1 /* 2 * GPIO driver for the TS-4800 board 3 * 4 * Copyright (c) 2016 - Savoir-faire Linux 5 * 6 * This file is licensed under the terms of the GNU General Public 7 * License version 2. This program is licensed "as is" without any 8 * warranty of any kind, whether express or implied. 9 */ 10 11 #include <linux/gpio/driver.h> 12 #include <linux/module.h> 13 #include <linux/of_address.h> 14 #include <linux/of_device.h> 15 #include <linux/platform_device.h> 16 17 #define DEFAULT_PIN_NUMBER 16 18 #define INPUT_REG_OFFSET 0x00 19 #define OUTPUT_REG_OFFSET 0x02 20 #define DIRECTION_REG_OFFSET 0x04 21 22 static int ts4800_gpio_probe(struct platform_device *pdev) 23 { 24 struct device_node *node; 25 struct gpio_chip *chip; 26 void __iomem *base_addr; 27 int retval; 28 u32 ngpios; 29 30 chip = devm_kzalloc(&pdev->dev, sizeof(struct gpio_chip), GFP_KERNEL); 31 if (!chip) 32 return -ENOMEM; 33 34 base_addr = devm_platform_ioremap_resource(pdev, 0); 35 if (IS_ERR(base_addr)) 36 return PTR_ERR(base_addr); 37 38 node = pdev->dev.of_node; 39 if (!node) 40 return -EINVAL; 41 42 retval = of_property_read_u32(node, "ngpios", &ngpios); 43 if (retval == -EINVAL) 44 ngpios = DEFAULT_PIN_NUMBER; 45 else if (retval) 46 return retval; 47 48 retval = bgpio_init(chip, &pdev->dev, 2, base_addr + INPUT_REG_OFFSET, 49 base_addr + OUTPUT_REG_OFFSET, NULL, 50 base_addr + DIRECTION_REG_OFFSET, NULL, 0); 51 if (retval) { 52 dev_err(&pdev->dev, "bgpio_init failed\n"); 53 return retval; 54 } 55 56 chip->ngpio = ngpios; 57 58 platform_set_drvdata(pdev, chip); 59 60 return devm_gpiochip_add_data(&pdev->dev, chip, NULL); 61 } 62 63 static const struct of_device_id ts4800_gpio_of_match[] = { 64 { .compatible = "technologic,ts4800-gpio", }, 65 {}, 66 }; 67 MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match); 68 69 static struct platform_driver ts4800_gpio_driver = { 70 .driver = { 71 .name = "ts4800-gpio", 72 .of_match_table = ts4800_gpio_of_match, 73 }, 74 .probe = ts4800_gpio_probe, 75 }; 76 77 module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe); 78 79 MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>"); 80 MODULE_DESCRIPTION("TS4800 FPGA GPIO driver"); 81 MODULE_LICENSE("GPL v2"); 82