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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Kontron PLD GPIO driver4 *5 * Copyright (c) 2010-2013 Kontron Europe GmbH6 * Author: Michael Brunner <michael.brunner@kontron.com>7 */8 9#include <linux/init.h>10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/bitops.h>13#include <linux/errno.h>14#include <linux/platform_device.h>15#include <linux/gpio/driver.h>16#include <linux/mfd/kempld.h>17 18#define KEMPLD_GPIO_MAX_NUM 1619#define KEMPLD_GPIO_MASK(x) (BIT((x) % 8))20#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)21#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)22#define KEMPLD_GPIO_EVT_LVL_EDGE 0x4623#define KEMPLD_GPIO_IEN 0x4A24 25struct kempld_gpio_data {26 struct gpio_chip chip;27 struct kempld_device_data *pld;28};29 30/*31 * Set or clear GPIO bit32 * kempld_get_mutex must be called prior to calling this function.33 */34static void kempld_gpio_bitop(struct kempld_device_data *pld,35 u8 reg, u8 bit, u8 val)36{37 u8 status;38 39 status = kempld_read8(pld, reg);40 if (val)41 status |= KEMPLD_GPIO_MASK(bit);42 else43 status &= ~KEMPLD_GPIO_MASK(bit);44 kempld_write8(pld, reg, status);45}46 47static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)48{49 u8 status;50 51 kempld_get_mutex(pld);52 status = kempld_read8(pld, reg);53 kempld_release_mutex(pld);54 55 return !!(status & KEMPLD_GPIO_MASK(bit));56}57 58static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)59{60 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);61 struct kempld_device_data *pld = gpio->pld;62 63 return !!kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset);64}65 66static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)67{68 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);69 struct kempld_device_data *pld = gpio->pld;70 71 kempld_get_mutex(pld);72 kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);73 kempld_release_mutex(pld);74}75 76static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)77{78 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);79 struct kempld_device_data *pld = gpio->pld;80 81 kempld_get_mutex(pld);82 kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0);83 kempld_release_mutex(pld);84 85 return 0;86}87 88static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,89 int value)90{91 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);92 struct kempld_device_data *pld = gpio->pld;93 94 kempld_get_mutex(pld);95 kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);96 kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1);97 kempld_release_mutex(pld);98 99 return 0;100}101 102static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)103{104 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);105 struct kempld_device_data *pld = gpio->pld;106 107 if (kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset))108 return GPIO_LINE_DIRECTION_OUT;109 110 return GPIO_LINE_DIRECTION_IN;111}112 113static int kempld_gpio_pincount(struct kempld_device_data *pld)114{115 u16 evt, evt_back;116 117 kempld_get_mutex(pld);118 119 /* Backup event register as it might be already initialized */120 evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);121 /* Clear event register */122 kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);123 /* Read back event register */124 evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);125 /* Restore event register */126 kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);127 128 kempld_release_mutex(pld);129 130 return evt ? __ffs(evt) : 16;131}132 133static int kempld_gpio_probe(struct platform_device *pdev)134{135 struct device *dev = &pdev->dev;136 struct kempld_device_data *pld = dev_get_drvdata(dev->parent);137 struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);138 struct kempld_gpio_data *gpio;139 struct gpio_chip *chip;140 int ret;141 142 if (pld->info.spec_major < 2) {143 dev_err(dev,144 "Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");145 return -ENODEV;146 }147 148 gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);149 if (!gpio)150 return -ENOMEM;151 152 gpio->pld = pld;153 154 platform_set_drvdata(pdev, gpio);155 156 chip = &gpio->chip;157 chip->label = "gpio-kempld";158 chip->owner = THIS_MODULE;159 chip->parent = dev;160 chip->can_sleep = true;161 if (pdata && pdata->gpio_base)162 chip->base = pdata->gpio_base;163 else164 chip->base = -1;165 chip->direction_input = kempld_gpio_direction_input;166 chip->direction_output = kempld_gpio_direction_output;167 chip->get_direction = kempld_gpio_get_direction;168 chip->get = kempld_gpio_get;169 chip->set = kempld_gpio_set;170 chip->ngpio = kempld_gpio_pincount(pld);171 if (chip->ngpio == 0) {172 dev_err(dev, "No GPIO pins detected\n");173 return -ENODEV;174 }175 176 ret = devm_gpiochip_add_data(dev, chip, gpio);177 if (ret) {178 dev_err(dev, "Could not register GPIO chip\n");179 return ret;180 }181 182 dev_info(dev, "GPIO functionality initialized with %d pins\n",183 chip->ngpio);184 185 return 0;186}187 188static struct platform_driver kempld_gpio_driver = {189 .driver = {190 .name = "kempld-gpio",191 },192 .probe = kempld_gpio_probe,193};194 195module_platform_driver(kempld_gpio_driver);196 197MODULE_DESCRIPTION("KEM PLD GPIO Driver");198MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");199MODULE_LICENSE("GPL");200MODULE_ALIAS("platform:kempld-gpio");201