MIPS: RB532: Provide functions for gpio configuration

As gpiolib doesn't support pin multiplexing, it provides no way to
access the GPIOFUNC register. Also there is no support for setting
interrupt status and level. These functions provide access to them and
are needed by the CompactFlash driver.
Signed-off-by: NPhil Sutter <n0-1@freewrt.org>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-rc32434/gpio.h

@@ -84,5 +84,7 @@ extern void set_434_reg(unsigned reg_offs, unsigned bit, unsigned len, unsigned
 extern unsigned get_434_reg(unsigned reg_offs);
 extern void set_latch_u5(unsigned char or_mask, unsigned char nand_mask);
 extern unsigned char get_latch_u5(void);
+extern void rb532_gpio_set_ilevel(int bit, unsigned gpio);
+extern void rb532_gpio_set_istat(int bit, unsigned gpio);
 
 #endif /* _RC32434_GPIO_H_ */

arch/mips/rb532/gpio.c

@@ -39,10 +39,6 @@
 struct rb532_gpio_chip {
 	struct gpio_chip chip;
 	void __iomem	 *regbase;
-	void		(*set_int_level)(struct gpio_chip *chip, unsigned offset, int value);
-	int		(*get_int_level)(struct gpio_chip *chip, unsigned offset);
-	void		(*set_int_status)(struct gpio_chip *chip, unsigned offset, int value);
-	int		(*get_int_status)(struct gpio_chip *chip, unsigned offset);
 };
 
 struct mpmc_device dev3;
@@ -111,162 +107,95 @@ unsigned char get_latch_u5(void)
 }
 EXPORT_SYMBOL(get_latch_u5);
 
-/*
- * Return GPIO level */
-static int rb532_gpio_get(struct gpio_chip *chip, unsigned offset)
-{
-	u32			mask = 1 << offset;
-	struct rb532_gpio_chip	*gpch;
-
-	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	return readl(gpch->regbase + GPIOD) & mask;
-}
-
-/*
- * Set output GPIO level
+/* rb532_set_bit - sanely set a bit
+ *
+ * bitval: new value for the bit
+ * offset: bit index in the 4 byte address range
+ * ioaddr: 4 byte aligned address being altered
  */
-static void rb532_gpio_set(struct gpio_chip *chip,
-				unsigned offset, int value)
+static inline void rb532_set_bit(unsigned bitval,
+		unsigned offset, void __iomem *ioaddr)
 {
 	unsigned long flags;
-	u32			mask = 1 << offset;
-	u32			tmp;
-	struct rb532_gpio_chip	*gpch;
-	void __iomem		*gpvr;
+	u32 val;
 
-	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	gpvr = gpch->regbase + GPIOD;
+	bitval = !!bitval;              /* map parameter to {0,1} */
 
 	local_irq_save(flags);
-	tmp = readl(gpvr);
-	if (value)
-		tmp |= mask;
-	else
-		tmp &= ~mask;
-	writel(tmp, gpvr);
+
+	val = readl(ioaddr);
+	val &= ~( ~bitval << offset );   /* unset bit if bitval == 0 */
+	val |=  (  bitval << offset );   /* set bit if bitval == 1 */
+	writel(val, ioaddr);
+
 	local_irq_restore(flags);
 }
 
-/*
- * Set GPIO direction to input
+/* rb532_get_bit - read a bit
+ *
+ * returns the boolean state of the bit, which may be > 1
  */
-static int rb532_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+static inline int rb532_get_bit(unsigned offset, void __iomem *ioaddr)
 {
-	unsigned long		flags;
-	u32			mask = 1 << offset;
-	u32			value;
-	struct rb532_gpio_chip	*gpch;
-	void __iomem		*gpdr;
-
-	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	gpdr = gpch->regbase + GPIOCFG;
-
-	local_irq_save(flags);
-	value = readl(gpdr);
-	value &= ~mask;
-	writel(value, gpdr);
-	local_irq_restore(flags);
-
-	return 0;
+	return (readl(ioaddr) & (1 << offset));
 }
 
 /*
- * Set GPIO direction to output
- */
-static int rb532_gpio_direction_output(struct gpio_chip *chip,
-					unsigned offset, int value)
+ * Return GPIO level */
+static int rb532_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
-	unsigned long		flags;
-	u32			mask = 1 << offset;
-	u32			tmp;
 	struct rb532_gpio_chip	*gpch;
-	void __iomem		*gpdr;
 
 	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	writel(mask, gpch->regbase + GPIOD);
-	gpdr = gpch->regbase + GPIOCFG;
-
-	local_irq_save(flags);
-	tmp = readl(gpdr);
-	tmp |= mask;
-	writel(tmp, gpdr);
-	local_irq_restore(flags);
-
-	return 0;
+	return rb532_get_bit(offset, gpch->regbase + GPIOD);
 }
 
