Adds support for USB-GPIO interface of Cypress Semiconductor
CYUSBS234 USB-Serial Bridge controller.

The GPIO get/set can be done through vendor command on control endpoint.

Details about the device can be found at:
http://www.cypress.com/?rID=84126

Signed-off-by: Muthu Mani <m...@cypress.com>
Signed-off-by: Rajaram Regupathy <r...@cypress.com>
---
 drivers/gpio/Kconfig          |  13 +++
 drivers/gpio/Makefile         |   1 +
 drivers/gpio/gpio-cyusbs23x.c | 182 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 196 insertions(+)
 create mode 100644 drivers/gpio/gpio-cyusbs23x.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9de1515..932e07c 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -886,6 +886,19 @@ config GPIO_BCM_KONA
 
 comment "USB GPIO expanders:"
 
+config GPIO_CYUSBS23X
+       tristate "CYUSBS23x GPIO support"
+       depends on MFD_CYUSBS23X && USB
+       help
+         Say yes here to access the GPIO signals of Cypress
+         Semiconductor CYUSBS23x USB Serial Bridge Controller.
+
+         This driver enables the GPIO interface of CYUSBS23x USB Serial
+         Bridge controller.
+
+         This driver can also be built as a module. If so, the module will be
+         called gpio-cyusbs23x.
+
 config GPIO_VIPERBOARD
        tristate "Viperboard GPIO a & b support"
        depends on MFD_VIPERBOARD && USB
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d024e3..3ad89f1 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_GPIO_BT8XX)      += gpio-bt8xx.o
 obj-$(CONFIG_GPIO_CLPS711X)    += gpio-clps711x.o
 obj-$(CONFIG_GPIO_CS5535)      += gpio-cs5535.o
 obj-$(CONFIG_GPIO_CRYSTAL_COVE)        += gpio-crystalcove.o
+obj-$(CONFIG_GPIO_CYUSBS23X)   += gpio-cyusbs23x.o
 obj-$(CONFIG_GPIO_DA9052)      += gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)      += gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)     += gpio-davinci.o
diff --git a/drivers/gpio/gpio-cyusbs23x.c b/drivers/gpio/gpio-cyusbs23x.c
new file mode 100644
index 0000000..ad83b00
--- /dev/null
+++ b/drivers/gpio/gpio-cyusbs23x.c
@@ -0,0 +1,182 @@
+/*
+ * GPIO subdriver for Cypress CYUSBS234 USB-Serial Bridge controller.
+ * Details about the device can be found at:
+ *    http://www.cypress.com/?rID=84126
+ * All GPIOs are exposed for get operation and only unused GPIOs can be set.
+ *
+ * Copyright (c) 2014 Cypress Semiconductor Corporation.
+ *
+ * Author:
+ *   Muthu Mani <m...@cypress.com>
+ *
+ * Additional contributors include:
+ *   Rajaram Regupathy <r...@cypress.com>
+ *
+ * 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/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#include <linux/usb.h>
+#include <linux/gpio.h>
+
+#include <linux/mfd/cyusbs23x.h>
+
+#define CY_GPIO_GET_LEN                (2)
+
+struct cyusbs_gpio {
+       struct gpio_chip gpio;
+       struct cyusbs23x *cyusbs;
+};
+
+static int cy_gpio_get(struct gpio_chip *chip,
+                       unsigned offset)
+{
+       int ret;
+       char *buf;
+       u16 wIndex, wValue;
+       struct cyusbs_gpio *gpio =
+                               container_of(chip, struct cyusbs_gpio, gpio);
+       struct cyusbs23x *cyusbs = gpio->cyusbs;
+
+       dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
+               offset);
+       wValue = offset;
+       wIndex = 0;
+       buf = kmalloc(CY_GPIO_GET_LEN, GFP_KERNEL);
+
+       mutex_lock(&cyusbs->lock);
+       ret = usb_control_msg(cyusbs->usb_dev,
+                       usb_rcvctrlpipe(cyusbs->usb_dev, 0),
+                       CY_GPIO_GET_VALUE_CMD,
+                       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+                       wValue, wIndex, buf, CY_GPIO_GET_LEN, 2000);
+       mutex_unlock(&cyusbs->lock);
