Atheros AR2315 SoC have a builtin GPIO controller, which could be
accessed via memory mapped registers. This patch adds new driver
for them.

Signed-off-by: Sergey Ryazanov <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: Alexandre Courbot <[email protected]>
Cc: [email protected]
---

Changes since RFC:
  - fix chip name, this patch adds AR2315 GPIO controller driver
  - use dynamic IRQ numbers allocation
  - move device registration to separate patch

 drivers/gpio/Kconfig       |   7 ++
 drivers/gpio/Makefile      |   1 +
 drivers/gpio/gpio-ar2315.c | 232 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 240 insertions(+)
 create mode 100644 drivers/gpio/gpio-ar2315.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 7ce411b..0ceb4ba 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -112,6 +112,13 @@ config GPIO_MAX730X
 
 comment "Memory mapped GPIO drivers:"
 
+config GPIO_AR2315
+       bool "AR2315 SoC GPIO support"
+       default y if SOC_AR2315
+       depends on SOC_AR2315
+       help
+         Say yes here to enable GPIO support for Atheros AR2315+ SoCs.
+
 config GPIO_AR5312
        bool "AR5312 SoC GPIO support"
        default y if SOC_AR5312
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fae00f4..9a3a136 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_GPIO_ADNP)               += gpio-adnp.o
 obj-$(CONFIG_GPIO_ADP5520)     += gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)     += gpio-adp5588.o
 obj-$(CONFIG_GPIO_AMD8111)     += gpio-amd8111.o
+obj-$(CONFIG_GPIO_AR2315)      += gpio-ar2315.o
 obj-$(CONFIG_GPIO_AR5312)      += gpio-ar5312.o
 obj-$(CONFIG_GPIO_ARIZONA)     += gpio-arizona.o
 obj-$(CONFIG_GPIO_BCM_KONA)    += gpio-bcm-kona.o
diff --git a/drivers/gpio/gpio-ar2315.c b/drivers/gpio/gpio-ar2315.c
new file mode 100644
index 0000000..2a6caaf
--- /dev/null
+++ b/drivers/gpio/gpio-ar2315.c
@@ -0,0 +1,232 @@
+/*
+ * 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) 2003 Atheros Communications, Inc.,  All Rights Reserved.
+ * Copyright (C) 2006 FON Technology, SL.
+ * Copyright (C) 2006 Imre Kaloz <[email protected]>
+ * Copyright (C) 2006 Felix Fietkau <[email protected]>
+ * Copyright (C) 2012 Alexandros C. Couloumbis <[email protected]>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/irq.h>
+
+#define DRIVER_NAME    "ar2315-gpio"
+
+#define AR2315_GPIO_DI                 0x0000
+#define AR2315_GPIO_DO                 0x0008
+#define AR2315_GPIO_DIR                        0x0010
+#define AR2315_GPIO_INT                        0x0018
+
+#define AR2315_GPIO_DIR_M(x)           (1 << (x))      /* mask for i/o */
+#define AR2315_GPIO_DIR_O(x)           (1 << (x))      /* output */
+#define AR2315_GPIO_DIR_I(x)           (0)             /* input */
+
+#define AR2315_GPIO_INT_NUM_M          0x3F            /* mask for GPIO num */
+#define AR2315_GPIO_INT_TRIG(x)                ((x) << 6)      /* interrupt 
trigger */
+#define AR2315_GPIO_INT_TRIG_M         (0x3 << 6)      /* mask for int trig */
+
+#define AR2315_GPIO_INT_TRIG_OFF       0       /* Triggerring off */
+#define AR2315_GPIO_INT_TRIG_LOW       1       /* Low Level Triggered */
+#define AR2315_GPIO_INT_TRIG_HIGH      2       /* High Level Triggered */
+#define AR2315_GPIO_INT_TRIG_EDGE      3       /* Edge Triggered */
+
+#define AR2315_GPIO_NUM                22
+
+static u32 ar2315_gpio_intmask;
+static u32 ar2315_gpio_intval;
+static unsigned ar2315_gpio_irq_base;
+static void __iomem *ar2315_mem;
+
+static inline u32 ar2315_gpio_reg_read(unsigned reg)
+{
+       return __raw_readl(ar2315_mem + reg);
+}
+
+static inline void ar2315_gpio_reg_write(unsigned reg, u32 val)
+{
+       __raw_writel(val, ar2315_mem + reg);
+}
+
+static inline void ar2315_gpio_reg_mask(unsigned reg, u32 mask, u32 val)
+{
+       ar2315_gpio_reg_write(reg, (ar2315_gpio_reg_read(reg) & ~mask) | val);
+}
+
+static void ar2315_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+       u32 pend;
+       int bit = -1;
+
+       /* only do one gpio interrupt at a time */
+       pend = ar2315_gpio_reg_read(AR2315_GPIO_DI);
+       pend ^= ar2315_gpio_intval;
+       pend &= ar2315_gpio_intmask;
+
+       if (pend) {
+               bit = fls(pend) - 1;
+               pend &= ~(1 << bit);
+               ar2315_gpio_intval ^= (1 << bit);
+       }
+
+       /* Enable interrupt with edge detection */
+       if ((ar2315_gpio_reg_read(AR2315_GPIO_DIR) & AR2315_GPIO_DIR_M(bit)) !=
+           AR2315_GPIO_DIR_I(bit))
+               return;
+
+       if (bit >= 0)
