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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-sa1100/ssp.c
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/arm/mach-sa1100/ssp.c')
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1 files changed, 214 insertions, 0 deletions
diff --git a/arch/arm/mach-sa1100/ssp.c b/arch/arm/mach-sa1100/ssp.c
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+++ b/arch/arm/mach-sa1100/ssp.c
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+/*
+ * 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 irqreturn_t 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;
+
+ return status ? IRQ_HANDLED : IRQ_NONE;
+}
+
+/**
+ * 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. Wait for the SSP port to start sending
+ * the data.
+ *
+ * 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;
+
+ while (!(Ser4SSSR & SSSR_BSY))
+ cpu_relax();
+
+ 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);