gpio MIPS/OCTEON: Add a driver for OCTEON's on-chip GPIO pins.

The SOCs in the OCTEON family have 16 (or in some cases 20) on-chip
GPIO pins, this driver handles them all.  Configuring the pins as
interrupt sources is handled elsewhere (OCTEON's irq handling code).

Signed-off-by: David Daney <david.daney@cavium.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/5633/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 166 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b2450ba14138..b21b7a2d1c3d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -193,6 +193,14 @@ config GPIO_MXS
         select GPIO_GENERIC
         select GENERIC_IRQ_CHIP
 
+config GPIO_OCTEON
+        tristate "Cavium OCTEON GPIO"
+        depends on GPIOLIB && CAVIUM_OCTEON_SOC
+        default y
+        help
+          Say yes here to support the on-chip GPIO lines on the OCTEON
+          family of SOCs.
+
 config GPIO_PL061
         bool "PrimeCell PL061 GPIO support"
         depends on ARM && ARM_AMBA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index ef3e983a2f1e..e7fd9800dad4 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -50,6 +50,7 @@ obj-$(CONFIG_GPIO_MSM_V2)	+= gpio-msm-v2.o
 obj-$(CONFIG_GPIO_MVEBU)        += gpio-mvebu.o
 obj-$(CONFIG_GPIO_MXC)          += gpio-mxc.o
 obj-$(CONFIG_GPIO_MXS)          += gpio-mxs.o
+obj-$(CONFIG_GPIO_OCTEON)       += gpio-octeon.o
 obj-$(CONFIG_ARCH_OMAP)         += gpio-omap.o
 obj-$(CONFIG_GPIO_PCA953X)      += gpio-pca953x.o
 obj-$(CONFIG_GPIO_PCF857X)      += gpio-pcf857x.o
diff --git a/drivers/gpio/gpio-octeon.c b/drivers/gpio/gpio-octeon.c
new file mode 100644
index 000000000000..71a4a318315d
--- /dev/null
+++ b/drivers/gpio/gpio-octeon.c
@@ -0,0 +1,157 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011, 2012 Cavium Inc.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+
+#include <asm/octeon/octeon.h>
+#include <asm/octeon/cvmx-gpio-defs.h>
+
+#define RX_DAT 0x80
+#define TX_SET 0x88
+#define TX_CLEAR 0x90
+/*
+ * The address offset of the GPIO configuration register for a given
+ * line.
+ */
+static unsigned int bit_cfg_reg(unsigned int offset)
+{
+        /*
+         * The register stride is 8, with a discontinuity after the
+         * first 16.
+         */
+        if (offset < 16)
+                return 8 * offset;
+        else
+                return 8 * (offset - 16) + 0x100;
+}
+
+struct octeon_gpio {
+        struct gpio_chip chip;
+        u64 register_base;
+};
+
+static int octeon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
+{
+        struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
+
+        cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), 0);
+        return 0;
+}
+
+static void octeon_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+        struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
+        u64 mask = 1ull << offset;
+        u64 reg = gpio->register_base + (value ? TX_SET : TX_CLEAR);
+        cvmx_write_csr(reg, mask);
+}
+
+static int octeon_gpio_dir_out(struct gpio_chip *chip, unsigned offset,
+                               int value)
+{
+        struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
+        union cvmx_gpio_bit_cfgx cfgx;
+
+        octeon_gpio_set(chip, offset, value);
+
+        cfgx.u64 = 0;
+        cfgx.s.tx_oe = 1;
+
+        cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), cfgx.u64);
+        return 0;
+}
+
+static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+        struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
+        u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT);
+
+        return ((1ull << offset) & read_bits) != 0;
+}
+
+static int octeon_gpio_probe(struct platform_device *pdev)
+{
+        struct octeon_gpio *gpio;
+        struct gpio_chip *chip;
+        struct resource *res_mem;
+        int err = 0;
+
+        gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+        if (!gpio)
+                return -ENOMEM;
+        chip = &gpio->chip;
+
+        res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (res_mem == NULL) {
+                dev_err(&pdev->dev, "found no memory resource\n");
+                err = -ENXIO;
+                goto out;
+        }
+        if (!devm_request_mem_region(&pdev->dev, res_mem->start,
+                                        resource_size(res_mem),
+                                     res_mem->name)) {
+                dev_err(&pdev->dev, "request_mem_region failed\n");
+                err = -ENXIO;
+                goto out;
+        }
+        gpio->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start,
+                                                resource_size(res_mem));
+
+        pdev->dev.platform_data = chip;
+        chip->label = "octeon-gpio";
+        chip->dev = &pdev->dev;
+        chip->owner = THIS_MODULE;
+        chip->base = 0;
+        chip->can_sleep = 0;
+        chip->ngpio = 20;
+        chip->direction_input = octeon_gpio_dir_in;
+        chip->get = octeon_gpio_get;
+        chip->direction_output = octeon_gpio_dir_out;
+        chip->set = octeon_gpio_set;
+        err = gpiochip_add(chip);
+        if (err)
+                goto out;
+
+        dev_info(&pdev->dev, "OCTEON GPIO driver probed.\n");
+out:
+        return err;
+}
+
+static int octeon_gpio_remove(struct platform_device *pdev)
+{
+        struct gpio_chip *chip = pdev->dev.platform_data;
+        return gpiochip_remove(chip);
+}
+
+static struct of_device_id octeon_gpio_match[] = {
+        {
+                .compatible = "cavium,octeon-3860-gpio",
+        },
+        {},
+};
+MODULE_DEVICE_TABLE(of, octeon_gpio_match);
+
+static struct platform_driver octeon_gpio_driver = {
+        .driver = {
+                .name           = "octeon_gpio",
+                .owner          = THIS_MODULE,
+                .of_match_table = octeon_gpio_match,
+        },
+        .probe          = octeon_gpio_probe,
+        .remove         = octeon_gpio_remove,
+};
+
+module_platform_driver(octeon_gpio_driver);
+
+MODULE_DESCRIPTION("Cavium Inc. OCTEON GPIO Driver");
+MODULE_AUTHOR("David Daney");
+MODULE_LICENSE("GPL");