[ARM] 4506/1: HP Jornada 7XX: Addition of SSP Platform Driver

These patches add full SSP/MCU support for the HP Jornada 720
machine.  Its needed to handle keyboard, touchscreen, battery
and backlight/lcd.

The main driver exports functions and the header file exports
the command values. When talking to the MCU the general procedure
is to start MCU, send command (using ssp_inout(command)), the
proper reply is always TXDUMMY.  After receiving TXDUMMY you can
send the value you wish pushed (for example brightness level).
End with ssp_end() so the spinlock gets unlocked.

Drivers using this havent been implemented yet, but will shortly.

Signed-off-by: Kristoffer Ericson <Kristoffer.ericson@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 201 insertions, 0 deletions

diff --git a/arch/arm/mach-sa1100/jornada720_ssp.c b/arch/arm/mach-sa1100/jornada720_ssp.c
new file mode 100644
index 000000000000..0a45e1ac8ad6
--- /dev/null
+++ b/arch/arm/mach-sa1100/jornada720_ssp.c
@@ -0,0 +1,201 @@
+/**
+ *  arch/arm/mac-sa1100/jornada720_ssp.c
+ *
+ *  Copyright (C) 2006/2007 Kristoffer Ericson <Kristoffer.Ericson@gmail.com>
+ *   Copyright (C) 2006 Filip Zyzniewski <filip.zyzniewski@tefnet.pl>
+ *
+ * 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.
+ *
+ *  SSP driver for the HP Jornada 710/720/728
+ */
+
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <asm/hardware.h>
+#include <asm/hardware/ssp.h>
+#include <asm/arch/jornada720.h>
+
+static DEFINE_SPINLOCK(jornada_ssp_lock);
+static unsigned long jornada_ssp_flags;
+
+/**
+ * jornada_ssp_reverse - reverses input byte
+ *
+ * we need to reverse all data we recieve from the mcu due to its physical location
+ * returns : 01110111 -> 11101110
+ */
+u8 inline jornada_ssp_reverse(u8 byte)
+{
+	return
+		((0x80 & byte) >> 7) |
+		((0x40 & byte) >> 5) |
+		((0x20 & byte) >> 3) |
+		((0x10 & byte) >> 1) |
+		((0x08 & byte) << 1) |
+		((0x04 & byte) << 3) |
+		((0x02 & byte) << 5) |
+		((0x01 & byte) << 7);
+};
+EXPORT_SYMBOL(jornada_ssp_reverse);
+
+/**
+ * jornada_ssp_byte - waits for ready ssp bus and sends byte
+ *
+ * waits for fifo buffer to clear and then transmits, if it doesn't then we will
+ * timeout after <timeout> rounds. Needs mcu running before its called.
+ *
+ * returns : %mcu output on success
+ *	   : %-ETIMEOUT on timeout
+ */
+int jornada_ssp_byte(u8 byte)
+{
+	int timeout = 400000;
+	u16 ret;
+
+	while ((GPLR & GPIO_GPIO10)) {
+		if (!--timeout) {
+			printk(KERN_WARNING "SSP: timeout while waiting for transmit\n");
+			return -ETIMEDOUT;
+		}
+		cpu_relax();
+	}
+
+	ret = jornada_ssp_reverse(byte) << 8;
+
+	ssp_write_word(ret);
+	ssp_read_word(&ret);
+
+	return jornada_ssp_reverse(ret);
+};
+EXPORT_SYMBOL(jornada_ssp_byte);
+
+/**
+ * jornada_ssp_inout - decide if input is command or trading byte
+ *
+ * returns : (jornada_ssp_byte(byte)) on success
+ *         : %-ETIMEOUT on timeout failure
+ */
+int jornada_ssp_inout(u8 byte)
+{
+	int ret, i;
+
+	/* true means command byte */
+	if (byte != TXDUMMY) {
+		ret = jornada_ssp_byte(byte);
+		/* Proper return to commands is TxDummy */
+		if (ret != TXDUMMY) {
+			for (i = 0; i < 256; i++)/* flushing bus */
+				if (jornada_ssp_byte(TXDUMMY) == -1)
+					break;
+			return -ETIMEDOUT;
+		}
+	} else /* Exchange TxDummy for data */
+		ret = jornada_ssp_byte(TXDUMMY);
+
+	return ret;
+};
+EXPORT_SYMBOL(jornada_ssp_inout);
+
+/**
+ * jornada_ssp_start - enable mcu
+ *
+ */
+int jornada_ssp_start()
+{
+	spin_lock_irqsave(&jornada_ssp_lock, jornada_ssp_flags);
+	GPCR = GPIO_GPIO25;
+	udelay(50);
+	return 0;
+};
+EXPORT_SYMBOL(jornada_ssp_start);
+
+/**
+ * jornada_ssp_end - disable mcu and turn off lock
+ *
+ */
+int jornada_ssp_end()
+{
+	GPSR = GPIO_GPIO25;
+	spin_unlock_irqrestore(&jornada_ssp_lock, jornada_ssp_flags);
+	return 0;
+};
+EXPORT_SYMBOL(jornada_ssp_end);
+
+static int __init jornada_ssp_probe(struct platform_device *dev)
+{
+	int ret;
+
+	GPSR = GPIO_GPIO25;
+
+	ret = ssp_init();
+
+	/* worked fine, lets not bother with anything else */
+	if (!ret) {
+		printk(KERN_INFO "SSP: device initialized with irq\n");
+		return ret;
+	}
+
+	printk(KERN_WARNING "SSP: initialization failed, trying non-irq solution \n");
+
+	/* init of Serial 4 port */
+	Ser4MCCR0 = 0;
+	Ser4SSCR0 = 0x0387;
+	Ser4SSCR1 = 0x18;
+
+	/* clear out any left over data */
+	ssp_flush();
+
+	/* enable MCU */
+	jornada_ssp_start();
+
+	/* see if return value makes sense */
+	ret = jornada_ssp_inout(GETBRIGHTNESS);
+
+	/* seems like it worked, just feed it with TxDummy to get rid of data */
+	if (ret == TxDummy)
+		jornada_ssp_inout(TXDUMMY);
+
+	jornada_ssp_end();
+
+	/* failed, lets just kill everything */
+	if (ret == -ETIMEDOUT) {
+		printk(KERN_WARNING "SSP: attempts failed, bailing\n");
+		ssp_exit();
+		return -ENODEV;
+	}
+
+	/* all fine */
+	printk(KERN_INFO "SSP: device initialized\n");
+	return 0;
+};
+
+static int jornada_ssp_remove(struct platform_device *dev)
+{
+	/* Note that this doesnt actually remove the driver, since theres nothing to remove
+	 * It just makes sure everything is turned off */
+	GPSR = GPIO_GPIO25;
+	ssp_exit();
+	return 0;
+};
+
+struct platform_driver jornadassp_driver = {
+	.probe	= jornada_ssp_probe,
+	.remove	= jornada_ssp_remove,
+	.driver	= {
+		.name	= "jornada_ssp",
+	},
+};
+
+static int __init jornada_ssp_init(void)
+{
+	return platform_driver_register(&jornadassp_driver);
+}