[PATCH v9 4/4] gpio: add support for the Diolan DLN-2 USB GPIO driver

Octavian Purdila
2014-10-27T16:31:44Z

From: Daniel Baluta <daniel.baluta@intel.com>

This patch adds GPIO and IRQ support for the Diolan DLN-2 GPIO module.

Information about the USB protocol interface can be found in the
Programmer's Reference Manual [1], see section 2.9 for the GPIO
module commands and responses.

[1] https://www.diolan.com/downloads/dln-api-manual.pdf

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
drivers/gpio/Kconfig | 12 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-dln2.c | 553 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 566 insertions(+)
create mode 100644 drivers/gpio/gpio-dln2.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9de1515..44ec206 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -897,4 +897,16 @@ config GPIO_VIPERBOARD
River Tech's viperboard.h for detailed meaning
of the module parameters.

+config GPIO_DLN2
+ tristate "Diolan DLN2 GPIO support"
+ depends on MFD_DLN2
+ select GPIOLIB_IRQCHIP
+
+ help
+ Select this option to enable GPIO driver for the Diolan DLN2
+ board.
+
+ This driver can also be built as a module. If so, the module
+ will be called gpio-dln2.
+
endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d024e3..eaa97a0 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_GPIO_CRYSTAL_COVE) += gpio-crystalcove.o
obj-$(CONFIG_GPIO_DA9052) += gpio-da9052.o
obj-$(CONFIG_GPIO_DA9055) += gpio-da9055.o
obj-$(CONFIG_GPIO_DAVINCI) += gpio-davinci.o
+obj-$(CONFIG_GPIO_DLN2) += gpio-dln2.o
obj-$(CONFIG_GPIO_DWAPB) += gpio-dwapb.o
obj-$(CONFIG_GPIO_EM) += gpio-em.o
obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o
diff --git a/drivers/gpio/gpio-dln2.c b/drivers/gpio/gpio-dln2.c
new file mode 100644
index 0000000..0e31d73
--- /dev/null
+++ b/drivers/gpio/gpio-dln2.c
@@ -0,0 +1,553 @@
+/*
+ * Driver for the Diolan DLN-2 USB-GPIO adapter
+ *
+ * Copyright (c) 2014 Intel Corporation
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/dln2.h>
+
+#define DLN2_GPIO_ID 0x01
+
+#define DLN2_GPIO_GET_PIN_COUNT DLN2_CMD(0x01, DLN2_GPIO_ID)
+#define DLN2_GPIO_SET_DEBOUNCE DLN2_CMD(0x04, DLN2_GPIO_ID)
+#define DLN2_GPIO_GET_DEBOUNCE DLN2_CMD(0x05, DLN2_GPIO_ID)
+#define DLN2_GPIO_PORT_GET_VAL DLN2_CMD(0x06, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_VAL DLN2_CMD(0x0B, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_OUT_VAL DLN2_CMD(0x0C, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_OUT_VAL DLN2_CMD(0x0D, DLN2_GPIO_ID)
+#define DLN2_GPIO_CONDITION_MET_EV DLN2_CMD(0x0F, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_ENABLE DLN2_CMD(0x10, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_DISABLE DLN2_CMD(0x11, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_DIRECTION DLN2_CMD(0x13, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_DIRECTION DLN2_CMD(0x14, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_SET_EVENT_CFG DLN2_CMD(0x1E, DLN2_GPIO_ID)
+#define DLN2_GPIO_PIN_GET_EVENT_CFG DLN2_CMD(0x1F, DLN2_GPIO_ID)
+
+#define DLN2_GPIO_EVENT_NONE 0
+#define DLN2_GPIO_EVENT_CHANGE 1
+#define DLN2_GPIO_EVENT_LVL_HIGH 2
+#define DLN2_GPIO_EVENT_LVL_LOW 3
+#define DLN2_GPIO_EVENT_CHANGE_RISING 0x11
+#define DLN2_GPIO_EVENT_CHANGE_FALLING 0x21
+#define DLN2_GPIO_EVENT_MASK 0x0F
+
+#define DLN2_GPIO_MAX_PINS 32
+
+struct dln2_irq_work {
+ struct work_struct work;
+ struct dln2_gpio *dln2;
+ int pin;
+ int type;
+};
+
+struct dln2_gpio {
+ struct platform_device *pdev;
+ struct gpio_chip gpio;
+
+ /*
+ * Cache pin direction to save us one transfer, since the hardware has
+ * separate commands to read the in and out values.
