goto out_iounmap;
+ }
+
+ /* OBP option "d7s-flipped?" is honored as default for the
+ * device, and reset default when detached
+ */
+ regs = readb(p->regs);
+ opts = of_find_node_by_path("/options");
+ if (opts &&
+ of_get_property(opts, "d7s-flipped?", NULL))
+ p->flipped = true;
+
+ if (p->flipped)
+ regs |= D7S_FLIP;
+ else
+ regs &= ~D7S_FLIP;
+
+ writeb(regs, p->regs);
+
+ printk(KERN_INFO PFX "7-Segment Display%s at [%s:0x%llx] %s\n",
+ op->dev.of_node->full_name,
+ (regs & D7S_FLIP) ? " (FLIPPED)" : "",
+ op->resource[0].start,
+ sol_compat ? "in sol_compat mode" : "");
+
+ dev_set_drvdata(&op->dev, p);
+ d7s_device = p;
+ err = 0;
+
+out:
+ return err;
+
+out_iounmap:
+ of_iounmap(&op->resource[0], p->regs, sizeof(u8));
+
+out_free:
+ goto out;
+}
+
+static int d7s_remove(struct platform_device *op)
+{
+ struct d7s *p = dev_get_drvdata(&op->dev);
+ u8 regs = readb(p->regs);
+
+ /* Honor OBP d7s-flipped? unless operating in solaris-compat mode */
+ if (sol_compat) {
+ if (p->flipped)
+ regs |= D7S_FLIP;
+ else
+ regs &= ~D7S_FLIP;
+ writeb(regs, p->regs);
+ }
+
+ misc_deregister(&d7s_miscdev);
+ of_iounmap(&op->resource[0], p->regs, sizeof(u8));
+
+ return 0;
+}
+
+static const struct of_device_id d7s_match[] = {
+ {
+ .name = "display7seg",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, d7s_match);
+
+static struct platform_driver d7s_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .of_match_table = d7s_match,
+ },
+ .probe = d7s_probe,
+ .remove = d7s_remove,
+};
+
+module_platform_driver(d7s_driver);