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-rw-r--r--arch/arm/mach-pxa/ssp.c363
1 files changed, 363 insertions, 0 deletions
diff --git a/arch/arm/mach-pxa/ssp.c b/arch/arm/mach-pxa/ssp.c
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+/*
+ * linux/arch/arm/mach-pxa/ssp.c
+ *
+ * based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
+ *
+ * Copyright (C) 2003 Russell King.
+ * Copyright (C) 2003 Wolfson Microelectronics PLC
+ *
+ * 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.
+ *
+ * PXA2xx SSP driver. This provides the generic core for simple
+ * IO-based SSP applications and allows easy port setup for DMA access.
+ *
+ * Author: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
+ *
+ * Revision history:
+ * 22nd Aug 2003 Initial version.
+ * 20th Dec 2004 Added ssp_config for changing port config without
+ * closing the port.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/slab.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/arch/ssp.h>
+#include <asm/arch/pxa-regs.h>
+
+#define PXA_SSP_PORTS 3
+
+static DECLARE_MUTEX(sem);
+static int use_count[PXA_SSP_PORTS] = {0, 0, 0};
+
+static irqreturn_t ssp_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+ struct ssp_dev *dev = (struct ssp_dev*) dev_id;
+ unsigned int status = SSSR_P(dev->port);
+
+ SSSR_P(dev->port) = status; /* clear status bits */
+
+ if (status & SSSR_ROR)
+ printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);
+
+ if (status & SSSR_TUR)
+ printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);
+
+ if (status & SSSR_BCE)
+ printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * ssp_write_word - write a word to the SSP port
+ * @data: 32-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(struct ssp_dev *dev, u32 data)
+{
+ while (!(SSSR_P(dev->port) & SSSR_TNF))
+ cpu_relax();
+
+ SSDR_P(dev->port) = 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)
+ * 32-bit data success
+ */
+int ssp_read_word(struct ssp_dev *dev)
+{
+ while (!(SSSR_P(dev->port) & SSSR_RNE))
+ cpu_relax();
+
+ return SSDR_P(dev->port);
+}
+
+/**
+ * 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(struct ssp_dev *dev)
+{
+ do {
+ while (SSSR_P(dev->port) & SSSR_RNE) {
+ (void) SSDR_P(dev->port);
+ }
+ } while (SSSR_P(dev->port) & SSSR_BSY);
+}
+
+/**
+ * ssp_enable - enable the SSP port
+ *
+ * Turn on the SSP port.
+ */
+void ssp_enable(struct ssp_dev *dev)
+{
+ SSCR0_P(dev->port) |= SSCR0_SSE;
+}
+
+/**
+ * ssp_disable - shut down the SSP port
+ *
+ * Turn off the SSP port, optionally powering it down.
+ */
+void ssp_disable(struct ssp_dev *dev)
+{
+ SSCR0_P(dev->port) &= ~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_dev *dev, struct ssp_state *ssp)
+{
+ ssp->cr0 = SSCR0_P(dev->port);
+ ssp->cr1 = SSCR1_P(dev->port);
+ ssp->to = SSTO_P(dev->port);
+ ssp->psp = SSPSP_P(dev->port);
+
+ SSCR0_P(dev->port) &= ~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_dev *dev, struct ssp_state *ssp)
+{
+ SSSR_P(dev->port) = SSSR_ROR | SSSR_TUR | SSSR_BCE;
+
+ SSCR0_P(dev->port) = ssp->cr0 & ~SSCR0_SSE;
+ SSCR1_P(dev->port) = ssp->cr1;
+ SSTO_P(dev->port) = ssp->to;
+ SSPSP_P(dev->port) = ssp->psp;
+
+ SSCR0_P(dev->port) = ssp->cr0;
+}
+
+/**
+ * ssp_config - configure SSP port settings
+ * @mode: port operating mode
+ * @flags: port config flags
+ * @psp_flags: port PSP config flags
+ * @speed: port speed
+ *
+ * Port MUST be disabled by ssp_disable before making any config changes.