+               generic_handle_irq(ar2315_gpio_irq_base + bit);
+}
+
+static void ar2315_gpio_int_setup(unsigned gpio, int trig)
+{
+       u32 reg = ar2315_gpio_reg_read(AR2315_GPIO_INT);
+
+       reg &= ~(AR2315_GPIO_INT_NUM_M | AR2315_GPIO_INT_TRIG_M);
+       reg |= gpio | AR2315_GPIO_INT_TRIG(trig);
+       ar2315_gpio_reg_write(AR2315_GPIO_INT, reg);
+}
+
+static void ar2315_gpio_irq_unmask(struct irq_data *d)
+{
+       unsigned gpio = d->irq - ar2315_gpio_irq_base;
+       u32 dir = ar2315_gpio_reg_read(AR2315_GPIO_DIR);
+
+       /* Enable interrupt with edge detection */
+       if ((dir & AR2315_GPIO_DIR_M(gpio)) != AR2315_GPIO_DIR_I(gpio))
+               return;
+
+       ar2315_gpio_intmask |= (1 << gpio);
+       ar2315_gpio_int_setup(gpio, AR2315_GPIO_INT_TRIG_EDGE);
+}
+
+static void ar2315_gpio_irq_mask(struct irq_data *d)
+{
+       unsigned gpio = d->irq - ar2315_gpio_irq_base;
+
+       /* Disable interrupt */
+       ar2315_gpio_intmask &= ~(1 << gpio);
+       ar2315_gpio_int_setup(gpio, AR2315_GPIO_INT_TRIG_OFF);
+}
+
+static struct irq_chip ar2315_gpio_irq_chip = {
+       .name           = DRIVER_NAME,
+       .irq_unmask     = ar2315_gpio_irq_unmask,
+       .irq_mask       = ar2315_gpio_irq_mask,
+};
+
+static void ar2315_gpio_irq_init(unsigned irq)
+{
+       unsigned i;
+
+       ar2315_gpio_intval = ar2315_gpio_reg_read(AR2315_GPIO_DI);
+       for (i = 0; i < AR2315_GPIO_NUM; i++) {
+               unsigned _irq = ar2315_gpio_irq_base + i;
+
+               irq_set_chip_and_handler(_irq, &ar2315_gpio_irq_chip,
+                                        handle_level_irq);
+       }
+       irq_set_chained_handler(irq, ar2315_gpio_irq_handler);
+}
+
+static int ar2315_gpio_get_val(struct gpio_chip *chip, unsigned gpio)
+{
+       return (ar2315_gpio_reg_read(AR2315_GPIO_DI) >> gpio) & 1;
+}
+
+static void ar2315_gpio_set_val(struct gpio_chip *chip, unsigned gpio, int val)
+{
+       u32 reg = ar2315_gpio_reg_read(AR2315_GPIO_DO);
+
+       reg = val ? reg | (1 << gpio) : reg & ~(1 << gpio);
+       ar2315_gpio_reg_write(AR2315_GPIO_DO, reg);
+}
+
+static int ar2315_gpio_dir_in(struct gpio_chip *chip, unsigned gpio)
+{
+       ar2315_gpio_reg_mask(AR2315_GPIO_DIR, 1 << gpio, 0);
+       return 0;
+}
+
+static int ar2315_gpio_dir_out(struct gpio_chip *chip, unsigned gpio, int val)
+{
+       ar2315_gpio_reg_mask(AR2315_GPIO_DIR, 0, 1 << gpio);
+       ar2315_gpio_set_val(chip, gpio, val);
+       return 0;
+}
+
+static int ar2315_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
+{
+       return ar2315_gpio_irq_base + gpio;
+}
+
+static struct gpio_chip ar2315_gpio_chip = {
+       .label                  = DRIVER_NAME,
+       .direction_input        = ar2315_gpio_dir_in,
+       .direction_output       = ar2315_gpio_dir_out,
+       .set                    = ar2315_gpio_set_val,
+       .get                    = ar2315_gpio_get_val,
+       .to_irq                 = ar2315_gpio_to_irq,
+       .base                   = 0,
+       .ngpio                  = AR2315_GPIO_NUM,
+};
+
+static int ar2315_gpio_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct resource *res;
+       unsigned irq;
+       int ret;
+
+       if (ar2315_mem)
+               return -EBUSY;
+
+       res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, DRIVER_NAME);
+       if (!res) {
+               dev_err(dev, "not found IRQ number\n");
+               return -ENXIO;
+       }
+       irq = res->start;
+
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, DRIVER_NAME);
+       ar2315_mem = devm_ioremap_resource(dev, res);
+       if (IS_ERR(ar2315_mem))
+               return PTR_ERR(ar2315_mem);
+
+       ar2315_gpio_chip.dev = dev;
+       ret = gpiochip_add(&ar2315_gpio_chip);
+       if (ret) {
+               dev_err(dev, "failed to add gpiochip\n");
+               return ret;
+       }
+
+       ret = irq_alloc_descs(-1, 0, AR2315_GPIO_NUM, 0);
+       if (ret < 0) {
+               dev_err(dev, "failed to allocate IRQ numbers\n");
+               return ret;
+       }
+       ar2315_gpio_irq_base = ret;
+
+       ar2315_gpio_irq_init(irq);
+
+       return 0;
+}
+
+static struct platform_driver ar2315_gpio_driver = {
+       .probe = ar2315_gpio_probe,
+       .driver = {
+               .name = DRIVER_NAME,
+               .owner = THIS_MODULE,
+       }
+};
+
+static int __init ar2315_gpio_init(void)
+{
+       return platform_driver_register(&ar2315_gpio_driver);
+}
+subsys_initcall(ar2315_gpio_init);
-- 
1.8.5.5

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