--- /dev/null
+/* arch/arm/mach-lh7a40x/ssp-cpld.c
+ *
+ * Copyright (C) 2004,2005 Marc Singer
+ *
+ * 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/SPI driver for the CardEngine CPLD.
+ *
+ */
+
+/* NOTES
+ -----
+
+ o *** This driver is cribbed from the 7952x implementation.
+ Some comments may not apply.
+
+ o This driver contains sufficient logic to control either the
+ serial EEPROMs or the audio codec. It is included in the kernel
+ to support the codec. The EEPROMs are really the responsibility
+ of the boot loader and should probably be left alone.
+
+ o The code must be augmented to cope with multiple, simultaneous
+ clients.
+ o The audio codec writes to the codec chip whenever playback
+ starts.
+ o The touchscreen driver writes to the ads chip every time it
+ samples.
+ o The audio codec must write 16 bits, but the touch chip writes
+ are 8 bits long.
+ o We need to be able to keep these configurations separate while
+ simultaneously active.
+
+ */
+
+#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/delay.h>
+#include <linux/spinlock.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/hardware.h>
+
+#include <asm/arch/ssp.h>
+
+//#define TALK
+
+#if defined (TALK)
+#define PRINTK(f...) printk (f)
+#else
+#define PRINTK(f...) do {} while (0)
+#endif
+
+#if defined (CONFIG_ARCH_LH7A400)
+# define CPLD_SPID __REGP16(CPLD06_VIRT) /* SPI data */
+# define CPLD_SPIC __REGP16(CPLD08_VIRT) /* SPI control */
+# define CPLD_SPIC_CS_CODEC (1<<0)
+# define CPLD_SPIC_CS_TOUCH (1<<1)
+# define CPLD_SPIC_WRITE (0<<2)
+# define CPLD_SPIC_READ (1<<2)
+# define CPLD_SPIC_DONE (1<<3) /* r/o */
+# define CPLD_SPIC_LOAD (1<<4)
+# define CPLD_SPIC_START (1<<4)
+# define CPLD_SPIC_LOADED (1<<5) /* r/o */
+#endif
+
+#define CPLD_SPI __REGP16(CPLD0A_VIRT) /* SPI operation */
+#define CPLD_SPI_CS_EEPROM (1<<3)
+#define CPLD_SPI_SCLK (1<<2)
+#define CPLD_SPI_TX_SHIFT (1)
+#define CPLD_SPI_TX (1<<CPLD_SPI_TX_SHIFT)
+#define CPLD_SPI_RX_SHIFT (0)
+#define CPLD_SPI_RX (1<<CPLD_SPI_RX_SHIFT)
+
+/* *** FIXME: these timing values are substantially larger than the
+ *** chip requires. We may implement an nsleep () function. */
+#define T_SKH 1 /* Clock time high (us) */
+#define T_SKL 1 /* Clock time low (us) */
+#define T_CS 1 /* Minimum chip select low time (us) */
+#define T_CSS 1 /* Minimum chip select setup time (us) */
+#define T_DIS 1 /* Data setup time (us) */
+
+ /* EEPROM SPI bits */
+#define P_START (1<<9)
+#define P_WRITE (1<<7)
+#define P_READ (2<<7)
+#define P_ERASE (3<<7)
+#define P_EWDS (0<<7)
+#define P_WRAL (0<<7)
+#define P_ERAL (0<<7)
+#define P_EWEN (0<<7)
+#define P_A_EWDS (0<<5)
+#define P_A_WRAL (1<<5)
+#define P_A_ERAL (2<<5)
+#define P_A_EWEN (3<<5)
+
+struct ssp_configuration {
+ int device;
+ int mode;
+ int speed;
+ int frame_size_write;
+ int frame_size_read;
+};
+
+static struct ssp_configuration ssp_configuration;
+static spinlock_t ssp_lock;
+
+static void enable_cs (void)
+{
+ switch (ssp_configuration.device) {
+ case DEVICE_EEPROM:
+ CPLD_SPI |= CPLD_SPI_CS_EEPROM;
+ break;
+ }
+ udelay (T_CSS);
+}
+
+static void disable_cs (void)
+{
+ switch (ssp_configuration.device) {
+ case DEVICE_EEPROM:
+ CPLD_SPI &= ~CPLD_SPI_CS_EEPROM;
+ break;
+ }
+ udelay (T_CS);
+}
+
+static void pulse_clock (void)
+{
+ CPLD_SPI |= CPLD_SPI_SCLK;
+ udelay (T_SKH);
+ CPLD_SPI &= ~CPLD_SPI_SCLK;
+ udelay (T_SKL);
+}
+
+
+/* execute_spi_command
+
+ sends an spi command to a device. It first sends cwrite bits from
+ v. If cread is greater than zero it will read cread bits
+ (discarding the leading 0 bit) and return them. If cread is less
+ than zero it will check for completetion status and return 0 on
+ success or -1 on timeout. If cread is zero it does nothing other
+ than sending the command.
+
+ On the LPD7A400, we can only read or write multiples of 8 bits on
+ the codec and the touch screen device. Here, we round up.
