Re: PPC440EPx gpio driver

["Steven A. Falco" <sfalco@harris.com>]

Thanks again for the comments.  I followed the structure of your
qe_lib/gpio.c; here is the result.  At this point, I've tested input
and output, so it is looking pretty good for me.

I added __init to the ppc4xx_gpio_save_regs because it looks like it is
only needed when first adding the gpios.

Signed-off-by: Steve Falco <sfalco at harris.com>

diff --git a/arch/powerpc/include/asm/ppc4xx.h b/arch/powerpc/include/asm/ppc4xx.h
index 033039a..589ff5c 100644
--- a/arch/powerpc/include/asm/ppc4xx.h
+++ b/arch/powerpc/include/asm/ppc4xx.h
@@ -13,6 +13,30 @@
 #ifndef __ASM_POWERPC_PPC4xx_H__
 #define __ASM_POWERPC_PPC4xx_H__
 
+#include <linux/types.h>
+
+/* GPIO */
+struct ppc4xx_gpio {
+	__be32 gpio_or;
+	__be32 gpio_tcr;
+	__be32 gpio_osrl;
+	__be32 gpio_osrh;
+	__be32 gpio_tsrl;
+	__be32 gpio_tsrh;
+	__be32 gpio_odr;
+	__be32 gpio_ir;
+	__be32 gpio_rr1;
+	__be32 gpio_rr2;
+	__be32 gpio_rr3;
+	__be32 reserved1;
+	__be32 gpio_isr1l;
+	__be32 gpio_isr1h;
+	__be32 gpio_isr2l;
+	__be32 gpio_isr2h;
+	__be32 gpio_isr3l;
+	__be32 gpio_isr3h;
+};
+
 extern void ppc4xx_reset_system(char *cmd);
 
 #endif /* __ASM_POWERPC_PPC4xx_H__ */
diff --git a/arch/powerpc/sysdev/Kconfig b/arch/powerpc/sysdev/Kconfig
index 72fb35b..f4a8edb 100644
--- a/arch/powerpc/sysdev/Kconfig
+++ b/arch/powerpc/sysdev/Kconfig
@@ -6,3 +6,11 @@ config PPC4xx_PCI_EXPRESS
 	bool
 	depends on PCI && 4xx
 	default n
+
+config PPC4xx_GPIO
+	bool "PPC4xx GPIO support"
+	depends on 4xx
+	select ARCH_REQUIRE_GPIOLIB
+	select GENERIC_GPIO
+	help
+	  Enable gpiolib support for PPC4xx based boards
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index a90054b..35d5765 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_OF_RTC)		+= of_rtc.o
 ifeq ($(CONFIG_PCI),y)
 obj-$(CONFIG_4xx)		+= ppc4xx_pci.o
 endif
+obj-$(CONFIG_PPC4xx_GPIO)	+= ppc4xx_gpio.o
 
