Davinci: tnetv107x initial gpio support

This patch adds support for the tnetv107x gpio controller.

Key differences between davinci and tnetv107x controllers:
 - register map - davinci's controller is organized into banks of 32 gpios,
   tnetv107x has a single space with arrays of registers for in, out,
   direction, etc.
 - davinci's controller has separate set/clear registers for output, tnetv107x
   has a single direct mapped register.

This patch does not yet add gpio irq support on this controller.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

3 files changed, 221 insertions, 7 deletions

diff --git a/arch/arm/mach-davinci/Makefile b/arch/arm/mach-davinci/Makefile
index 1c7bcfe122c7..62c51166cacb 100644
--- a/arch/arm/mach-davinci/Makefile
+++ b/arch/arm/mach-davinci/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_ARCH_DAVINCI_DM365)	+= dm365.o devices.o
 obj-$(CONFIG_ARCH_DAVINCI_DA830)        += da830.o devices-da8xx.o
 obj-$(CONFIG_ARCH_DAVINCI_DA850)        += da850.o devices-da8xx.o
 obj-$(CONFIG_ARCH_DAVINCI_TNETV107X)    += tnetv107x.o devices-tnetv107x.o
+obj-$(CONFIG_ARCH_DAVINCI_TNETV107X)    += gpio-tnetv107x.o
 
 obj-$(CONFIG_AINTC)                     += irq.o
 obj-$(CONFIG_CP_INTC)                   += cp_intc.o
diff --git a/arch/arm/mach-davinci/gpio-tnetv107x.c b/arch/arm/mach-davinci/gpio-tnetv107x.c
new file mode 100644
index 000000000000..d10298620e2c
--- /dev/null
+++ b/arch/arm/mach-davinci/gpio-tnetv107x.c
@@ -0,0 +1,205 @@
+/*
+ * Texas Instruments TNETV107X GPIO Controller
+ *
+ * Copyright (C) 2010 Texas Instruments
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/gpio.h>
+
+#include <mach/common.h>
+#include <mach/tnetv107x.h>
+
+struct tnetv107x_gpio_regs {
+        u32     idver;
+        u32     data_in[3];
+        u32     data_out[3];
+        u32     direction[3];
+        u32     enable[3];
+};
+
+#define gpio_reg_index(gpio)    ((gpio) >> 5)
+#define gpio_reg_bit(gpio)      BIT((gpio) & 0x1f)
+
+#define gpio_reg_rmw(reg, mask, val)    \
+        __raw_writel((__raw_readl(reg) & ~(mask)) | (val), (reg))
+
+#define gpio_reg_set_bit(reg, gpio)     \
+        gpio_reg_rmw((reg) + gpio_reg_index(gpio), 0, gpio_reg_bit(gpio))
+
+#define gpio_reg_clear_bit(reg, gpio)   \
+        gpio_reg_rmw((reg) + gpio_reg_index(gpio), gpio_reg_bit(gpio), 0)
+
+#define gpio_reg_get_bit(reg, gpio)     \
+        (__raw_readl((reg) + gpio_reg_index(gpio)) & gpio_reg_bit(gpio))
+
+#define chip2controller(chip)           \
+        container_of(chip, struct davinci_gpio_controller, chip)
+
+#define TNETV107X_GPIO_CTLRS    DIV_ROUND_UP(TNETV107X_N_GPIO, 32)
+
+static struct davinci_gpio_controller chips[TNETV107X_GPIO_CTLRS];
+
+static int tnetv107x_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+        struct davinci_gpio_controller *ctlr = chip2controller(chip);
+        struct tnetv107x_gpio_regs __iomem *regs = ctlr->regs;
+        unsigned gpio = chip->base + offset;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ctlr->lock, flags);
+
+        gpio_reg_set_bit(&regs->enable, gpio);
+
+        spin_unlock_irqrestore(&ctlr->lock, flags);
+
+        return 0;
+}
+
+static void tnetv107x_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+        struct davinci_gpio_controller *ctlr = chip2controller(chip);
+        struct tnetv107x_gpio_regs __iomem *regs = ctlr->regs;
+        unsigned gpio = chip->base + offset;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ctlr->lock, flags);
+
+        gpio_reg_clear_bit(&regs->enable, gpio);
+
+        spin_unlock_irqrestore(&ctlr->lock, flags);
+}
+
+static int tnetv107x_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
+{
+        struct davinci_gpio_controller *ctlr = chip2controller(chip);
+        struct tnetv107x_gpio_regs __iomem *regs = ctlr->regs;
+        unsigned gpio = chip->base + offset;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ctlr->lock, flags);
+
+        gpio_reg_set_bit(&regs->direction, gpio);
+
+        spin_unlock_irqrestore(&ctlr->lock, flags);
+
+        return 0;
+}
+
+static int tnetv107x_gpio_dir_out(struct gpio_chip *chip,
+                unsigned offset, int value)
+{
+        struct davinci_gpio_controller *ctlr = chip2controller(chip);
+        struct tnetv107x_gpio_regs __iomem *regs = ctlr->regs;
+        unsigned gpio = chip->base + offset;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ctlr->lock, flags);
+
+        if (value)
+                gpio_reg_set_bit(&regs->data_out, gpio);
+        else
+                gpio_reg_clear_bit(&regs->data_out, gpio);
+
+        gpio_reg_clear_bit(&regs->direction, gpio);
+
+        spin_unlock_irqrestore(&ctlr->lock, flags);
+
+        return 0;
+}
+
+static int tnetv107x_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+        struct davinci_gpio_controller *ctlr = chip2controller(chip);
+        struct tnetv107x_gpio_regs __iomem *regs = ctlr->regs;
+        unsigned gpio = chip->base + offset;
+        int ret;
+
+        ret = gpio_reg_get_bit(&regs->data_in, gpio);
+
+        return ret ? 1 : 0;
+}
+
+static void tnetv107x_gpio_set(struct gpio_chip *chip,
+                unsigned offset, int value)
+{
+        struct davinci_gpio_controller *ctlr = chip2controller(chip);
+        struct tnetv107x_gpio_regs __iomem *regs = ctlr->regs;
+        unsigned gpio = chip->base + offset;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ctlr->lock, flags);
+
+        if (value)
+                gpio_reg_set_bit(&regs->data_out, gpio);
+        else
+                gpio_reg_clear_bit(&regs->data_out, gpio);
+
+        spin_unlock_irqrestore(&ctlr->lock, flags);
+}
+
+static int __init tnetv107x_gpio_setup(void)
+{
+        int i, base;
+        unsigned ngpio;
+        struct davinci_soc_info *soc_info = &davinci_soc_info;
+        struct tnetv107x_gpio_regs *regs;
+        struct davinci_gpio_controller *ctlr;
+
+        if (soc_info->gpio_type != GPIO_TYPE_TNETV107X)
+                return 0;
+
+        ngpio = soc_info->gpio_num;
+        if (ngpio == 0) {
+                pr_err("GPIO setup:  how many GPIOs?\n");
+                return -EINVAL;
+        }
+
+        if (WARN_ON(TNETV107X_N_GPIO < ngpio))
+                ngpio = TNETV107X_N_GPIO;
+
+        regs = ioremap(soc_info->gpio_base, SZ_4K);
+        if (WARN_ON(!regs))
+                return -EINVAL;
+
+        for (i = 0, base = 0; base < ngpio; i++, base += 32) {
+                ctlr = &chips[i];
+
+                ctlr->chip.label        = "tnetv107x";
+                ctlr->chip.can_sleep    = 0;
+                ctlr->chip.base         = base;
+                ctlr->chip.ngpio        = ngpio - base;
+                if (ctlr->chip.ngpio > 32)
+                        ctlr->chip.ngpio = 32;
+
+                ctlr->chip.request              = tnetv107x_gpio_request;
+                ctlr->chip.free                 = tnetv107x_gpio_free;
+                ctlr->chip.direction_input      = tnetv107x_gpio_dir_in;
+                ctlr->chip.get                  = tnetv107x_gpio_get;
+                ctlr->chip.direction_output     = tnetv107x_gpio_dir_out;
+                ctlr->chip.set                  = tnetv107x_gpio_set;
+
+                spin_lock_init(&ctlr->lock);
+
+                ctlr->regs      = regs;
+                ctlr->set_data  = &regs->data_out[i];
+                ctlr->clr_data  = &regs->data_out[i];
+                ctlr->in_data   = &regs->data_in[i];
+
+                gpiochip_add(&ctlr->chip);
+        }
+
+        soc_info->gpio_ctlrs = chips;
+        soc_info->gpio_ctlrs_num = DIV_ROUND_UP(ngpio, 32);
+        return 0;
+}
+pure_initcall(tnetv107x_gpio_setup);
diff --git a/arch/arm/mach-davinci/include/mach/gpio.h b/arch/arm/mach-davinci/include/mach/gpio.h
index 504cc180a60b..fbece126c2bf 100644
--- a/arch/arm/mach-davinci/include/mach/gpio.h
+++ b/arch/arm/mach-davinci/include/mach/gpio.h
@@ -25,6 +25,7 @@
 
