gpio-tz1090-pdc: add TZ1090 PDC gpio driver

Add a GPIO driver for the low-power Powerdown Controller GPIOs in the
TZ1090 SoC.

The driver is instantiated by device tree and supports interrupts for
the SysWake GPIOs only.

Changes in v4:
 - fix typos in DT bindings compatible properties
 - reference Documentation/devicetree/bindings/gpio/gpio.txt in
   gpio-ranges description in DT bindings
 - fix gpio-ranges examples in DT bindings (it must now have 3 cells)

Changes in v3:
 - separated from irq-imgpdc and removed arch/metag changes to allow
   these patches to go upstream separately via the pinctrl[/gpio] trees
   (particularly the pinctrl drivers depend on the new pinconf DT
   bindings).
 - some s/unsigned/unsigned int/.
 - gpio-tz1090*: refer to <dt-bindings/gpio/gpio.h> and
   <dt-bindings/interrupt-controller/irq.h> flags in bindings.
 - gpio-tz1090*: move initcall from postcore to subsys.

Changes in v2:
 - gpio-tz1090-pdc: remove references to Linux flags in dt bindings
 - gpio-tz1090-pdc: make use of BIT() from linux/bitops.h
 - gpio-tz1090-pdc: make register accessors inline to match pinctrl
 - gpio-tz1090-pdc: update gpio-ranges to use 3 cells after recent ABI
   breakage

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 251 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e9761641f149..4e44cdcf3612 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -249,6 +249,13 @@ config GPIO_TZ1090
         help
           Say yes here to support Toumaz Xenif TZ1090 GPIOs.
 