+ */
+ DECLARE_BITMAP(output_enabled, DLN2_GPIO_MAX_PINS);
+
+ DECLARE_BITMAP(irqs_masked, DLN2_GPIO_MAX_PINS);
+ DECLARE_BITMAP(irqs_enabled, DLN2_GPIO_MAX_PINS);
+ DECLARE_BITMAP(irqs_pending, DLN2_GPIO_MAX_PINS);
+ struct dln2_irq_work *irq_work;
+};
+
+struct dln2_gpio_pin {
+ __le16 pin;
+};
+
+struct dln2_gpio_pin_val {
+ __le16 pin __packed;
+ u8 value;
+};
+
+static int dln2_gpio_get_pin_count(struct platform_device *pdev)
+{
+ int ret;
+ __le16 count;
+ int len = sizeof(count);
+
+ ret = dln2_transfer_rx(pdev, DLN2_GPIO_GET_PIN_COUNT, &count, &len);
+ if (ret < 0)
+ return ret;
+ if (len < sizeof(count))
+ return -EPROTO;
+
+ return le16_to_cpu(count);
+}
+
+static int dln2_gpio_pin_cmd(struct dln2_gpio *dln2, int cmd, unsigned pin)
+{
+ struct dln2_gpio_pin req = {
+ .pin = cpu_to_le16(pin),
+ };
+
+ return dln2_transfer_tx(dln2->pdev, cmd, &req, sizeof(req));
+}
+
+static int dln2_gpio_pin_val(struct dln2_gpio *dln2, int cmd, unsigned int pin)
+{
+ int ret;
+ struct dln2_gpio_pin req = {
+ .pin = cpu_to_le16(pin),
+ };
+ struct dln2_gpio_pin_val rsp;
+ int len = sizeof(rsp);
+
+ ret = dln2_transfer(dln2->pdev, cmd, &req, sizeof(req), &rsp, &len);
+ if (ret < 0)
+ return ret;
+ if (len < sizeof(rsp) || req.pin != rsp.pin)
+ return -EPROTO;
+
+ return rsp.value;
+}
+
+static int dln2_gpio_pin_get_in_val(struct dln2_gpio *dln2, unsigned int pin)
+{
+ int ret;
+
+ ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_VAL, pin);
+ if (ret < 0)
+ return ret;
+ return !!ret;
+}
+
+static int dln2_gpio_pin_get_out_val(struct dln2_gpio *dln2, unsigned int pin)
+{
+ int ret;
+
+ ret = dln2_gpio_pin_val(dln2, DLN2_GPIO_PIN_GET_OUT_VAL, pin);
+ if (ret < 0)
+ return ret;
+ return !!ret;
+}
+
+static void dln2_gpio_pin_set_out_val(struct dln2_gpio *dln2,
+ unsigned int pin, int value)
+{
+ struct dln2_gpio_pin_val req = {
+ .pin = cpu_to_le16(pin),
+ .value = cpu_to_le16(value),
+ };
+
+ dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_OUT_VAL, &req,
+ sizeof(req));
+}
+
+#define DLN2_GPIO_DIRECTION_IN 0
+#define DLN2_GPIO_DIRECTION_OUT 1
+
+static int dln2_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+ struct dln2_gpio_pin req = {
+ .pin = cpu_to_le16(offset),
+ };
+ struct dln2_gpio_pin_val rsp;
+ int len = sizeof(rsp);
+ int ret;
+
+ ret = dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_ENABLE, offset);
+ if (ret < 0)
+ return ret;
+
+ /* cache the pin direction */
+ ret = dln2_transfer(dln2->pdev, DLN2_GPIO_PIN_GET_DIRECTION,
+ &req, sizeof(req), &rsp, &len);
+ if (ret < 0)
+ return ret;
+ if (len < sizeof(rsp) || req.pin != rsp.pin) {
+ ret = -EPROTO;
+ goto out_disable;
+ }
+
+ switch (rsp.value) {
+ case DLN2_GPIO_DIRECTION_IN:
+ clear_bit(offset, dln2->output_enabled);
+ return 0;
+ case DLN2_GPIO_DIRECTION_OUT:
+ set_bit(offset, dln2->output_enabled);
+ return 0;
+ default:
+ ret = -EPROTO;
+ goto out_disable;
