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>

arch/mips/alchemy/common/Makefile

@@ -12,9 +12,7 @@ obj-$(CONFIG_ALCHEMY_GPIOINT_AU1000) += irq.o
 
 # optional gpiolib support
 ifeq ($(CONFIG_ALCHEMY_GPIO_INDIRECT),)
- ifeq ($(CONFIG_GPIOLIB),y)
-  obj-$(CONFIG_ALCHEMY_GPIOINT_AU1000) += gpiolib-au1000.o
- endif
+ obj-$(CONFIG_GPIOLIB) += gpiolib.o
 endif
 
 obj-$(CONFIG_PCI)		+= pci.o

arch/mips/alchemy/common/gpiolib-au1000.c → arch/mips/alchemy/common/gpiolib.c

 /*
  *  Copyright (C) 2007-2009, OpenWrt.org, Florian Fainelli <florian@openwrt.org>
- *  	GPIOLIB support for Au1000, Au1500, Au1100, Au1550 and Au12x0.
+ *	GPIOLIB support for Alchemy chips.
  *
  *  This program is free software; you can redistribute	 it and/or modify it
  *  under  the terms of	 the GNU General  Public License as published by the
@@ -23,18 +23,18 @@
  *  675 Mass Ave, Cambridge, MA 02139, USA.
  *
  *  Notes :
- * 	au1000 SoC have only one GPIO block : GPIO1
- * 	Au1100, Au15x0, Au12x0 have a second one : GPIO2
+ *	This file must ONLY be built when CONFIG_GPIOLIB=y and
+ *	 CONFIG_ALCHEMY_GPIO_INDIRECT=n, otherwise compilation will fail!
+ *	au1000 SoC have only one GPIO block : GPIO1
+ *	Au1100, Au15x0, Au12x0 have a second one : GPIO2
  */
 
+#include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/types.h>
-#include <linux/platform_device.h>
 #include <linux/gpio.h>
-
-#include <asm/mach-au1x00/au1000.h>
-#include <asm/mach-au1x00/gpio.h>
+#include <asm/mach-au1x00/gpio-au1000.h>
 
 static int gpio2_get(struct gpio_chip *chip, unsigned offset)
 {
@@ -115,12 +115,19 @@ struct gpio_chip alchemy_gpio_chip[] = {
 	},
 };
 
-static int __init alchemy_gpiolib_init(void)
+static int __init alchemy_gpiochip_init(void)
 {
-	gpiochip_add(&alchemy_gpio_chip[0]);
-	if (alchemy_get_cputype() != ALCHEMY_CPU_AU1000)
-		gpiochip_add(&alchemy_gpio_chip[1]);
-
-	return 0;
+	int ret = 0;
+
+	switch (alchemy_get_cputype()) {
+	case ALCHEMY_CPU_AU1000:
+		ret = gpiochip_add(&alchemy_gpio_chip[0]);
+		break;
+	case ALCHEMY_CPU_AU1500...ALCHEMY_CPU_AU1200:
+		ret = gpiochip_add(&alchemy_gpio_chip[0]);
+		ret |= gpiochip_add(&alchemy_gpio_chip[1]);
+		break;
+	}
+	return ret;
 }
-arch_initcall(alchemy_gpiolib_init);
+arch_initcall(alchemy_gpiochip_init);

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 */
 

arch/mips/include/asm/mach-au1x00/gpio.h

+/*
+ * 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_ */