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200 lines
5.1 KiB
200 lines
5.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Kontron PLD GPIO driver |
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* |
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* Copyright (c) 2010-2013 Kontron Europe GmbH |
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* Author: Michael Brunner <[email protected]> |
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*/ |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/bitops.h> |
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#include <linux/errno.h> |
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#include <linux/platform_device.h> |
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#include <linux/gpio/driver.h> |
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#include <linux/mfd/kempld.h> |
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#define KEMPLD_GPIO_MAX_NUM 16 |
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#define KEMPLD_GPIO_MASK(x) (BIT((x) % 8)) |
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#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8) |
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#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8) |
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#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46 |
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#define KEMPLD_GPIO_IEN 0x4A |
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struct kempld_gpio_data { |
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struct gpio_chip chip; |
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struct kempld_device_data *pld; |
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}; |
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/* |
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* Set or clear GPIO bit |
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* kempld_get_mutex must be called prior to calling this function. |
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*/ |
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static void kempld_gpio_bitop(struct kempld_device_data *pld, |
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u8 reg, u8 bit, u8 val) |
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{ |
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u8 status; |
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status = kempld_read8(pld, reg); |
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if (val) |
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status |= KEMPLD_GPIO_MASK(bit); |
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else |
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status &= ~KEMPLD_GPIO_MASK(bit); |
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kempld_write8(pld, reg, status); |
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} |
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static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit) |
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{ |
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u8 status; |
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kempld_get_mutex(pld); |
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status = kempld_read8(pld, reg); |
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kempld_release_mutex(pld); |
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return !!(status & KEMPLD_GPIO_MASK(bit)); |
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} |
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static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset) |
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{ |
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip); |
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struct kempld_device_data *pld = gpio->pld; |
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return !!kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset); |
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} |
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static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value) |
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{ |
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip); |
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struct kempld_device_data *pld = gpio->pld; |
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kempld_get_mutex(pld); |
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kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value); |
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kempld_release_mutex(pld); |
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} |
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static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset) |
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{ |
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip); |
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struct kempld_device_data *pld = gpio->pld; |
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kempld_get_mutex(pld); |
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kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0); |
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kempld_release_mutex(pld); |
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return 0; |
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} |
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static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset, |
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int value) |
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{ |
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip); |
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struct kempld_device_data *pld = gpio->pld; |
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kempld_get_mutex(pld); |
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kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value); |
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kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1); |
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kempld_release_mutex(pld); |
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return 0; |
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} |
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static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset) |
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{ |
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struct kempld_gpio_data *gpio = gpiochip_get_data(chip); |
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struct kempld_device_data *pld = gpio->pld; |
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if (kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset)) |
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return GPIO_LINE_DIRECTION_OUT; |
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return GPIO_LINE_DIRECTION_IN; |
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} |
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static int kempld_gpio_pincount(struct kempld_device_data *pld) |
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{ |
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u16 evt, evt_back; |
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kempld_get_mutex(pld); |
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/* Backup event register as it might be already initialized */ |
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evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE); |
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/* Clear event register */ |
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kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000); |
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/* Read back event register */ |
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evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE); |
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/* Restore event register */ |
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kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back); |
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kempld_release_mutex(pld); |
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return evt ? __ffs(evt) : 16; |
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} |
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static int kempld_gpio_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct kempld_device_data *pld = dev_get_drvdata(dev->parent); |
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struct kempld_platform_data *pdata = dev_get_platdata(pld->dev); |
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struct kempld_gpio_data *gpio; |
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struct gpio_chip *chip; |
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int ret; |
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if (pld->info.spec_major < 2) { |
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dev_err(dev, |
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"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n"); |
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return -ENODEV; |
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} |
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gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL); |
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if (!gpio) |
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return -ENOMEM; |
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gpio->pld = pld; |
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platform_set_drvdata(pdev, gpio); |
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chip = &gpio->chip; |
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chip->label = "gpio-kempld"; |
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chip->owner = THIS_MODULE; |
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chip->parent = dev; |
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chip->can_sleep = true; |
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if (pdata && pdata->gpio_base) |
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chip->base = pdata->gpio_base; |
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else |
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chip->base = -1; |
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chip->direction_input = kempld_gpio_direction_input; |
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chip->direction_output = kempld_gpio_direction_output; |
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chip->get_direction = kempld_gpio_get_direction; |
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chip->get = kempld_gpio_get; |
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chip->set = kempld_gpio_set; |
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chip->ngpio = kempld_gpio_pincount(pld); |
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if (chip->ngpio == 0) { |
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dev_err(dev, "No GPIO pins detected\n"); |
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return -ENODEV; |
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} |
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ret = devm_gpiochip_add_data(dev, chip, gpio); |
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if (ret) { |
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dev_err(dev, "Could not register GPIO chip\n"); |
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return ret; |
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} |
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dev_info(dev, "GPIO functionality initialized with %d pins\n", |
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chip->ngpio); |
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return 0; |
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} |
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static struct platform_driver kempld_gpio_driver = { |
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.driver = { |
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.name = "kempld-gpio", |
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}, |
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.probe = kempld_gpio_probe, |
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}; |
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module_platform_driver(kempld_gpio_driver); |
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MODULE_DESCRIPTION("KEM PLD GPIO Driver"); |
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MODULE_AUTHOR("Michael Brunner <[email protected]>"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:kempld-gpio");
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