+ }
+
+out_disable:
+ dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
+ return ret;
+}
+
+static void dln2_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+ dln2_gpio_pin_cmd(dln2, DLN2_GPIO_PIN_DISABLE, offset);
+}
+
+static int dln2_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+ if (test_bit(offset, dln2->output_enabled))
+ return GPIOF_DIR_OUT;
+
+ return GPIOF_DIR_IN;
+}
+
+static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+ int dir;
+
+ dir = dln2_gpio_get_direction(chip, offset);
+ if (dir < 0)
+ return dir;
+
+ if (dir == GPIOF_DIR_IN)
+ return dln2_gpio_pin_get_in_val(dln2, offset);
+
+ return dln2_gpio_pin_get_out_val(dln2, offset);
+}
+
+static void dln2_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+
+ dln2_gpio_pin_set_out_val(dln2, offset, value);
+}
+
+static int dln2_gpio_set_direction(struct gpio_chip *chip, unsigned offset,
+ unsigned dir)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+ struct dln2_gpio_pin_val req = {
+ .pin = cpu_to_le16(offset),
+ .value = cpu_to_le16(dir),
+ };
+ int ret;
+
+ ret = dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_DIRECTION,
+ &req, sizeof(req));
+ if (ret < 0)
+ return ret;
+
+ if (dir == DLN2_GPIO_DIRECTION_OUT)
+ set_bit(offset, dln2->output_enabled);
+ else
+ clear_bit(offset, dln2->output_enabled);
+
+ return ret;
+}
+
+static int dln2_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+ return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_IN);
+}
+
+static int dln2_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+ int value)
+{
+ return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT);
+}
+
+static int dln2_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
+ unsigned debounce)
+{
+ struct dln2_gpio *dln2 = container_of(chip, struct dln2_gpio, gpio);
+ __le32 duration = cpu_to_le32(debounce);
+
+ return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_SET_DEBOUNCE,
+ &duration, sizeof(duration));
+}
+
+static int dln2_gpio_set_event_cfg(struct dln2_gpio *dln2, unsigned pin,
+ unsigned type, unsigned period)
+{
+ struct {
+ __le16 pin;
+ u8 type;
+ __le16 period;
+ } __packed req = {
+ .pin = cpu_to_le16(pin),
+ .type = type,
+ .period = cpu_to_le16(period),
+ };
+
+ return dln2_transfer_tx(dln2->pdev, DLN2_GPIO_PIN_SET_EVENT_CFG,
+ &req, sizeof(req));
+}
+
+static void dln2_irq_work(struct work_struct *w)
+{
+ struct dln2_irq_work *iw = container_of(w, struct dln2_irq_work, work);
+ struct dln2_gpio *dln2 = iw->dln2;
+ u8 type = iw->type & DLN2_GPIO_EVENT_MASK;
+
+ if (test_bit(iw->pin, dln2->irqs_enabled))
+ dln2_gpio_set_event_cfg(dln2, iw->pin, type, 0);
+ else
+ dln2_gpio_set_event_cfg(dln2, iw->pin, DLN2_GPIO_EVENT_NONE, 0);
+}
+
+static void dln2_irq_enable(struct irq_data *irqd)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+ int pin = irqd_to_hwirq(irqd);
+
+ set_bit(pin, dln2->irqs_enabled);