+
+       dev_dbg(&cyusbs->usb_intf->dev, "%s: %d %02x %02x\n", __func__,
+               ret, buf[0], buf[1]);
+
+       if (ret == CY_GPIO_GET_LEN) {
+               if (buf[0] == 0)
+                       ret = buf[1];
+               else
+                       ret = -EINVAL;
+       } else {
+               ret = -EREMOTEIO;
+       }
+
+       kfree(buf);
+       return ret;
+}
+
+static void cy_gpio_set(struct gpio_chip *chip,
+                       unsigned offset, int value)
+{
+       int ret;
+       u16 wIndex, wValue;
+       struct cyusbs_gpio *gpio =
+                       container_of(chip, struct cyusbs_gpio, gpio);
+       struct cyusbs23x *cyusbs = gpio->cyusbs;
+
+       dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
+               offset);
+       wValue = offset;
+       wIndex = value;
+
+       mutex_lock(&cyusbs->lock);
+       ret = usb_control_msg(cyusbs->usb_dev,
+                       usb_sndctrlpipe(cyusbs->usb_dev, 0),
+                       CY_GPIO_SET_VALUE_CMD,
+                       USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+                       wValue, wIndex, NULL, 0, 2000);
+       mutex_unlock(&cyusbs->lock);
+
+       if (ret < 0)
+               dev_err(&cyusbs->usb_intf->dev, "error setting gpio:%d\n", ret);
+}
+
+static int cy_gpio_direction_input(struct gpio_chip *chip,
+                                       unsigned offset)
+{
+       return 0;
+}
+
+static int cy_gpio_direction_output(struct gpio_chip *chip,
+                                       unsigned offset, int value)
+{
+       return 0;
+}
+
+static int cyusbs23x_gpio_probe(struct platform_device *pdev)
+{
+       struct cyusbs23x *cyusbs;
+       struct cyusbs_gpio *cy_gpio;
+       int ret = 0;
+
+       dev_dbg(&pdev->dev, "%s\n", __func__);
+
+       cyusbs = dev_get_drvdata(pdev->dev.parent);
+
+       cy_gpio = devm_kzalloc(&pdev->dev, sizeof(*cy_gpio), GFP_KERNEL);
+       if (cy_gpio == NULL)
+               return -ENOMEM;
+
+       cy_gpio->cyusbs = cyusbs;
+       /* registering gpio */
+       cy_gpio->gpio.label = dev_name(&pdev->dev);
+       cy_gpio->gpio.dev = &pdev->dev;
+       cy_gpio->gpio.owner = THIS_MODULE;
+       cy_gpio->gpio.base = -1;
+       cy_gpio->gpio.ngpio = 12; /* total GPIOs */
+       cy_gpio->gpio.can_sleep = true;
+       cy_gpio->gpio.set = cy_gpio_set;
+       cy_gpio->gpio.get = cy_gpio_get;
+       cy_gpio->gpio.direction_input = cy_gpio_direction_input;
+       cy_gpio->gpio.direction_output = cy_gpio_direction_output;
+       ret = gpiochip_add(&cy_gpio->gpio);
+       if (ret < 0) {
+               dev_err(cy_gpio->gpio.dev, "could not add gpio");
+               goto error;
+       }
+
+       platform_set_drvdata(pdev, cy_gpio);
+
+       dev_dbg(&pdev->dev, "added GPIO\n");
+       return ret;
+
+error:
+       dev_dbg(&pdev->dev, "error occured %d\n", ret);
+       return ret;
+}
+
+static int cyusbs23x_gpio_remove(struct platform_device *pdev)
+{
+       struct cyusbs_gpio *cy_gpio = platform_get_drvdata(pdev);
+
+       dev_dbg(&pdev->dev, "%s\n", __func__);
+       gpiochip_remove(&cy_gpio->gpio);
+       return 0;
+}
+
+static struct platform_driver cyusbs23x_gpio_driver = {
+       .driver.name    = "cyusbs23x-gpio",
+       .driver.owner   = THIS_MODULE,
+       .probe          = cyusbs23x_gpio_probe,
+       .remove         = cyusbs23x_gpio_remove,
+};
+
+module_platform_driver(cyusbs23x_gpio_driver);
+
+MODULE_AUTHOR("Rajaram Regupathy <r...@cypress.com>");
+MODULE_AUTHOR("Muthu Mani <m...@cypress.com>");
+MODULE_DESCRIPTION("GPIO driver for CYUSBS23x");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:cyusbs23x-gpio");
-- 
1.8.3.2

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