+ */
+int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
+{
+ dev->mode = mode;
+ dev->flags = flags;
+ dev->psp_flags = psp_flags;
+ dev->speed = speed;
+
+ /* set up port type, speed, port settings */
+ SSCR0_P(dev->port) = (dev->speed | dev->mode);
+ SSCR1_P(dev->port) = dev->flags;
+ SSPSP_P(dev->port) = dev->psp_flags;
+
+ return 0;
+}
+
+/**
+ * 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(struct ssp_dev *dev, u32 port)
+{
+ int ret, irq;
+
+ if (port > PXA_SSP_PORTS || port == 0)
+ return -ENODEV;
+
+ down(&sem);
+ if (use_count[port - 1]) {
+ up(&sem);
+ return -EBUSY;
+ }
+ use_count[port - 1]++;
+
+ if (!request_mem_region(__PREG(SSCR0_P(port)), 0x2c, "SSP")) {
+ use_count[port - 1]--;
+ up(&sem);
+ return -EBUSY;
+ }
+
+ switch (port) {
+ case 1:
+ irq = IRQ_SSP;
+ break;
+#if defined (CONFIG_PXA27x)
+ case 2:
+ irq = IRQ_SSP2;
+ break;
+ case 3:
+ irq = IRQ_SSP3;
+ break;
+#else
+ case 2:
+ irq = IRQ_NSSP;
+ break;
+ case 3:
+ irq = IRQ_ASSP;
+ break;
+#endif
+ default:
+ return -ENODEV;
+ }
+
+ dev->port = port;
+
+ ret = request_irq(irq, ssp_interrupt, 0, "SSP", dev);
+ if (ret)
+ goto out_region;
+
+ /* turn on SSP port clock */
+ switch (dev->port) {
+#if defined (CONFIG_PXA27x)
+ case 1:
+ pxa_set_cken(CKEN23_SSP1, 1);
+ break;
+ case 2:
+ pxa_set_cken(CKEN3_SSP2, 1);
+ break;
+ case 3:
+ pxa_set_cken(CKEN4_SSP3, 1);
+ break;
+#else
+ case 1:
+ pxa_set_cken(CKEN3_SSP, 1);
+ break;
+ case 2:
+ pxa_set_cken(CKEN9_NSSP, 1);
+ break;
+ case 3:
+ pxa_set_cken(CKEN10_ASSP, 1);
+ break;
+#endif
+ }
+
+ up(&sem);
+ return 0;
+
+out_region:
+ release_mem_region(__PREG(SSCR0_P(port)), 0x2c);
+ use_count[port - 1]--;
+ up(&sem);
+ return ret;
+}
+
+/**
+ * ssp_exit - undo the effects of ssp_init
+ *
+ * release and free resources for the SSP port.
+ */
+void ssp_exit(struct ssp_dev *dev)
+{
+ int irq;
+
+ down(&sem);
+ SSCR0_P(dev->port) &= ~SSCR0_SSE;
+
+ /* find irq, save power and turn off SSP port clock */
+ switch (dev->port) {
+#if defined (CONFIG_PXA27x)
+ case 1:
+ irq = IRQ_SSP;
+ pxa_set_cken(CKEN23_SSP1, 0);
+ break;
+ case 2:
+ irq = IRQ_SSP2;
+ pxa_set_cken(CKEN3_SSP2, 0);
+ break;
+ case 3:
+ irq = IRQ_SSP3;
+ pxa_set_cken(CKEN4_SSP3, 0);
+ break;
+#else
+ case 1:
+ irq = IRQ_SSP;
+ pxa_set_cken(CKEN3_SSP, 0);
+ break;
+ case 2:
+ irq = IRQ_NSSP;
+ pxa_set_cken(CKEN9_NSSP, 0);
+ break;
+ case 3:
+ irq = IRQ_ASSP;
+ pxa_set_cken(CKEN10_ASSP, 0);
+ break;
+#endif
+ default:
+ printk(KERN_WARNING "SSP: tried to close invalid port\n");
+ return;
+ }
+
+ free_irq(irq, dev);
+ release_mem_region(__PREG(SSCR0_P(dev->port)), 0x2c);
+ use_count[dev->port - 1]--;
+ up(&sem);
+}
+
+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);
+EXPORT_SYMBOL(ssp_config);
+
+MODULE_DESCRIPTION("PXA SSP driver");
+MODULE_AUTHOR("Liam Girdwood");
+MODULE_LICENSE("GPL");
+
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