[ARM] Add generic SSP "PIO" mode driver

Add SSP PIO driver - provides an interface for talking to
microcontrollers and such like connected to the SA1110's
SSP port.

arch/arm/mach-sa1100/Kconfig

@@ -326,6 +326,15 @@ config SA1100_STORK
 #	help
 #	  :: write me ::
 
+config SA1100_SSP
+	tristate "Generic PIO SSP"
+	depends on ARCH_SA1100
+	help
+	  Say Y here to enable support for the generic PIO SSP driver.
+	  This isn't for audio support, but for attached sensors and
+	  other devices, eg for BadgePAD 4 sensor support, or Jornada
+	  720 touchscreen support.
+
 config SA1100_USB
 	tristate "SA1100 USB function support"
 	depends on ARCH_SA1100

arch/arm/mach-sa1100/Makefile

@@ -92,3 +92,4 @@ obj-$(CONFIG_LEDS) += $(led-y)
 
 # Miscelaneous functions
 obj-$(CONFIG_PM)			+= pm.o sleep.o
+obj-$(CONFIG_SA1100_SSP)		+= ssp.o

arch/arm/mach-sa1100/ssp.c

+/*
+ *  linux/arch/arm/mach-sa1100/ssp.c
+ *
+ *  Copyright (C) 2003 Russell King.
+ *
+ * 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.
+ *
+ *  Generic SSP driver.  This provides the generic core for simple
+ *  IO-based SSP applications.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/hardware.h>
+#include <asm/hardware/ssp.h>
+
+static void ssp_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	unsigned int status = Ser4SSSR;
+
+	if (status & SSSR_ROR) {
+		printk(KERN_WARNING "SSP: receiver overrun\n");
+	}
+
+	Ser4SSSR = SSSR_ROR;
+}
+
+/**
+ * ssp_write_word - write a word to the SSP port
+ * @data: 16-bit, MSB justified data to write.
+ *
+ * Wait for a free entry in the SSP transmit FIFO, and write a data
+ * word to the SSP port.
+ *
+ * The caller is expected to perform the necessary locking.
+ *
+ * Returns:
+ *   %-ETIMEDOUT	timeout occurred (for future)
+ *   0			success
+ */
+int ssp_write_word(u16 data)
+{
+	while (!(Ser4SSSR & SSSR_TNF))
+		cpu_relax();
+
+	Ser4SSDR = data;
+
+	return 0;
+}
+
+/**
+ * ssp_read_word - read a word from the SSP port
+ *
+ * Wait for a data word in the SSP receive FIFO, and return the
+ * received data.  Data is LSB justified.
+ *
+ * Note: Currently, if data is not expected to be received, this
+ * function will wait for ever.
+ *
+ * The caller is expected to perform the necessary locking.
+ *
+ * Returns:
+ *   %-ETIMEDOUT	timeout occurred (for future)
+ *   16-bit data	success
+ */
+int ssp_read_word(void)
+{
+	while (!(Ser4SSSR & SSSR_RNE))
+		cpu_relax();
+
+	return Ser4SSDR;
+}
+
+/**
+ * ssp_flush - flush the transmit and receive FIFOs
+ *
+ * Wait for the SSP to idle, and ensure that the receive FIFO
+ * is empty.
+ *
+ * The caller is expected to perform the necessary locking.
+ */
+void ssp_flush(void)
+{
+	do {
+		while (Ser4SSSR & SSSR_RNE) {
+			(void) Ser4SSDR;
+		}
+	} while (Ser4SSSR & SSSR_BSY);
+}
+
+/**
+ * ssp_enable - enable the SSP port
+ *
+ * Turn on the SSP port.
+ */
+void ssp_enable(void)
+{
+	Ser4SSCR0 |= SSCR0_SSE;
+}
+
+/**
+ * ssp_disable - shut down the SSP port
+ *
+ * Turn off the SSP port, optionally powering it down.
+ */
+void ssp_disable(void)
+{
+	Ser4SSCR0 &= ~SSCR0_SSE;
+}
+
+/**
+ * ssp_save_state - save the SSP configuration
+ * @ssp: pointer to structure to save SSP configuration
+ *
+ * Save the configured SSP state for suspend.
+ */
+void ssp_save_state(struct ssp_state *ssp)
+{
+	ssp->cr0 = Ser4SSCR0;
+	ssp->cr1 = Ser4SSCR1;
+
+	Ser4SSCR0 &= ~SSCR0_SSE;
+}
+
+/**
+ * ssp_restore_state - restore a previously saved SSP configuration
+ * @ssp: pointer to configuration saved by ssp_save_state
+ *
+ * Restore the SSP configuration saved previously by ssp_save_state.
+ */
+void ssp_restore_state(struct ssp_state *ssp)
+{
+	Ser4SSSR = SSSR_ROR;
+
+	Ser4SSCR0 = ssp->cr0 & ~SSCR0_SSE;
+	Ser4SSCR1 = ssp->cr1;
+	Ser4SSCR0 = ssp->cr0;
+}
+
+/**
+ * ssp_init - setup the SSP port
+ *
+ * initialise and claim resources for the SSP port.
+ *
+ * Returns:
+ *   %-ENODEV	if the SSP port is unavailable
+ *   %-EBUSY	if the resources are already in use
+ *   %0		on success
+ */
+int ssp_init(void)
+{
+	int ret;
+
+	if (!(PPAR & PPAR_SPR) && (Ser4MCCR0 & MCCR0_MCE))
+		return -ENODEV;
+
+	if (!request_mem_region(__PREG(Ser4SSCR0), 0x18, "SSP")) {
+		return -EBUSY;
+	}
+
+	Ser4SSSR = SSSR_ROR;
+
+	ret = request_irq(IRQ_Ser4SSP, ssp_interrupt, 0, "SSP", NULL);
+	if (ret)
+		goto out_region;
+
+	return 0;
+
+ out_region:
+	release_mem_region(__PREG(Ser4SSCR0), 0x18);
+	return ret;
+}
+
+/**
+ * ssp_exit - undo the effects of ssp_init
+ *
+ * release and free resources for the SSP port.
+ */
+void ssp_exit(void)
+{
+	Ser4SSCR0 &= ~SSCR0_SSE;
+
+	free_irq(IRQ_Ser4SSP, NULL);
+	release_mem_region(__PREG(Ser4SSCR0), 0x18);
+}
+
+MODULE_AUTHOR("Russell King");
+MODULE_DESCRIPTION("SA11x0 SSP PIO driver");
+MODULE_LICENSE("GPL");
+
+EXPORT_SYMBOL(ssp_write_word);
+EXPORT_SYMBOL(ssp_read_word);
+EXPORT_SYMBOL(ssp_flush);
+EXPORT_SYMBOL(ssp_enable);
+EXPORT_SYMBOL(ssp_disable);
+EXPORT_SYMBOL(ssp_save_state);
+EXPORT_SYMBOL(ssp_restore_state);
+EXPORT_SYMBOL(ssp_init);
+EXPORT_SYMBOL(ssp_exit);