ssb: add GPIO driver

Register a GPIO driver to access the GPIOs provided by the chip.
The GPIOs of the SoC should always start at 0 and the other GPIOs could
start at a random position. There is just one SoC in a system and when
they start at 0 the number is predictable.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: http://patchwork.linux-mips.org/patch/4591Acked-by: Florian Fainelli <florian@openwrt.org>

drivers/ssb/Kconfig

@@ -160,4 +160,13 @@ config SSB_DRIVER_GIGE
 
 	  If unsure, say N
 
+config SSB_DRIVER_GPIO
+	bool "SSB GPIO driver"
+	depends on SSB
+	select GPIOLIB
+	help
+	  Driver to provide access to the GPIO pins on the bus.
+
+	  If unsure, say N
+
 endmenu

drivers/ssb/Makefile

@@ -15,6 +15,7 @@ ssb-$(CONFIG_SSB_DRIVER_MIPS)		+= driver_mipscore.o
 ssb-$(CONFIG_SSB_DRIVER_EXTIF)		+= driver_extif.o
 ssb-$(CONFIG_SSB_DRIVER_PCICORE)	+= driver_pcicore.o
 ssb-$(CONFIG_SSB_DRIVER_GIGE)		+= driver_gige.o
+ssb-$(CONFIG_SSB_DRIVER_GPIO)		+= driver_gpio.o
 
 # b43 pci-ssb-bridge driver
 # Not strictly a part of SSB, but kept here for convenience

drivers/ssb/driver_gpio.c

+/*
+ * Sonics Silicon Backplane
+ * GPIO driver
+ *
+ * Copyright 2011, Broadcom Corporation
+ * Copyright 2012, Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include <linux/gpio.h>
+#include <linux/export.h>
+#include <linux/ssb/ssb.h>
+
+#include "ssb_private.h"
+
+static struct ssb_bus *ssb_gpio_get_bus(struct gpio_chip *chip)
+{
+	return container_of(chip, struct ssb_bus, gpio);
+}
+
+static int ssb_gpio_chipco_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	return !!ssb_chipco_gpio_in(&bus->chipco, 1 << gpio);
+}
+
+static void ssb_gpio_chipco_set_value(struct gpio_chip *chip, unsigned gpio,
+				      int value)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);
+}
+
+static int ssb_gpio_chipco_direction_input(struct gpio_chip *chip,
+					   unsigned gpio)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 0);
+	return 0;
+}
+
+static int ssb_gpio_chipco_direction_output(struct gpio_chip *chip,
+					    unsigned gpio, int value)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_chipco_gpio_outen(&bus->chipco, 1 << gpio, 1 << gpio);
+	ssb_chipco_gpio_out(&bus->chipco, 1 << gpio, value ? 1 << gpio : 0);
+	return 0;
+}
+
+static int ssb_gpio_chipco_request(struct gpio_chip *chip, unsigned gpio)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_chipco_gpio_control(&bus->chipco, 1 << gpio, 0);
+	/* clear pulldown */
+	ssb_chipco_gpio_pulldown(&bus->chipco, 1 << gpio, 0);
+	/* Set pullup */
+	ssb_chipco_gpio_pullup(&bus->chipco, 1 << gpio, 1 << gpio);
+
+	return 0;
+}
+
+static void ssb_gpio_chipco_free(struct gpio_chip *chip, unsigned gpio)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	/* clear pullup */
+	ssb_chipco_gpio_pullup(&bus->chipco, 1 << gpio, 0);
+}
+
+static int ssb_gpio_chipco_init(struct ssb_bus *bus)
+{
+	struct gpio_chip *chip = &bus->gpio;
+
+	chip->label		= "ssb_chipco_gpio";
+	chip->owner		= THIS_MODULE;
+	chip->request		= ssb_gpio_chipco_request;
+	chip->free		= ssb_gpio_chipco_free;
+	chip->get		= ssb_gpio_chipco_get_value;
+	chip->set		= ssb_gpio_chipco_set_value;
+	chip->direction_input	= ssb_gpio_chipco_direction_input;
+	chip->direction_output	= ssb_gpio_chipco_direction_output;
+	chip->ngpio		= 16;
+	/* There is just one SoC in one device and its GPIO addresses should be
+	 * deterministic to address them more easily. The other buses could get
+	 * a random base number. */
+	if (bus->bustype == SSB_BUSTYPE_SSB)
+		chip->base		= 0;
+	else
+		chip->base		= -1;
+
+	return gpiochip_add(chip);
+}
+
+#ifdef CONFIG_SSB_DRIVER_EXTIF
+
+static int ssb_gpio_extif_get_value(struct gpio_chip *chip, unsigned gpio)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	return !!ssb_extif_gpio_in(&bus->extif, 1 << gpio);
+}
+
+static void ssb_gpio_extif_set_value(struct gpio_chip *chip, unsigned gpio,
+				     int value)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);
+}
+
+static int ssb_gpio_extif_direction_input(struct gpio_chip *chip,
+					  unsigned gpio)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 0);
+	return 0;
+}
+
+static int ssb_gpio_extif_direction_output(struct gpio_chip *chip,
+					   unsigned gpio, int value)
+{
+	struct ssb_bus *bus = ssb_gpio_get_bus(chip);
+
+	ssb_extif_gpio_outen(&bus->extif, 1 << gpio, 1 << gpio);
+	ssb_extif_gpio_out(&bus->extif, 1 << gpio, value ? 1 << gpio : 0);
+	return 0;
+}
+
+static int ssb_gpio_extif_init(struct ssb_bus *bus)
+{
+	struct gpio_chip *chip = &bus->gpio;
+
+	chip->label		= "ssb_extif_gpio";
+	chip->owner		= THIS_MODULE;
+	chip->get		= ssb_gpio_extif_get_value;
+	chip->set		= ssb_gpio_extif_set_value;
+	chip->direction_input	= ssb_gpio_extif_direction_input;
+	chip->direction_output	= ssb_gpio_extif_direction_output;
+	chip->ngpio		= 5;
+	/* There is just one SoC in one device and its GPIO addresses should be
+	 * deterministic to address them more easily. The other buses could get
+	 * a random base number. */
+	if (bus->bustype == SSB_BUSTYPE_SSB)
+		chip->base		= 0;
+	else
+		chip->base		= -1;
+
+	return gpiochip_add(chip);
+}
+
+#else
+static int ssb_gpio_extif_init(struct ssb_bus *bus)
+{
+	return -ENOTSUPP;
+}
+#endif
+
+int ssb_gpio_init(struct ssb_bus *bus)
+{
+	if (ssb_chipco_available(&bus->chipco))
+		return ssb_gpio_chipco_init(bus);
+	else if (ssb_extif_available(&bus->extif))
+		return ssb_gpio_extif_init(bus);
+	else
+		SSB_WARN_ON(1);
+
+	return -1;
+}

