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linux/drivers/gpio/gpio-dln2.c
Uwe Kleine-König 6a277ca75e gpio: dln2: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2023-10-02 08:54:31 +02:00

524 lines
13 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for the Diolan DLN-2 USB-GPIO adapter
*
* Copyright (c) 2014 Intel Corporation
*/
#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/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_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);
/* active IRQs - not synced to hardware */
DECLARE_BITMAP(unmasked_irqs, DLN2_GPIO_MAX_PINS);
/* active IRQS - synced to hardware */
DECLARE_BITMAP(enabled_irqs, DLN2_GPIO_MAX_PINS);
int irq_type[DLN2_GPIO_MAX_PINS];
struct mutex irq_lock;
};
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 int 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 = value,
};
return 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 = gpiochip_get_data(chip);
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 = gpiochip_get_data(chip);
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 = gpiochip_get_data(chip);
if (test_bit(offset, dln2->output_enabled))
return GPIO_LINE_DIRECTION_OUT;
return GPIO_LINE_DIRECTION_IN;
}
static int dln2_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
struct dln2_gpio *dln2 = gpiochip_get_data(chip);
int dir;
dir = dln2_gpio_get_direction(chip, offset);
if (dir < 0)
return dir;
if (dir == GPIO_LINE_DIRECTION_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 = gpiochip_get_data(chip);
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 = gpiochip_get_data(chip);
struct dln2_gpio_pin_val req = {
.pin = cpu_to_le16(offset),
.value = 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)
{
struct dln2_gpio *dln2 = gpiochip_get_data(chip);
int ret;
ret = dln2_gpio_pin_set_out_val(dln2, offset, value);
if (ret < 0)
return ret;
return dln2_gpio_set_direction(chip, offset, DLN2_GPIO_DIRECTION_OUT);
}
static int dln2_gpio_set_config(struct gpio_chip *chip, unsigned offset,
unsigned long config)
{
struct dln2_gpio *dln2 = gpiochip_get_data(chip);
__le32 duration;
if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
return -ENOTSUPP;
duration = cpu_to_le32(pinconf_to_config_argument(config));
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_unmask(struct irq_data *irqd)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
struct dln2_gpio *dln2 = gpiochip_get_data(gc);
int pin = irqd_to_hwirq(irqd);
gpiochip_enable_irq(gc, pin);
set_bit(pin, dln2->unmasked_irqs);
}
static void dln2_irq_mask(struct irq_data *irqd)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
struct dln2_gpio *dln2 = gpiochip_get_data(gc);
int pin = irqd_to_hwirq(irqd);
clear_bit(pin, dln2->unmasked_irqs);
gpiochip_disable_irq(gc, pin);
}
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 = gpiochip_get_data(gc);
int pin = irqd_to_hwirq(irqd);
switch (type) {
case IRQ_TYPE_LEVEL_HIGH:
dln2->irq_type[pin] = DLN2_GPIO_EVENT_LVL_HIGH;
break;
case IRQ_TYPE_LEVEL_LOW:
dln2->irq_type[pin] = DLN2_GPIO_EVENT_LVL_LOW;
break;
case IRQ_TYPE_EDGE_BOTH:
dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE;
break;
case IRQ_TYPE_EDGE_RISING:
dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE_RISING;
break;
case IRQ_TYPE_EDGE_FALLING:
dln2->irq_type[pin] = DLN2_GPIO_EVENT_CHANGE_FALLING;
break;
default:
return -EINVAL;
}
return 0;
}
static void dln2_irq_bus_lock(struct irq_data *irqd)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
struct dln2_gpio *dln2 = gpiochip_get_data(gc);
mutex_lock(&dln2->irq_lock);
}
static void dln2_irq_bus_unlock(struct irq_data *irqd)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(irqd);
struct dln2_gpio *dln2 = gpiochip_get_data(gc);
int pin = irqd_to_hwirq(irqd);
int enabled, unmasked;
unsigned type;
int ret;
enabled = test_bit(pin, dln2->enabled_irqs);
unmasked = test_bit(pin, dln2->unmasked_irqs);
if (enabled != unmasked) {
if (unmasked) {
type = dln2->irq_type[pin] & DLN2_GPIO_EVENT_MASK;
set_bit(pin, dln2->enabled_irqs);
} else {
type = DLN2_GPIO_EVENT_NONE;
clear_bit(pin, dln2->enabled_irqs);
}
ret = dln2_gpio_set_event_cfg(dln2, pin, type, 0);
if (ret)
dev_err(dln2->gpio.parent, "failed to set event\n");
}
mutex_unlock(&dln2->irq_lock);
}
static const struct irq_chip dln2_irqchip = {
.name = "dln2-irq",
.irq_mask = dln2_irq_mask,
.irq_unmask = dln2_irq_unmask,
.irq_set_type = dln2_irq_set_type,
.irq_bus_lock = dln2_irq_bus_lock,
.irq_bus_sync_unlock = dln2_irq_bus_unlock,
.flags = IRQCHIP_IMMUTABLE,
GPIOCHIP_IRQ_RESOURCE_HELPERS,
};
static void dln2_gpio_event(struct platform_device *pdev, u16 echo,
const void *data, int len)
{
int pin, ret;
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.parent, "short event message\n");
return;
}
pin = le16_to_cpu(event->pin);
if (pin >= dln2->gpio.ngpio) {
dev_err(dln2->gpio.parent, "out of bounds pin %d\n", pin);
return;
}
switch (dln2->irq_type[pin]) {
case DLN2_GPIO_EVENT_CHANGE_RISING:
if (!event->value)
return;
break;
case DLN2_GPIO_EVENT_CHANGE_FALLING:
if (event->value)
return;
break;
}
ret = generic_handle_domain_irq(dln2->gpio.irq.domain, pin);
if (unlikely(ret))
dev_err(dln2->gpio.parent, "pin %d not mapped to IRQ\n", pin);
}
static int dln2_gpio_probe(struct platform_device *pdev)
{
struct dln2_gpio *dln2;
struct device *dev = &pdev->dev;
struct gpio_irq_chip *girq;
int pins;
int 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;
mutex_init(&dln2->irq_lock);
dln2->pdev = pdev;
dln2->gpio.label = "dln2";
dln2->gpio.parent = dev;
dln2->gpio.owner = THIS_MODULE;
dln2->gpio.base = -1;
dln2->gpio.ngpio = pins;
dln2->gpio.can_sleep = 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_config = dln2_gpio_set_config;
girq = &dln2->gpio.irq;
gpio_irq_chip_set_chip(girq, &dln2_irqchip);
/* The event comes from the outside so no parent handler */
girq->parent_handler = NULL;
girq->num_parents = 0;
girq->parents = NULL;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_simple_irq;
platform_set_drvdata(pdev, dln2);
ret = devm_gpiochip_add_data(dev, &dln2->gpio, dln2);
if (ret < 0) {
dev_err(dev, "failed to add gpio chip: %d\n", ret);
return ret;
}
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);
return ret;
}
return 0;
}
static void dln2_gpio_remove(struct platform_device *pdev)
{
dln2_unregister_event_cb(pdev, DLN2_GPIO_CONDITION_MET_EV);
}
static struct platform_driver dln2_gpio_driver = {
.driver.name = "dln2-gpio",
.probe = dln2_gpio_probe,
.remove_new = 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");
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