--- /dev/null
+/*
+ * 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 <linux/io.h>
+
+#include <mach/hardware.h>
+#include <mach/irqs.h>
+#include <asm/hardware/ssp.h>
+
+#define TIMEOUT 100000
+
+static irqreturn_t ssp_interrupt(int irq, void *dev_id)
+{
+ 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
+ * 0 success
+ */
+int ssp_write_word(u16 data)
+{
+ int timeout = TIMEOUT;
+
+ while (!(Ser4SSSR & SSSR_TNF)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
+ cpu_relax();
+ }
+
+ Ser4SSDR = data;
+
+ timeout = TIMEOUT;
+ while (!(Ser4SSSR & SSSR_BSY)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
+ 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
+ * 16-bit data success
+ */
+int ssp_read_word(u16 *data)
+{
+ int timeout = TIMEOUT;
+
+ while (!(Ser4SSSR & SSSR_RNE)) {
+ if (!--timeout)
+ return -ETIMEDOUT;
+ cpu_relax();
+ }
+
+ *data = (u16)Ser4SSDR;
+
+ return 0;
+}
+
+/**
+ * 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.
+ *
+ * Returns:
+ * %-ETIMEDOUT timeout occurred
+ * 0 success
+ */
+int ssp_flush(void)
+{
+ int timeout = TIMEOUT * 2;
+
+ do {
+ while (Ser4SSSR & SSSR_RNE) {
+ if (!--timeout)
+ return -ETIMEDOUT;
+ (void) Ser4SSDR;
+ }
+ if (!--timeout)
+ return -ETIMEDOUT;
+ } while (Ser4SSSR & SSSR_BSY);
+
+ return 0;
+}
+
+/**
+ * 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);
Code Review / kvmfornfv.git / blobdiff