+
+*/
+
+static int execute_spi_command (int v, int cwrite, int cread)
+{
+ unsigned long l = 0;
+
+#if defined (CONFIG_MACH_LPD7A400)
+ /* The codec and touch devices cannot be bit-banged. Instead,
+ * the CPLD provides an eight-bit shift register and a crude
+ * interface. */
+ if ( ssp_configuration.device == DEVICE_CODEC
+ || ssp_configuration.device == DEVICE_TOUCH) {
+ int select = 0;
+
+ PRINTK ("spi(%d %d.%d) 0x%04x",
+ ssp_configuration.device, cwrite, cread,
+ v);
+#if defined (TALK)
+ if (ssp_configuration.device == DEVICE_CODEC)
+ PRINTK (" 0x%03x -> %2d", v & 0x1ff, (v >> 9) & 0x7f);
+#endif
+ PRINTK ("\n");
+
+ if (ssp_configuration.device == DEVICE_CODEC)
+ select = CPLD_SPIC_CS_CODEC;
+ if (ssp_configuration.device == DEVICE_TOUCH)
+ select = CPLD_SPIC_CS_TOUCH;
+ if (cwrite) {
+ for (cwrite = (cwrite + 7)/8; cwrite-- > 0; ) {
+ CPLD_SPID = (v >> (8*cwrite)) & 0xff;
+ CPLD_SPIC = select | CPLD_SPIC_LOAD;
+ while (!(CPLD_SPIC & CPLD_SPIC_LOADED))
+ ;
+ CPLD_SPIC = select;
+ while (!(CPLD_SPIC & CPLD_SPIC_DONE))
+ ;
+ }
+ v = 0;
+ }
+ if (cread) {
+ mdelay (2); /* *** FIXME: required by ads7843? */
+ v = 0;
+ for (cread = (cread + 7)/8; cread-- > 0;) {
+ CPLD_SPID = 0;
+ CPLD_SPIC = select | CPLD_SPIC_READ
+ | CPLD_SPIC_START;
+ while (!(CPLD_SPIC & CPLD_SPIC_LOADED))
+ ;
+ CPLD_SPIC = select | CPLD_SPIC_READ;
+ while (!(CPLD_SPIC & CPLD_SPIC_DONE))
+ ;
+ v = (v << 8) | CPLD_SPID;
+ }
+ }
+ return v;
+ }
+#endif
+
+ PRINTK ("spi(%d) 0x%04x -> 0x%x\r\n", ssp_configuration.device,
+ v & 0x1ff, (v >> 9) & 0x7f);
+
+ enable_cs ();
+
+ v <<= CPLD_SPI_TX_SHIFT; /* Correction for position of SPI_TX bit */
+ while (cwrite--) {
+ CPLD_SPI
+ = (CPLD_SPI & ~CPLD_SPI_TX)
+ | ((v >> cwrite) & CPLD_SPI_TX);
+ udelay (T_DIS);
+ pulse_clock ();
+ }
+
+ if (cread < 0) {
+ int delay = 10;
+ disable_cs ();
+ udelay (1);
+ enable_cs ();
+
+ l = -1;
+ do {
+ if (CPLD_SPI & CPLD_SPI_RX) {
+ l = 0;
+ break;
+ }
+ } while (udelay (1), --delay);
+ }
+ else
+ /* We pulse the clock before the data to skip the leading zero. */
+ while (cread-- > 0) {
+ pulse_clock ();
+ l = (l<<1)
+ | (((CPLD_SPI & CPLD_SPI_RX)
+ >> CPLD_SPI_RX_SHIFT) & 0x1);
+ }
+
+ disable_cs ();
+ return l;
+}
+
+static int ssp_init (void)
+{
+ spin_lock_init (&ssp_lock);
+ memset (&ssp_configuration, 0, sizeof (ssp_configuration));
+ return 0;
+}
+
+
+/* ssp_chip_select
+
+ drops the chip select line for the CPLD shift-register controlled
+ devices. It doesn't enable chip
+
+*/
+
+static void ssp_chip_select (int enable)
+{
+#if defined (CONFIG_MACH_LPD7A400)
+ int select;
+
+ if (ssp_configuration.device == DEVICE_CODEC)
+ select = CPLD_SPIC_CS_CODEC;
+ else if (ssp_configuration.device == DEVICE_TOUCH)
+ select = CPLD_SPIC_CS_TOUCH;
+ else
+ return;
+
+ if (enable)
+ CPLD_SPIC = select;
+ else
+ CPLD_SPIC = 0;
+#endif
+}
+
+static void ssp_acquire (void)
+{
+ spin_lock (&ssp_lock);
+}
+
+static void ssp_release (void)
+{
+ ssp_chip_select (0); /* just in case */
+ spin_unlock (&ssp_lock);
+}
+
+static int ssp_configure (int device, int mode, int speed,
+ int frame_size_write, int frame_size_read)
+{
+ ssp_configuration.device = device;
+ ssp_configuration.mode = mode;
+ ssp_configuration.speed = speed;
+ ssp_configuration.frame_size_write = frame_size_write;
+ ssp_configuration.frame_size_read = frame_size_read;
+
+ return 0;
+}
+
+static int ssp_read (void)
+{
+ return execute_spi_command (0, 0, ssp_configuration.frame_size_read);
+}
+
+static int ssp_write (u16 data)
+{
+ execute_spi_command (data, ssp_configuration.frame_size_write, 0);
+ return 0;
+}
+
+static int ssp_write_read (u16 data)
+{
+ return execute_spi_command (data, ssp_configuration.frame_size_write,
+ ssp_configuration.frame_size_read);
+}
+
+struct ssp_driver lh7a40x_cpld_ssp_driver = {
+ .init = ssp_init,
+ .acquire = ssp_acquire,
+ .release = ssp_release,
+ .configure = ssp_configure,
+ .chip_select = ssp_chip_select,
+ .read = ssp_read,
+ .write = ssp_write,
+ .write_read = ssp_write_read,
+};
+
+
+MODULE_AUTHOR("Marc Singer");
+MODULE_DESCRIPTION("LPD7A40X CPLD SPI driver");
+MODULE_LICENSE("GPL");
projects / linux-2.6 / commitdiff