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 struct resource *res; 27 void __iomem *base_addr; 28 int retval; 29 u32 ngpios; 30 31 chip = devm_kzalloc(&pdev->dev, sizeof(struct gpio_chip), GFP_KERNEL); 32 if (!chip) 33 return -ENOMEM; 34 35 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 36 base_addr = devm_ioremap_resource(&pdev->dev, res); 37 if (IS_ERR(base_addr)) 38 return PTR_ERR(base_addr); 39 40 node = pdev->dev.of_node; 41 if (!node) 42 return -EINVAL; 43 44 retval = of_property_read_u32(node, "ngpios", &ngpios); 45 if (retval == -EINVAL) 46 ngpios = DEFAULT_PIN_NUMBER; 47 else if (retval) 48 return retval; 49 50 retval = bgpio_init(chip, &pdev->dev, 2, base_addr + INPUT_REG_OFFSET, 51 base_addr + OUTPUT_REG_OFFSET, NULL, 52 base_addr + DIRECTION_REG_OFFSET, NULL, 0); 53 if (retval) { 54 dev_err(&pdev->dev, "bgpio_init failed\n"); 55 return retval; 56 } 57 58 chip->ngpio = ngpios; 59 60 platform_set_drvdata(pdev, chip); 61 62 return devm_gpiochip_add_data(&pdev->dev, chip, NULL); 63 } 64 65 static const struct of_device_id ts4800_gpio_of_match[] = { 66 { .compatible = "technologic,ts4800-gpio", }, 67 {}, 68 }; 69 MODULE_DEVICE_TABLE(of, ts4800_gpio_of_match); 70 71 static struct platform_driver ts4800_gpio_driver = { 72 .driver = { 73 .name = "ts4800-gpio", 74 .of_match_table = ts4800_gpio_of_match, 75 }, 76 .probe = ts4800_gpio_probe, 77 }; 78 79 module_platform_driver_probe(ts4800_gpio_driver, ts4800_gpio_probe); 80 81 MODULE_AUTHOR("Julien Grossholtz <julien.grossholtz@savoirfairelinux.com>"); 82 MODULE_DESCRIPTION("TS4800 FPGA GPIO driver"); 83 MODULE_LICENSE("GPL v2"); 84