 # Temporary hack until we have migrated to asm-powerpc
 ifeq ($(ARCH),powerpc)
diff --git a/arch/powerpc/sysdev/ppc4xx_gpio.c b/arch/powerpc/sysdev/ppc4xx_gpio.c
new file mode 100644
index 0000000..95c4204
--- /dev/null
+++ b/arch/powerpc/sysdev/ppc4xx_gpio.c
@@ -0,0 +1,242 @@
+/*
+ * PPC4xx gpio driver
+ *
+ * Copyright (c) 2008 Harris Corporation
+ * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ * Copyright (c) MontaVista Software, Inc. 2008.
+ *
+ * Author: Steve Falco <sfalco@harris.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/gpio.h>
+
+#include <asm/ppc4xx.h>
+
+struct ppc4xx_gpio_chip {
+	struct of_mm_gpio_chip mm_gc;
+	spinlock_t lock;
+	u32 shadow_or;
+	u32 shadow_tcr;
+	u32 shadow_osrl;
+	u32 shadow_osrh;
+	u32 shadow_tsrl;
+	u32 shadow_tsrh;
+	u32 shadow_odr;
+};
+
+/*
+ * GPIO LIB API implementation for GPIOs
+ *
+ * There are a maximum of 64 gpios, spread over two sets of control registers.
+ * The sets are called GPIO0 and GPIO1.  Each set is managed separately, so
+ * there will be two entried in the .dts file.
+ */
+
+static inline struct ppc4xx_gpio_chip *
+to_ppc4xx_gpiochip(struct of_mm_gpio_chip *mm_gc)
+{
+	return container_of(mm_gc, struct ppc4xx_gpio_chip, mm_gc);
+}
+
+static int ppc4xx_gpio_get(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
+	u32 ret;
+
+	ret = (in_be32(&regs->gpio_ir) >> (31 - gpio)) & 1;
+
+	return ret;
+}
+
+static inline void
+__ppc4xx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct ppc4xx_gpio_chip *chip = container_of(mm_gc,
+			struct ppc4xx_gpio_chip, mm_gc);
+	struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
+
+	if (val)
+		chip->shadow_or |= 1 << (31 - gpio);
+	else
+		chip->shadow_or &= ~(1 << (31 - gpio));
+	out_be32(&regs->gpio_or, chip->shadow_or);
+}
+
+static void
+ppc4xx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct ppc4xx_gpio_chip *chip = container_of(mm_gc,
+			struct ppc4xx_gpio_chip, mm_gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	__ppc4xx_gpio_set(gc, gpio, val);
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
+}
+
+static int ppc4xx_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct ppc4xx_gpio_chip *chip = container_of(mm_gc,
+			struct ppc4xx_gpio_chip, mm_gc);
+	struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	/* Disable open-drain function */
+	chip->shadow_odr &= ~(1 << (31 - gpio));
+	out_be32(&regs->gpio_odr, chip->shadow_odr);
+
+	/* Float the pin */
+	chip->shadow_tcr &= ~(1 << (31 - gpio));
+	out_be32(&regs->gpio_tcr, chip->shadow_tcr);
+
+	/* Bits 0-15 use TSRL/OSRL, bits 16-31 use TSRH/OSRH */
+	if (gpio < 16) {
+		chip->shadow_osrl &= ~(3 << ((15 - gpio) * 2));
+		out_be32(&regs->gpio_osrl, chip->shadow_osrl);
+
+		chip->shadow_tsrl &= ~(3 << ((15 - gpio) * 2));
+		out_be32(&regs->gpio_tsrl, chip->shadow_tsrl);
+	} else {
+		chip->shadow_osrh &= ~(3 << ((31 - gpio) * 2));
+		out_be32(&regs->gpio_osrh, chip->shadow_osrh);
+
+		chip->shadow_tsrh &= ~(3 << ((31 - gpio) * 2));
+		out_be32(&regs->gpio_tsrh, chip->shadow_tsrh);
+	}
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	return 0;
+}
+
+static int
+ppc4xx_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct ppc4xx_gpio_chip *chip = container_of(mm_gc,
+			struct ppc4xx_gpio_chip, mm_gc);
+	struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	/* First set initial value */
+	__ppc4xx_gpio_set(gc, gpio, val);
+
+	/* Disable open-drain function */
+	chip->shadow_odr &= ~(1 << (31 - gpio));
+	out_be32(&regs->gpio_odr, chip->shadow_odr);
+
+	/* Drive the pin */
+	chip->shadow_tcr |= (1 << (31 - gpio));
+	out_be32(&regs->gpio_tcr, chip->shadow_tcr);
+
+	/* Bits 0-15 use TSRL, bits 16-31 use TSRH */
+	if (gpio < 16) {
+		chip->shadow_osrl &= ~(3 << ((15 - gpio) * 2));
+		out_be32(&regs->gpio_osrl, chip->shadow_osrl);
+
+		chip->shadow_tsrl &= ~(3 << ((15 - gpio) * 2));
+		out_be32(&regs->gpio_tsrl, chip->shadow_tsrl);
+	} else {
+		chip->shadow_osrh &= ~(3 << ((31 - gpio) * 2));
+		out_be32(&regs->gpio_osrh, chip->shadow_osrh);
+
+		chip->shadow_tsrh &= ~(3 << ((31 - gpio) * 2));
+		out_be32(&regs->gpio_tsrh, chip->shadow_tsrh);
+	}
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
+
+	return 0;
+}
+
+static void __init ppc4xx_gpio_save_regs(struct of_mm_gpio_chip *mm_gc)
+{
+	struct ppc4xx_gpio_chip *chip = to_ppc4xx_gpiochip(mm_gc);
+	struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
+
+	chip->shadow_or = in_be32(&regs->gpio_or);
+	chip->shadow_tcr = in_be32(&regs->gpio_tcr);
+	chip->shadow_osrl = in_be32(&regs->gpio_osrl);
+	chip->shadow_osrh = in_be32(&regs->gpio_osrh);
+	chip->shadow_tsrl = in_be32(&regs->gpio_tsrl);
+	chip->shadow_tsrh = in_be32(&regs->gpio_tsrh);
+	chip->shadow_odr = in_be32(&regs->gpio_odr);
+}
+
+static int __init ppc4xx_add_gpiochips(void)
+{
+	struct device_node *np;
+
+	for_each_compatible_node(np, NULL, "amcc,ppc4xx-gpio") {
+		int ret;
+		struct ppc4xx_gpio_chip *ppc4xx_gc;
+		struct of_mm_gpio_chip *mm_gc;
+		struct of_gpio_chip *of_gc;
+		struct gpio_chip *gc;
+
+		ppc4xx_gc = kzalloc(sizeof(*ppc4xx_gc), GFP_KERNEL);
+		if (!ppc4xx_gc) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		spin_lock_init(&ppc4xx_gc->lock);
+
+		mm_gc = &ppc4xx_gc->mm_gc;
+		of_gc = &mm_gc->of_gc;
+		gc = &of_gc->gc;
+
+		mm_gc->save_regs = ppc4xx_gpio_save_regs;
+		of_gc->gpio_cells = 2;
+		gc->ngpio = 32;
+		gc->direction_input = ppc4xx_gpio_dir_in;
+		gc->direction_output = ppc4xx_gpio_dir_out;
+		gc->get = ppc4xx_gpio_get;
+		gc->set = ppc4xx_gpio_set;
+
+		ret = of_mm_gpiochip_add(np, mm_gc);
+		if (ret)
+			goto err;
+		continue;
+err:
+		pr_err("%s: registration failed with status %d\n",
+		       np->full_name, ret);
+		kfree(ppc4xx_gc);
+		/* try others anyway */
+	}
+	return 0;
+}
+arch_initcall(ppc4xx_add_gpiochips);