[ARM] 3405/1: lpd7a40x: CPLD ssp driver

Patch from Marc Singer

Driver for operating SSP devices through LPD7A40X CPLD chip.  This
driver is used by the audio codecs.

Signed-off-by: Marc Singer <elf@buici.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 348 insertions, 0 deletions

diff --git a/arch/arm/mach-lh7a40x/Kconfig b/arch/arm/mach-lh7a40x/Kconfig
index 8a17867a6a24..558a34f53b1c 100644
--- a/arch/arm/mach-lh7a40x/Kconfig
+++ b/arch/arm/mach-lh7a40x/Kconfig
@@ -14,6 +14,7 @@ config MACH_LPD7A400
         bool "LPD7A400 Card Engine"
         select ARCH_LH7A400
 #       select IDE_POLL
+        select HAS_TOUCHSCREEN_ADS7843_LH7
         help
           Say Y here if you are using Logic Product Development's
           LPD7A400 CardEngine.  For the time being, the LPD7A400 and
@@ -23,6 +24,7 @@ config MACH_LPD7A404
         bool "LPD7A404 Card Engine"
         select ARCH_LH7A404
 #       select IDE_POLL
+        select HAS_TOUCHSCREEN_ADC_LH7
         help
           Say Y here if you are using Logic Product Development's
           LPD7A404 CardEngine. For the time being, the LPD7A400 and
@@ -34,6 +36,9 @@ config ARCH_LH7A400
 config ARCH_LH7A404
         bool
 
+config LPD7A40X_CPLD_SSP
+        bool
+
 config LH7A40X_CONTIGMEM
         bool "Disable NUMA Support"
         depends on ARCH_LH7A40X
diff --git a/arch/arm/mach-lh7a40x/ssp-cpld.c b/arch/arm/mach-lh7a40x/ssp-cpld.c
new file mode 100644
index 000000000000..a10830186dac
--- /dev/null
+++ b/arch/arm/mach-lh7a40x/ssp-cpld.c
@@ -0,0 +1,343 @@
+/* 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");