[patch 17/20] chardev: GPIO for PC8736x: add proper shadow-regs for pc8736x_gpio

[Jim Cromie <jim.cromie@xxxxxxxxx>]

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 ab-16/drivers/char/pc8736x_gpio.c ab-17/drivers/char/pc8736x_gpio.c
--- ab-16/drivers/char/pc8736x_gpio.c	2006-06-02 13:39:15.000000000 -0600
+++ ab-17/drivers/char/pc8736x_gpio.c	2006-06-02 13:40:23.000000000 -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);



--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/