MIPS: Alchemy: support multiple GPIO styles in one kernel

For GPIOLIB=y decide at runtime which gpiochips to register;
in the GPIOLIB=n case, the gpio headers need to be reshuffled
a bit to make multiple implementations coexist peacefully.

Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
To: Linux-MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2679/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 78 insertions, 32 deletions

diff --git a/arch/mips/include/asm/mach-au1x00/gpio-au1000.h b/arch/mips/include/asm/mach-au1x00/gpio-au1000.h
index 1f41a522906d..73853b5a2a31 100644
--- a/arch/mips/include/asm/mach-au1x00/gpio-au1000.h
+++ b/arch/mips/include/asm/mach-au1x00/gpio-au1000.h
@@ -347,17 +347,6 @@ static inline int alchemy_gpio2_to_irq(int gpio)
 
 /**********************************************************************/
 
-/* On Au1000, Au1500 and Au1100 GPIOs won't work as inputs before
- * SYS_PININPUTEN is written to at least once.  On Au1550/Au1200 this
- * register enables use of GPIOs as wake source.
- */
-static inline void alchemy_gpio1_input_enable(void)
-{
-	void __iomem *base = (void __iomem *)KSEG1ADDR(AU1000_SYS_PHYS_ADDR);
-	__raw_writel(0, base + SYS_PININPUTEN);	/* the write op is key */
-	wmb();
-}
-
 /* GPIO2 shared interrupts and control */
 
 static inline void __alchemy_gpio2_mod_int(int gpio2, int en)
@@ -561,6 +550,7 @@ static inline int alchemy_irq_to_gpio(int irq)
 
 #ifndef CONFIG_GPIOLIB
 
+#ifdef CONFIG_ALCHEMY_GPIOINT_AU1000
 
 #ifndef CONFIG_ALCHEMY_GPIO_INDIRECT	/* case (4) */
 
@@ -665,24 +655,7 @@ static inline void gpio_unexport(unsigned gpio)
 
 #endif	/* !CONFIG_ALCHEMY_GPIO_INDIRECT */
 
-
-#else	/* CONFIG GPIOLIB */
-
-
- /* using gpiolib to provide up to 2 gpio_chips for on-chip gpios */
-#ifndef CONFIG_ALCHEMY_GPIO_INDIRECT	/* case (2) */
-
-/* get everything through gpiolib */
-#define gpio_to_irq	__gpio_to_irq
-#define gpio_get_value	__gpio_get_value
-#define gpio_set_value	__gpio_set_value
-#define gpio_cansleep	__gpio_cansleep
-#define irq_to_gpio	alchemy_irq_to_gpio
-
-#include <asm-generic/gpio.h>
-
-#endif	/* !CONFIG_ALCHEMY_GPIO_INDIRECT */
-
+#endif	/* CONFIG_ALCHEMY_GPIOINT_AU1000 */
 
 #endif	/* !CONFIG_GPIOLIB */
 
diff --git a/arch/mips/include/asm/mach-au1x00/gpio.h b/arch/mips/include/asm/mach-au1x00/gpio.h
index c3f60cdc3203..fcdc8c4809db 100644
--- a/arch/mips/include/asm/mach-au1x00/gpio.h
+++ b/arch/mips/include/asm/mach-au1x00/gpio.h
@@ -1,10 +1,83 @@
+/*
+ * Alchemy GPIO support.
+ *
+ * With CONFIG_GPIOLIB=y different types of on-chip GPIO can be supported within
+ *  the same kernel image.
+ * With CONFIG_GPIOLIB=n, your board must select ALCHEMY_GPIOINT_AU1XXX for the
+ *  appropriate CPU type (AU1000 currently).
+ */
+
 #ifndef _ALCHEMY_GPIO_H_
 #define _ALCHEMY_GPIO_H_
 
-#if defined(CONFIG_ALCHEMY_GPIOINT_AU1000)
-
+#include <asm/mach-au1x00/au1000.h>
 #include <asm/mach-au1x00/gpio-au1000.h>
 
-#endif
+/* On Au1000, Au1500 and Au1100 GPIOs won't work as inputs before
+ * SYS_PININPUTEN is written to at least once.  On Au1550/Au1200/Au1300 this
+ * register enables use of GPIOs as wake source.
+ */
+static inline void alchemy_gpio1_input_enable(void)
+{
+	void __iomem *base = (void __iomem *)KSEG1ADDR(AU1000_SYS_PHYS_ADDR);
+	__raw_writel(0, base + 0x110);		/* the write op is key */
+	wmb();
+}
+
+
+/* Linux gpio framework integration.
+*
+* 4 use cases of Alchemy GPIOS:
+*(1) GPIOLIB=y, ALCHEMY_GPIO_INDIRECT=y:
+*	Board must register gpiochips.
+*(2) GPIOLIB=y, ALCHEMY_GPIO_INDIRECT=n:
+*	A gpiochip for the 75 GPIOs is registered.
+*
+*(3) GPIOLIB=n, ALCHEMY_GPIO_INDIRECT=y:
+*	the boards' gpio.h must provide	the linux gpio wrapper functions,
+*
+*(4) GPIOLIB=n, ALCHEMY_GPIO_INDIRECT=n:
+*	inlinable gpio functions are provided which enable access to the
+*	Au1300 gpios only by using the numbers straight out of the data-
+*	sheets.
+
+* Cases 1 and 3 are intended for boards which want to provide their own
+* GPIO namespace and -operations (i.e. for example you have 8 GPIOs
+* which are in part provided by spare Au1300 GPIO pins and in part by
+* an external FPGA but you still want them to be accssible in linux
+* as gpio0-7. The board can of course use the alchemy_gpioX_* functions
+* as required).
+*/
+
+#ifdef CONFIG_GPIOLIB
+
+/* wraps the cpu-dependent irq_to_gpio functions */
+/* FIXME: gpiolib needs an irq_to_gpio hook */
+static inline int __au_irq_to_gpio(unsigned int irq)
+{
+	switch (alchemy_get_cputype()) {
+	case ALCHEMY_CPU_AU1000...ALCHEMY_CPU_AU1200:
+		return alchemy_irq_to_gpio(irq);
+	}
+	return -EINVAL;
+}
+
+
+/* using gpiolib to provide up to 2 gpio_chips for on-chip gpios */
+#ifndef CONFIG_ALCHEMY_GPIO_INDIRECT	/* case (2) */
+
+/* get everything through gpiolib */
+#define gpio_to_irq	__gpio_to_irq
+#define gpio_get_value	__gpio_get_value
+#define gpio_set_value	__gpio_set_value
+#define gpio_cansleep	__gpio_cansleep
+#define irq_to_gpio	__au_irq_to_gpio
+
+#include <asm-generic/gpio.h>
+
+#endif	/* !CONFIG_ALCHEMY_GPIO_INDIRECT */
+
+
+#endif	/* CONFIG_GPIOLIB */
 
 #endif	/* _ALCHEMY_GPIO_H_ */