+ schedule_work(&dln2->irq_work[pin].work);
+}
+
+static void dln2_irq_disable(struct irq_data *irqd)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+ int pin = irqd_to_hwirq(irqd);
+
+ clear_bit(pin, dln2->irqs_enabled);
+ schedule_work(&dln2->irq_work[pin].work);
+}
+
+static void dln2_irq_mask(struct irq_data *irqd)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+ int pin = irqd_to_hwirq(irqd);
+
+ set_bit(pin, dln2->irqs_masked);
+}
+
+static void dln2_irq_unmask(struct irq_data *irqd)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+ struct device *dev = dln2->gpio.dev;
+ int pin = irqd_to_hwirq(irqd);
+
+ if (test_and_clear_bit(pin, dln2->irqs_pending)) {
+ int irq;
+
+ irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
+ if (!irq) {
+ dev_err(dev, "pin %d not mapped to IRQ\n", pin);
+ return;
+ }
+
+ generic_handle_irq(irq);
+ }
+}
+
+static int dln2_irq_set_type(struct irq_data *irqd, unsigned type)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
+ struct dln2_gpio *dln2 = container_of(gc, struct dln2_gpio, gpio);
+ int pin = irqd_to_hwirq(irqd);
+
+ switch (type) {
+ case IRQ_TYPE_LEVEL_HIGH:
+ dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_HIGH;
+ break;
+ case IRQ_TYPE_LEVEL_LOW:
+ dln2->irq_work[pin].type = DLN2_GPIO_EVENT_LVL_LOW;
+ break;
+ case IRQ_TYPE_EDGE_BOTH:
+ dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE;
+ break;
+ case IRQ_TYPE_EDGE_RISING:
+ dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_RISING;
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ dln2->irq_work[pin].type = DLN2_GPIO_EVENT_CHANGE_FALLING;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static struct irq_chip dln2_gpio_irqchip = {
+ .name = "dln2-irq",
+ .irq_enable = dln2_irq_enable,
+ .irq_disable = dln2_irq_disable,
+ .irq_mask = dln2_irq_mask,
+ .irq_unmask = dln2_irq_unmask,
+ .irq_set_type = dln2_irq_set_type,
+};
+
+static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
+ const void *data, int len)
+{
+ int pin, irq;
+ const struct {
+ __le16 count;
+ __u8 type;
+ __le16 pin;
+ __u8 value;
+ } __packed *event = data;
+ struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
+
+ if (len < sizeof(*event)) {
+ dev_err(dln2->gpio.dev, "short event message\n");
+ return;
+ }
+
+ pin = le16_to_cpu(event->pin);
+ if (pin >= dln2->gpio.ngpio) {
+ dev_err(dln2->gpio.dev, "out of bounds pin %d\n", pin);
+ return;
+ }
+
+ irq = irq_find_mapping(dln2->gpio.irqdomain, pin);
+ if (!irq) {
+ dev_err(dln2->gpio.dev, "pin %d not mapped to IRQ\n", pin);
+ return;
+ }
+
+ if (!test_bit(pin, dln2->irqs_enabled))
+ return;
+ if (test_bit(pin, dln2->irqs_masked)) {
+ set_bit(pin, dln2->irqs_pending);
+ return;
+ }
+
+ switch (dln2->irq_work[pin].type) {
+ case DLN2_GPIO_EVENT_CHANGE_RISING:
+ if (event->value)
+ generic_handle_irq(irq);
+ break;
+ case DLN2_GPIO_EVENT_CHANGE_FALLING:
+ if (!event->value)