 enum davinci_gpio_type {
         GPIO_TYPE_DAVINCI = 0,
+        GPIO_TYPE_TNETV107X,
 };
 
 /*
@@ -87,9 +88,13 @@ static inline u32 __gpio_mask(unsigned gpio)
         return 1 << (gpio % 32);
 }
 
-/* The get/set/clear functions will inline when called with constant
+/*
+ * The get/set/clear functions will inline when called with constant
  * parameters referencing built-in GPIOs, for low-overhead bitbanging.
  *
+ * gpio_set_value() will inline only on traditional Davinci style controllers
+ * with distinct set/clear registers.
+ *
  * Otherwise, calls with variable parameters or referencing external
  * GPIOs (e.g. on GPIO expander chips) use outlined functions.
  */
@@ -100,12 +105,15 @@ static inline void gpio_set_value(unsigned gpio, int value)
                 u32                             mask;
 
                 ctlr = __gpio_to_controller(gpio);
-                mask = __gpio_mask(gpio);
-                if (value)
-                        __raw_writel(mask, ctlr->set_data);
-                else
-                        __raw_writel(mask, ctlr->clr_data);
-                return;
+
+                if (ctlr->set_data != ctlr->clr_data) {
+                        mask = __gpio_mask(gpio);
+                        if (value)
+                                __raw_writel(mask, ctlr->set_data);
+                        else
+                                __raw_writel(mask, ctlr->clr_data);
+                        return;
+                }
         }
 
         __gpio_set_value(gpio, value);