MIPS: Alchemy: Rewrite GPIO support.

The current in-kernel Alchemy GPIO support is far too inflexible for
all my use cases.  To address this, the following changes are made:

* create generic functions which deal with manipulating the on-chip
  GPIO1/2 blocks.  Such functions are universally useful.
* Macros for GPIO2 shared interrupt management and block control.
* support for both built-in CONFIG_GPIOLIB and fast, inlined GPIO macros.

  If CONFIG_GPIOLIB is not enabled, provide linux gpio framework
  compatibility by directly inlining the GPIO1/2 functions.  GPIO access
  is limited to on-chip ones and they can be accessed as documented in
  the datasheets (GPIO0-31 and 200-215).

  If CONFIG_GPIOLIB is selected, two (2) gpio_chip-s, one for GPIO1 and
  one for GPIO2, are registered.  GPIOs can still be accessed by using
  the numberspace established in the databooks.

  However this is not yet flexible enough for my uses:  My Alchemy
  systems have a documented "external" gpio interface (fixed, different
  numberspace) and can support a variety of baseboards, some of which
  are equipped with I2C gpio expanders.  I want to be able to provide
  the default 16 GPIOs of the CPU board numbered as 0..15 and also
  support gpio expanders, if present, starting as gpio16.

  To achieve this, a new Kconfig symbol for Alchemy is introduced,
  CONFIG_ALCHEMY_GPIO_INDIRECT, which boards can enable to signal
  that they don't want the Alchemy numberspace exposed to the outside
  world, but instead want to provide their own.  Boards are now respon-
  sible for providing the linux gpio interface glue code (either in a
  custom gpio.h header (in board include directory) or with gpio_chips).

  To make the board-specific inlined gpio functions work, the MIPS
  Makefile must be changed so that the mach-au1x00/gpio.h header is
  included _after_ the board headers, by moving the inclusion of
  the mach-au1x00/ to the end of the header list.

  See arch/mips/include/asm/mach-au1x00/gpio.h for more info.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 130 insertions, 0 deletions

diff --git a/arch/mips/alchemy/common/gpiolib-au1000.c b/arch/mips/alchemy/common/gpiolib-au1000.c
new file mode 100644
index 00000000000..1bfa91f939f
--- /dev/null
+++ b/arch/mips/alchemy/common/gpiolib-au1000.c
@@ -0,0 +1,130 @@
+/*
+ *  Copyright (C) 2007-2009, OpenWrt.org, Florian Fainelli <florian@openwrt.org>
+ *      GPIOLIB support for Au1000, Au1500, Au1100, Au1550 and Au12x0.
+ *
+ *  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
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
+ *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+ *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
+ *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  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.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ *  Notes :
+ *      au1000 SoC have only one GPIO block : GPIO1
+ *      Au1100, Au15x0, Au12x0 have a second one : GPIO2
+ */
+
+#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>
+
+#if !defined(CONFIG_SOC_AU1000)
+static int gpio2_get(struct gpio_chip *chip, unsigned offset)
+{
+        return alchemy_gpio2_get_value(offset + ALCHEMY_GPIO2_BASE);
+}
+
+static void gpio2_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+        alchemy_gpio2_set_value(offset + ALCHEMY_GPIO2_BASE, value);
+}
+
+static int gpio2_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+        return alchemy_gpio2_direction_input(offset + ALCHEMY_GPIO2_BASE);
+}
+
+static int gpio2_direction_output(struct gpio_chip *chip, unsigned offset,
+                                  int value)
+{
+        return alchemy_gpio2_direction_output(offset + ALCHEMY_GPIO2_BASE,
+                                                value);
+}
+
+static int gpio2_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+        return alchemy_gpio2_to_irq(offset + ALCHEMY_GPIO2_BASE);
+}
+#endif /* !defined(CONFIG_SOC_AU1000) */
+
+static int gpio1_get(struct gpio_chip *chip, unsigned offset)
+{
+        return alchemy_gpio1_get_value(offset + ALCHEMY_GPIO1_BASE);
+}
+
+static void gpio1_set(struct gpio_chip *chip,
+                                unsigned offset, int value)
+{
+        alchemy_gpio1_set_value(offset + ALCHEMY_GPIO1_BASE, value);
+}
+
+static int gpio1_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+        return alchemy_gpio1_direction_input(offset + ALCHEMY_GPIO1_BASE);
+}
+
+static int gpio1_direction_output(struct gpio_chip *chip,
+                                        unsigned offset, int value)
+{
+        return alchemy_gpio1_direction_output(offset + ALCHEMY_GPIO1_BASE,
+                                             value);
+}
+
+static int gpio1_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+        return alchemy_gpio1_to_irq(offset + ALCHEMY_GPIO1_BASE);
+}
+
+struct gpio_chip alchemy_gpio_chip[] = {
+        [0] = {
+                .label                  = "alchemy-gpio1",
+                .direction_input        = gpio1_direction_input,
+                .direction_output       = gpio1_direction_output,
+                .get                    = gpio1_get,
+                .set                    = gpio1_set,
+                .to_irq                 = gpio1_to_irq,
+                .base                   = ALCHEMY_GPIO1_BASE,
+                .ngpio                  = ALCHEMY_GPIO1_NUM,
+        },
+#if !defined(CONFIG_SOC_AU1000)
+        [1] = {
+                .label                  = "alchemy-gpio2",
+                .direction_input        = gpio2_direction_input,
+                .direction_output       = gpio2_direction_output,
+                .get                    = gpio2_get,
+                .set                    = gpio2_set,
+                .to_irq                 = gpio2_to_irq,
+                .base                   = ALCHEMY_GPIO2_BASE,
+                .ngpio                  = ALCHEMY_GPIO2_NUM,
+        },
+#endif
+};
+
+static int __init alchemy_gpiolib_init(void)
+{
+        gpiochip_add(&alchemy_gpio_chip[0]);
+#if !defined(CONFIG_SOC_AU1000)
+        gpiochip_add(&alchemy_gpio_chip[1]);
+#endif
+
+        return 0;
+}
+arch_initcall(alchemy_gpiolib_init);