+config GPIO_TZ1090_PDC
+        bool "Toumaz Xenif TZ1090 PDC GPIO support"
+        depends on SOC_TZ1090
+        default y
+        help
+          Say yes here to support Toumaz Xenif TZ1090 PDC GPIOs.
+
 config GPIO_XILINX
         bool "Xilinx GPIO support"
         depends on PPC_OF || MICROBLAZE || ARCH_ZYNQ
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 2baf456392f9..fa97bf8698ed 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -80,6 +80,7 @@ obj-$(CONFIG_GPIO_TS5500)	+= gpio-ts5500.o
 obj-$(CONFIG_GPIO_TWL4030)      += gpio-twl4030.o
 obj-$(CONFIG_GPIO_TWL6040)      += gpio-twl6040.o
 obj-$(CONFIG_GPIO_TZ1090)       += gpio-tz1090.o
+obj-$(CONFIG_GPIO_TZ1090_PDC)   += gpio-tz1090-pdc.o
 obj-$(CONFIG_GPIO_UCB1400)      += gpio-ucb1400.o
 obj-$(CONFIG_GPIO_VIPERBOARD)   += gpio-viperboard.o
 obj-$(CONFIG_GPIO_VR41XX)       += gpio-vr41xx.o
diff --git a/drivers/gpio/gpio-tz1090-pdc.c b/drivers/gpio/gpio-tz1090-pdc.c
new file mode 100644
index 000000000000..f512da299b3d
--- /dev/null
+++ b/drivers/gpio/gpio-tz1090-pdc.c
@@ -0,0 +1,243 @@
+/*
+ * Toumaz Xenif TZ1090 PDC GPIO handling.
+ *
+ * Copyright (C) 2012-2013 Imagination Technologies Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/syscore_ops.h>
+#include <asm/global_lock.h>
+
+/* Register offsets from SOC_GPIO_CONTROL0 */
+#define REG_SOC_GPIO_CONTROL0   0x00
+#define REG_SOC_GPIO_CONTROL1   0x04
+#define REG_SOC_GPIO_CONTROL2   0x08
+#define REG_SOC_GPIO_CONTROL3   0x0c
+#define REG_SOC_GPIO_STATUS     0x80
+
+/* PDC GPIOs go after normal GPIOs */
+#define GPIO_PDC_BASE           90
+#define GPIO_PDC_NGPIO          7
+
+/* Out of PDC gpios, only syswakes have irqs */
+#define GPIO_PDC_IRQ_FIRST      2
+#define GPIO_PDC_NIRQ           3
+
+/**
+ * struct tz1090_pdc_gpio - GPIO bank private data
+ * @chip:       Generic GPIO chip for GPIO bank
+ * @reg:        Base of registers, offset for this GPIO bank
+ * @irq:        IRQ numbers for Syswake GPIOs
+ *
+ * This is the main private data for the PDC GPIO driver. It encapsulates a
+ * gpio_chip, and the callbacks for the gpio_chip can access the private data
+ * with the to_pdc() macro below.
+ */
+struct tz1090_pdc_gpio {
+        struct gpio_chip chip;
+        void __iomem *reg;
+        int irq[GPIO_PDC_NIRQ];
+};
+#define to_pdc(c)       container_of(c, struct tz1090_pdc_gpio, chip)
+
+/* Register accesses into the PDC MMIO area */
+
+static inline void pdc_write(struct tz1090_pdc_gpio *priv, unsigned int reg_offs,
+                      unsigned int data)
+{
+        writel(data, priv->reg + reg_offs);
+}
+
+static inline unsigned int pdc_read(struct tz1090_pdc_gpio *priv,
+                             unsigned int reg_offs)
+{
+        return readl(priv->reg + reg_offs);
+}
+
+/* Generic GPIO interface */
+
+static int tz1090_pdc_gpio_direction_input(struct gpio_chip *chip,
+                                           unsigned int offset)
+{
+        struct tz1090_pdc_gpio *priv = to_pdc(chip);
+        u32 value;
+        int lstat;
+
+        __global_lock2(lstat);
+        value = pdc_read(priv, REG_SOC_GPIO_CONTROL1);
+        value |= BIT(offset);
+        pdc_write(priv, REG_SOC_GPIO_CONTROL1, value);
+        __global_unlock2(lstat);
+
+        return 0;
+}
+
+static int tz1090_pdc_gpio_direction_output(struct gpio_chip *chip,
+                                            unsigned int offset,
+                                            int output_value)
+{
+        struct tz1090_pdc_gpio *priv = to_pdc(chip);
+        u32 value;
+        int lstat;
+
+        __global_lock2(lstat);
+        /* EXT_POWER doesn't seem to have an output value bit */
+        if (offset < 6) {
+                value = pdc_read(priv, REG_SOC_GPIO_CONTROL0);
+                if (output_value)
+                        value |= BIT(offset);
+                else
+                        value &= ~BIT(offset);
+                pdc_write(priv, REG_SOC_GPIO_CONTROL0, value);
+        }
+
+        value = pdc_read(priv, REG_SOC_GPIO_CONTROL1);
+        value &= ~BIT(offset);
+        pdc_write(priv, REG_SOC_GPIO_CONTROL1, value);
+        __global_unlock2(lstat);
+
+        return 0;
+}
+
+static int tz1090_pdc_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+        struct tz1090_pdc_gpio *priv = to_pdc(chip);
+        return pdc_read(priv, REG_SOC_GPIO_STATUS) & BIT(offset);
+}
+
+static void tz1090_pdc_gpio_set(struct gpio_chip *chip, unsigned int offset,
+                                int output_value)
+{
+        struct tz1090_pdc_gpio *priv = to_pdc(chip);
+        u32 value;
+        int lstat;
+
+        /* EXT_POWER doesn't seem to have an output value bit */
+        if (offset >= 6)
+                return;
+
+        __global_lock2(lstat);
+        value = pdc_read(priv, REG_SOC_GPIO_CONTROL0);
+        if (output_value)
+                value |= BIT(offset);
+        else
+                value &= ~BIT(offset);
+        pdc_write(priv, REG_SOC_GPIO_CONTROL0, value);
+        __global_unlock2(lstat);
+}
+
+static int tz1090_pdc_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+        return pinctrl_request_gpio(chip->base + offset);
+}
+
+static void tz1090_pdc_gpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+        pinctrl_free_gpio(chip->base + offset);
+}
+
+static int tz1090_pdc_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
+{
+        struct tz1090_pdc_gpio *priv = to_pdc(chip);
+        unsigned int syswake = offset - GPIO_PDC_IRQ_FIRST;
+        int irq;
+
+        /* only syswakes have irqs */
+        if (syswake >= GPIO_PDC_NIRQ)
+                return -EINVAL;
+
+        irq = priv->irq[syswake];
+        if (!irq)
+                return -EINVAL;
+
+        return irq;
+}
+
+static int tz1090_pdc_gpio_probe(struct platform_device *pdev)
+{
+        struct device_node *np = pdev->dev.of_node;
+        struct resource *res_regs;
+        struct tz1090_pdc_gpio *priv;
+        unsigned int i;
+
+        if (!np) {
+                dev_err(&pdev->dev, "must be instantiated via devicetree\n");
+                return -ENOENT;
+        }
+
+        res_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res_regs) {
+                dev_err(&pdev->dev, "cannot find registers resource\n");
+                return -ENOENT;
+        }
+
+        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+        if (!priv) {
+                dev_err(&pdev->dev, "unable to allocate driver data\n");
+                return -ENOMEM;
+        }
+
+        /* Ioremap the registers */
+        priv->reg = devm_ioremap(&pdev->dev, res_regs->start,
+                                 res_regs->end - res_regs->start);
+        if (!priv->reg) {
+                dev_err(&pdev->dev, "unable to ioremap registers\n");
+                return -ENOMEM;
+        }
+
+        /* Set up GPIO chip */
+        priv->chip.label                = "tz1090-pdc-gpio";
+        priv->chip.dev                  = &pdev->dev;
+        priv->chip.direction_input      = tz1090_pdc_gpio_direction_input;
+        priv->chip.direction_output     = tz1090_pdc_gpio_direction_output;
+        priv->chip.get                  = tz1090_pdc_gpio_get;
+        priv->chip.set                  = tz1090_pdc_gpio_set;
+        priv->chip.free                 = tz1090_pdc_gpio_free;
+        priv->chip.request              = tz1090_pdc_gpio_request;
+        priv->chip.to_irq               = tz1090_pdc_gpio_to_irq;
+        priv->chip.of_node              = np;
+
+        /* GPIO numbering */
+        priv->chip.base                 = GPIO_PDC_BASE;
+        priv->chip.ngpio                = GPIO_PDC_NGPIO;
+
+        /* Map the syswake irqs */
+        for (i = 0; i < GPIO_PDC_NIRQ; ++i)
+                priv->irq[i] = irq_of_parse_and_map(np, i);
+
+        /* Add the GPIO bank */
+        gpiochip_add(&priv->chip);
+
+        return 0;
+}
+
+static struct of_device_id tz1090_pdc_gpio_of_match[] = {
+        { .compatible = "img,tz1090-pdc-gpio" },
+        { },
+};
+
+static struct platform_driver tz1090_pdc_gpio_driver = {
+        .driver = {
+                .name           = "tz1090-pdc-gpio",
+                .owner          = THIS_MODULE,
+                .of_match_table = tz1090_pdc_gpio_of_match,
+        },
+        .probe          = tz1090_pdc_gpio_probe,
+};
+
+static int __init tz1090_pdc_gpio_init(void)
+{
+        return platform_driver_register(&tz1090_pdc_gpio_driver);
+}
+subsys_initcall(tz1090_pdc_gpio_init);