[patch 18/19] chardev: pc8736x_gpio - finish shadow-current for pc87360x_gpio

GPIO SUPPORT FOR SCx200 & PC8736x

This patch-set reworks the 2.4 vintage scx200_gpio driver for modern
2.6, and refactors GPIO support to reuse it in a new driver for the
GPIO on PC-8736x chips.

18/19. patch.shadow-current

pc8736x_gpio needs a real nsc_gpio_ops.gpio_current(), (the previous
just threw a dev_warn).  This patch adds that code to read the chip's
current-pin-output-settings, then adds the initialization of the
shadow-regs to them.  (the shadow regs are there to preclude the slow
peripheral access needed otherwize)

Signed-off-by:  Jim Cromie <jim.cromie@xxxxxxxxx>

diffstat patch.shadow-current
pc8736x_gpio.c |   29 ++++++++++++++++++++++++-----
1 files changed, 24 insertions(+), 5 deletions(-)


diff -ruNp -X dontdiff -X exclude-diffs k16r-18/drivers/char/pc8736x_gpio.c 
k16r-19/drivers/char/pc8736x_gpio.c
--- k16r-18/drivers/char/pc8736x_gpio.c 2006-05-28 12:23:25.000000000 -0600
+++ k16r-19/drivers/char/pc8736x_gpio.c 2006-05-28 12:23:58.000000000 -0600
@@ -33,7 +33,7 @@ MODULE_PARM_DESC(major, "Major device nu

static DEFINE_SPINLOCK(pc8736x_gpio_config_lock);
static unsigned pc8736x_gpio_base;
-/* static u8 pc8736x_gpio_shadow[4]; */
+static u8 pc8736x_gpio_shadow[4];

#define SIO_BASE1       0x2E    /* 1st command-reg to check */
#define SIO_BASE2       0x4E    /* alt command-reg to check */
@@ -191,6 +191,7 @@ static void pc8736x_gpio_set(unsigned mi
        val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);

        dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val);
+       pc8736x_gpio_shadow[port] = val;
}

static void pc8736x_gpio_set_high(unsigned index)
@@ -203,15 +204,18 @@ static void pc8736x_gpio_set_low(unsigne
        pc8736x_gpio_set(index, 0);
}

-static int pc8736x_gpio_current(unsigned index)
+static int pc8736x_gpio_current(unsigned minor)
{
-       dev_warn(&pdev->dev, "pc8736x_gpio_current unimplemented\n");
-       return 0;
+       int port, bit;
+       minor &= 0x1f;
+       port = minor >> 3;
+       bit = minor & 7;
+       return pc8736x_gpio_shadow[port] >> bit & 0x01;
}

static void pc8736x_gpio_change(unsigned index)
{
-       pc8736x_gpio_set(index, !pc8736x_gpio_get(index));
+       pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
}

extern void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned iminor);
@@ -247,6 +251,18 @@ static struct file_operations pc8736x_gp
        .read   = nsc_gpio_read,
};

+static void __init pc8736x_init_shadow(void)
+{
+       int port;
+
+       /* read the current values driven on the GPIO signals */
+       for (port = 0; port < 4; ++port)
+               pc8736x_gpio_shadow[port]
+                   = inb_p(pc8736x_gpio_base + port_offset[port]
+                           + PORT_OUT);
+
+}
+
static int __init pc8736x_gpio_init(void)
{
        int r, rc;
@@ -292,6 +308,7 @@ static int __init pc8736x_gpio_init(void
                dev_info(&pdev->dev, "GPIO ioport %x reserved\n",
                         pc8736x_gpio_base);

+       pc8736x_init_shadow();

        r = register_chrdev(major, DEVNAME, &pc8736x_gpio_fops);
        if (r < 0) {
@@ -315,5 +332,7 @@ static void __exit pc8736x_gpio_cleanup(
        unregister_chrdev(major, DEVNAME);
}

+EXPORT_SYMBOL(pc8736x_access);
+
module_init(pc8736x_gpio_init);
module_exit(pc8736x_gpio_cleanup);