1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * GPIO driver for the TS-4800 board 4 * 5 * Copyright (c) 2016 - Savoir-faire Linux 6 */ 7 8 #include <linux/gpio/driver.h> 9 #include <linux/gpio/generic.h> 10 #include <linux/module.h> 11 #include <linux/platform_device.h> 12 #include <linux/property.h> 13 14 #define DEFAULT_PIN_NUMBER 16 15 #define INPUT_REG_OFFSET 0x00 16 #define OUTPUT_REG_OFFSET 0x02 17 #define DIRECTION_REG_OFFSET 0x04 18 19 static int ts4800_gpio_probe(struct platform_device *pdev) 20 { 21 struct gpio_generic_chip_config config; 22 struct device *dev = &pdev->dev; 23 struct gpio_generic_chip *chip; 24 void __iomem *base_addr; 25 int retval; 26 u32 ngpios; 27 28 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); 29 if (!chip) 30 return -ENOMEM; 31 32 base_addr = devm_platform_ioremap_resource(pdev, 0); 33 if (IS_ERR(base_addr)) 34 return PTR_ERR(base_addr); 35 36 retval = device_property_read_u32(dev, "ngpios", &ngpios); 37 if (retval == -EINVAL) 38 ngpios = DEFAULT_PIN_NUMBER; 39 else if (retval) 40 return retval; 41 42 config = (struct gpio_generic_chip_config) { 43 .dev = dev, 44 .sz = 2, 45 .dat = base_addr + INPUT_REG_OFFSET, 46 .set = base_addr + OUTPUT_REG_OFFSET, 47 .dirout = base_addr + DIRECTION_REG_OFFSET, 48 }; 49 50 retval = gpio_generic_chip_init(chip, &config); 51 if (retval) 52 return dev_err_probe(dev, retval, 53 "failed to initialize the generic GPIO chip\n"); 54 55 chip->gc.ngpio = ngpios; 56 57 return devm_gpiochip_add_data(dev, &chip->gc, NULL); 58 } 59 60 static const struct of_device_id ts4800_gpio_of_match[] = { 61 { .compatible = "technologic,ts4800-gpio", }, 62 {}, 63 }; 64 MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match); 65 66 static struct platform_driver ts4800_gpio_driver = { 67 .driver = { 68 .name = "ts4800-gpio", 69 .of_match_table = ts4800_gpio_of_match, 70 }, 71 .probe = ts4800_gpio_probe, 72 }; 73 74 module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe); 75 76 MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>"); 77 MODULE_DESCRIPTION("TS4800 FPGA GPIO driver"); 78 MODULE_LICENSE("GPL v2"); 79