 /*
- * Set the GPIO interrupt level
+ * Set output GPIO level
  */
-static void rb532_gpio_set_int_level(struct gpio_chip *chip,
+static void rb532_gpio_set(struct gpio_chip *chip,
 				unsigned offset, int value)
 {
-	unsigned long		flags;
-	u32			mask = 1 << offset;
-	u32			tmp;
 	struct rb532_gpio_chip	*gpch;
-	void __iomem		*gpil;
 
 	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	gpil = gpch->regbase + GPIOILEVEL;
-
-	local_irq_save(flags);
-	tmp = readl(gpil);
-	if (value)
-		tmp |= mask;
-	else
-		tmp &= ~mask;
-	writel(tmp, gpil);
-	local_irq_restore(flags);
+	rb532_set_bit(value, offset, gpch->regbase + GPIOD);
 }
 
 /*
- * Get the GPIO interrupt level
+ * Set GPIO direction to input
  */
-static int rb532_gpio_get_int_level(struct gpio_chip *chip, unsigned offset)
+static int rb532_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 {
-	u32			mask = 1 << offset;
 	struct rb532_gpio_chip	*gpch;
 
 	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	return readl(gpch->regbase + GPIOILEVEL) & mask;
+
+	if (rb532_get_bit(offset, gpch->regbase + GPIOFUNC))
+		return 1;	/* alternate function, GPIOCFG is ignored */
+
+	rb532_set_bit(0, offset, gpch->regbase + GPIOCFG);
+	return 0;
 }
 
 /*
- * Set the GPIO interrupt status
+ * Set GPIO direction to output
  */
-static void rb532_gpio_set_int_status(struct gpio_chip *chip,
+static int rb532_gpio_direction_output(struct gpio_chip *chip,
 					unsigned offset, int value)
 {
-	unsigned long		flags;
-	u32			mask = 1 << offset;
-	u32			tmp;
 	struct rb532_gpio_chip	*gpch;
-	void __iomem		*gpis;
 
 	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	gpis = gpch->regbase + GPIOISTAT;
 
-	local_irq_save(flags);
-	tmp = readl(gpis);
-	if (value)
-		tmp |= mask;
-	else
-		tmp &= ~mask;
-	writel(tmp, gpis);
-	local_irq_restore(flags);
-}
+	if (rb532_get_bit(offset, gpch->regbase + GPIOFUNC))
+		return 1;	/* alternate function, GPIOCFG is ignored */
 
-/*
- * Get the GPIO interrupt status
- */
-static int rb532_gpio_get_int_status(struct gpio_chip *chip, unsigned offset)
-{
-	u32			mask = 1 << offset;
-	struct rb532_gpio_chip	*gpch;
+	/* set the initial output value */
+	rb532_set_bit(value, offset, gpch->regbase + GPIOD);
 
-	gpch = container_of(chip, struct rb532_gpio_chip, chip);
-	return readl(gpch->regbase + GPIOISTAT) & mask;
+	rb532_set_bit(1, offset, gpch->regbase + GPIOCFG);
+	return 0;
 }
 
 static struct rb532_gpio_chip rb532_gpio_chip[] = {
@@ -280,13 +209,35 @@ static struct rb532_gpio_chip rb532_gpio_chip[] = {
 			.base			= 0,
 			.ngpio			= 32,
 		},
-		.get_int_level		= rb532_gpio_get_int_level,
-		.set_int_level		= rb532_gpio_set_int_level,
-		.get_int_status		= rb532_gpio_get_int_status,
-		.set_int_status		= rb532_gpio_set_int_status,
 	},
 };
 
+/*
+ * Set GPIO interrupt level
+ */
+void rb532_gpio_set_ilevel(int bit, unsigned gpio)
+{
+	rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOILEVEL);
+}
+EXPORT_SYMBOL(rb532_gpio_set_ilevel);
+
+/*
+ * Set GPIO interrupt status
+ */
+void rb532_gpio_set_istat(int bit, unsigned gpio)
+{
+	rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOISTAT);
+}
+EXPORT_SYMBOL(rb532_gpio_set_istat);
+
+/*
+ * Configure GPIO alternate function
+ */
+static void rb532_gpio_set_func(int bit, unsigned gpio)
+{
+       rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOFUNC);
+}
+
 int __init rb532_gpio_init(void)
 {
 	struct resource *r;
@@ -310,9 +261,11 @@ int __init rb532_gpio_init(void)
 		return -ENXIO;
 	}
 
-	/* Set the interrupt status and level for the CF pin */
-	rb532_gpio_set_int_level(&rb532_gpio_chip->chip, CF_GPIO_NUM, 1);
-	rb532_gpio_set_int_status(&rb532_gpio_chip->chip, CF_GPIO_NUM, 0);
+	/* configure CF_GPIO_NUM as CFRDY IRQ source */
+	rb532_gpio_set_func(0, CF_GPIO_NUM);
+	rb532_gpio_direction_input(&rb532_gpio_chip->chip, CF_GPIO_NUM);
+	rb532_gpio_set_ilevel(1, CF_GPIO_NUM);
+	rb532_gpio_set_istat(0, CF_GPIO_NUM);
 
 	return 0;
 }