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/4591
Acked-by: Florian Fainelli <florian@openwrt.org>

5 files changed, 201 insertions, 0 deletions

diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
index 42cdaa9a4d8a..ff3c8a21f10d 100644
--- a/drivers/ssb/Kconfig
+++ b/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
diff --git a/drivers/ssb/Makefile b/drivers/ssb/Makefile
index 656e58b92618..9159ba77c388 100644
--- a/drivers/ssb/Makefile
+++ b/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
diff --git a/drivers/ssb/driver_gpio.c b/drivers/ssb/driver_gpio.c
new file mode 100644
index 000000000000..97ac0a38e3d0
--- /dev/null
+++ b/drivers/ssb/driver_gpio.c
@@ -0,0 +1,176 @@
+/*
+ * 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;
+}
diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
index 6fe2d102734a..87f0ddf4f3f3 100644
--- a/drivers/ssb/main.c
+++ b/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);
diff --git a/drivers/ssb/ssb_private.h b/drivers/ssb/ssb_private.h
index d6a1ba9394d9..463b76a2140b 100644
--- a/drivers/ssb/ssb_private.h
+++ b/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_ */