drivers/ssb/main.c

@@ -798,6 +798,12 @@ static int __devinit ssb_bus_register(struct ssb_bus *bus,
 	ssb_chipcommon_init(&bus->chipco);
 	ssb_extif_init(&bus->extif);
 	ssb_mipscore_init(&bus->mipscore);
+	err = ssb_gpio_init(bus);
+	if (err == -ENOTSUPP)
+		ssb_dprintk(KERN_DEBUG PFX "GPIO driver not activated\n");
+	else if (err)
+		ssb_dprintk(KERN_ERR PFX
+			   "Error registering GPIO driver: %i\n", err);
 	err = ssb_fetch_invariants(bus, get_invariants);
 	if (err) {
 		ssb_bus_may_powerdown(bus);

drivers/ssb/ssb_private.h

@@ -219,4 +219,13 @@ static inline void ssb_extif_init(struct ssb_extif *extif)
 }
 #endif
 
+#ifdef CONFIG_SSB_DRIVER_GPIO
+extern int ssb_gpio_init(struct ssb_bus *bus);
+#else /* CONFIG_SSB_DRIVER_GPIO */
+static inline int ssb_gpio_init(struct ssb_bus *bus)
+{
+	return -ENOTSUPP;
+}
+#endif /* CONFIG_SSB_DRIVER_GPIO */
+
 #endif /* LINUX_SSB_PRIVATE_H_ */

include/linux/ssb/ssb.h

@@ -6,6 +6,7 @@
 #include <linux/types.h>
 #include <linux/spinlock.h>
 #include <linux/pci.h>
+#include <linux/gpio.h>
 #include <linux/mod_devicetable.h>
 #include <linux/dma-mapping.h>
 
@@ -433,6 +434,9 @@ struct ssb_bus {
 	/* Lock for GPIO register access. */
 	spinlock_t gpio_lock;
 #endif /* EMBEDDED */
+#ifdef CONFIG_SSB_DRIVER_GPIO
+	struct gpio_chip gpio;
+#endif /* DRIVER_GPIO */
 
 	/* Internal-only stuff follows. Do not touch. */
 	struct list_head list;