+ generic_handle_irq(irq);
+ break;
+ default:
+ generic_handle_irq(irq);
+ }
+}
+
+static int dln2_gpio_probe(struct platform_device *pdev)
+{
+ struct dln2_gpio *dln2;
+ struct device *dev = &pdev->dev;
+ int pins;
+ int i, ret;
+
+ pins = dln2_gpio_get_pin_count(pdev);
+ if (pins < 0) {
+ dev_err(dev, "failed to get pin count: %d\n", pins);
+ return pins;
+ }
+ if (pins > DLN2_GPIO_MAX_PINS) {
+ pins = DLN2_GPIO_MAX_PINS;
+ dev_warn(dev, "clamping pins to %d\n", DLN2_GPIO_MAX_PINS);
+ }
+
+ dln2 = devm_kzalloc(&pdev->dev, sizeof(*dln2), GFP_KERNEL);
+ if (!dln2)
+ return -ENOMEM;
+
+ dln2->irq_work = devm_kcalloc(&pdev->dev, pins,
+ sizeof(struct dln2_irq_work), GFP_KERNEL);
+ if (!dln2->irq_work)
+ return -ENOMEM;
+ for (i = 0; i < pins; i++) {
+ INIT_WORK(&dln2->irq_work[i].work, dln2_irq_work);
+ dln2->irq_work[i].pin = i;
+ dln2->irq_work[i].dln2 = dln2;
+ }
+
+ dln2->pdev = pdev;
+
+ dln2->gpio.label = "dln2";
+ dln2->gpio.dev = dev;
+ dln2->gpio.owner = THIS_MODULE;
+ dln2->gpio.base = -1;
+ dln2->gpio.ngpio = pins;
+ dln2->gpio.exported = true;
+ dln2->gpio.can_sleep = true;
+ dln2->gpio.irq_not_threaded = true;
+ dln2->gpio.set = dln2_gpio_set;
+ dln2->gpio.get = dln2_gpio_get;
+ dln2->gpio.request = dln2_gpio_request;
+ dln2->gpio.free = dln2_gpio_free;
+ dln2->gpio.get_direction = dln2_gpio_get_direction;
+ dln2->gpio.direction_input = dln2_gpio_direction_input;
+ dln2->gpio.direction_output = dln2_gpio_direction_output;
+ dln2->gpio.set_debounce = dln2_gpio_set_debounce;
+
+ platform_set_drvdata(pdev, dln2);
+
+ ret = gpiochip_add(&dln2->gpio);
+ if (ret < 0) {
+ dev_err(dev, "failed to add gpio chip: %d\n", ret);
+ goto out;
+ }
+
+ ret = gpiochip_irqchip_add(&dln2->gpio, &dln2_gpio_irqchip, 0,
+ handle_simple_irq, IRQ_TYPE_NONE);
+ if (ret < 0) {
+ dev_err(dev, "failed to add irq chip: %d\n", ret);
+ goto out_gpiochip_remove;
+ }
+
+ ret = dln2_register_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV,
+ dln2_gpio_event);
+ if (ret) {
+ dev_err(dev, "failed to register event cb: %d\n", ret);
+ goto out_gpiochip_remove;
+ }
+
+ return 0;
+
+out_gpiochip_remove:
+ gpiochip_remove(&dln2->gpio);
+out:
+ return ret;
+}
+
+static int dln2_gpio_remove(struct platform_device *pdev)
+{
+ struct dln2_gpio *dln2 = platform_get_drvdata(pdev);
+ int i;
+
+ dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV);
+ for (i = 0; i < dln2->gpio.ngpio; i++)
+ flush_work(&dln2->irq_work[i].work);
+ gpiochip_remove(&dln2->gpio);
+
+ return 0;
+}
+
+static struct platform_driver dln2_gpio_driver = {
+ .driver.name = "dln2-gpio",
+ .probe = dln2_gpio_probe,
+ .remove = dln2_gpio_remove,
+};
+
+module_platform_driver(dln2_gpio_driver);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com");
+MODULE_DESCRIPTION("Driver for the Diolan DLN2 GPIO interface");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dln2-gpio");
--
1.9.1