[PATCH v5 07/15] ARM: mxs: Add gpio support

Hello Shawn,

On Fri, Dec 10, 2010 at 04:06:40PM +0800, Shawn Guo wrote:

+	/* set level or edge */
+	if (edge & GPIO_INT_LEV_MASK)
+		__raw_writel(1 << (gpio & 31),
+			port->base + PINCTRL_IRQLEV(port->id) + MXS_SET_ADDR);
+	else
+		__raw_writel(1 << (gpio & 31),
+			port->base + PINCTRL_IRQLEV(port->id) + MXS_CLR_ADDR);

Is this preferable?:

	__raw_writel(1 << (gpio & 31), port->base + PINCTRL_IRQLEV(port->id) +
		(edge & GPIO_INT_LEV_MASK ? MXS_SET_ADDR : MXS_CLR_ADDR))

.  I'm not sure.  And if you like my __raw_setl/__raw_clearl (or
__raw_clrl?) suggestion this won't work though.  If you don't, I'd
prefer to be easily able to see that the two commands only differ by
MXS_SET_ADDR vs. MXS_CLR_ADDR.

e.g.

	u32 nicename = 1 << (gpio & 31);
	correcttype addr = port->base + PINCTRL_IRQLEV(port->id);

	if (edge & GPIO_INT_LEV_MASK)
		__raw_writel(nicename, addr + MXS_SET_ADDR);
	else
		__raw_writel(nicename, addr + MXS_CLR_ADDR);

+	/* set polarity */
+	if (edge & GPIO_INT_POL_MASK)
+		__raw_writel(1 << (gpio & 31),
+			port->base + PINCTRL_IRQPOL(port->id) + MXS_SET_ADDR);
+	else
+		__raw_writel(1 << (gpio & 31),
+			port->base + PINCTRL_IRQPOL(port->id) + MXS_CLR_ADDR);

ditto.  You can even reuse nicename here.

+
+	_clear_gpio_irqstatus(port, gpio & 0x1f);
+
+	return 0;
+}
+
+/* MXS has one interrupt *per* gpio port */
+static void mxs_gpio_irq_handler(u32 irq, struct irq_desc *desc)
+{
+	u32 irq_stat;
+	struct mxs_gpio_port *port = (struct mxs_gpio_port *)get_irq_data(irq);
+	u32 gpio_irq_no_base = port->virtual_irq_start;
+
+	irq_stat = __raw_readl(port->base + PINCTRL_IRQSTAT(port->id)) &
+			__raw_readl(port->base + PINCTRL_IRQEN(port->id)) &
+			__raw_readl(port->base + PINCTRL_PIN2IRQ(port->id));

I think now a bit set in PINCTRL_IRQEN implies the same bit set in
PINCTRL_PIN2IRQ, doesn't it?  If so, & PINCTRL_PIN2IRQ doesn't add any
value.

+static void _set_gpio_direction(struct gpio_chip *chip, unsigned offset,
+				int dir)

mxs_gpio_direction_set would better match the naming scheme of
mxs_gpio_direction_input and mxs_gpio_direction_output.  (If you ask me,
don't use leading underscores in .c files, static is enough to signal
the function to be private.)

+{
+	struct mxs_gpio_port *port =
+		container_of(chip, struct mxs_gpio_port, chip);
+
+	if (dir)
+		__raw_writel(1 << offset,
+			port->base + PINCTRL_DOE(port->id) + MXS_SET_ADDR);
+	else
+		__raw_writel(1 << offset,
+			port->base + PINCTRL_DOE(port->id) + MXS_CLR_ADDR);

as above, at least give a name for port->base + PINCTRL_DOE(port->id).

+int __init mxs_gpio_init(struct mxs_gpio_port *port, int cnt)
+{
+	int i, j;
+
+	/* save for local usage */
+	mxs_gpio_ports = port;
+	gpio_table_size = cnt;
+
+	pr_info("MXS GPIO hardware\n");
+
+	for (i = 0; i < cnt; i++) {
+		/* disable the interrupt and clear the status */
+		__raw_writel(0, port[i].base +
+				PINCTRL_PIN2IRQ(i));
+		__raw_writel(0, port[i].base +
+				PINCTRL_IRQEN(i));
+		__raw_writel(~0, port[i].base +
+				PINCTRL_IRQSTAT(i) + MXS_CLR_ADDR);

Why not __raw_writel(0, port[i].base + PINCTRL_IRQSTAT(i)) ?
(And note that applying ~ on a signed integer isn't portable in
general.  For all sane archs this is the same as ~0U though and ARM is
sane (here), still I think it's good to be aware of such things and
avoid them if easily possible.)

+		/* its a serious configuration bug when it fails */
+		BUG_ON( gpiochip_add(&port[i].chip) < 0 );
+
+		/* setup one handler for each entry */
+		set_irq_chained_handler(port[i].irq, mxs_gpio_irq_handler);
+		set_irq_data(port[i].irq, &port[i]);

I think it's saver to first setup the irq stuff and only then register
the gpiochip.

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-K?nig            |
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