drivers/gpio/gpio-logicvc.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Copyright (C) 2019 Bootlin
0004  * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
0005  */
0006
0007 #include <linux/err.h>
0008 #include <linux/gpio/driver.h>
0009 #include <linux/module.h>
0010 #include <linux/of.h>
0011 #include <linux/of_device.h>
0012 #include <linux/of_address.h>
0013 #include <linux/platform_device.h>
0014 #include <linux/regmap.h>
0015 #include <linux/mfd/syscon.h>
0016
0017 #define LOGICVC_CTRL_REG        0x40
0018 #define LOGICVC_CTRL_GPIO_SHIFT     11
0019 #define LOGICVC_CTRL_GPIO_BITS      5
0020
0021 #define LOGICVC_POWER_CTRL_REG      0x78
0022 #define LOGICVC_POWER_CTRL_GPIO_SHIFT   0
0023 #define LOGICVC_POWER_CTRL_GPIO_BITS    4
0024
0025 struct logicvc_gpio {
0026     struct gpio_chip chip;
0027     struct regmap *regmap;
0028 };
0029
0030 static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
0031                 unsigned int *reg, unsigned int *bit)
0032 {
0033     if (offset >= LOGICVC_CTRL_GPIO_BITS) {
0034         *reg = LOGICVC_POWER_CTRL_REG;
0035
0036         /* To the (virtual) power ctrl offset. */
0037         offset -= LOGICVC_CTRL_GPIO_BITS;
0038         /* To the actual bit offset in reg. */
0039         offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
0040     } else {
0041         *reg = LOGICVC_CTRL_REG;
0042
0043         /* To the actual bit offset in reg. */
0044         offset += LOGICVC_CTRL_GPIO_SHIFT;
0045     }
0046
0047     *bit = BIT(offset);
0048 }
0049
0050 static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
0051 {
0052     struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
0053     unsigned int reg, bit, value;
0054     int ret;
0055
0056     logicvc_gpio_offset(logicvc, offset, &reg, &bit);
0057
0058     ret = regmap_read(logicvc->regmap, reg, &value);
0059     if (ret)
0060         return ret;
0061
0062     return !!(value & bit);
0063 }
0064
0065 static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
0066 {
0067     struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
0068     unsigned int reg, bit;
0069
0070     logicvc_gpio_offset(logicvc, offset, &reg, &bit);
0071
0072     regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
0073 }
0074
0075 static int logicvc_gpio_direction_output(struct gpio_chip *chip,
0076                      unsigned offset, int value)
0077 {
0078     /* Pins are always configured as output, so just set the value. */
0079     logicvc_gpio_set(chip, offset, value);
0080
0081     return 0;
0082 }
0083
0084 static struct regmap_config logicvc_gpio_regmap_config = {
0085     .reg_bits   = 32,
0086     .val_bits   = 32,
0087     .reg_stride = 4,
0088     .name       = "logicvc-gpio",
0089 };
0090
0091 static int logicvc_gpio_probe(struct platform_device *pdev)
0092 {
0093     struct device *dev = &pdev->dev;
0094     struct device_node *of_node = dev->of_node;
0095     struct logicvc_gpio *logicvc;
0096     int ret;
0097
0098     logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
0099     if (!logicvc)
0100         return -ENOMEM;
0101
0102     /* Try to get regmap from parent first. */
0103     logicvc->regmap = syscon_node_to_regmap(of_node->parent);
0104
0105     /* Grab our own regmap if that fails. */
0106     if (IS_ERR(logicvc->regmap)) {
0107         struct resource res;
0108         void __iomem *base;
0109
0110         ret = of_address_to_resource(of_node, 0, &res);
0111         if (ret) {
0112             dev_err(dev, "Failed to get resource from address\n");
0113             return ret;
0114         }
0115
0116         base = devm_ioremap_resource(dev, &res);
0117         if (IS_ERR(base))
0118             return PTR_ERR(base);
0119
0120         logicvc_gpio_regmap_config.max_register = resource_size(&res) -
0121             logicvc_gpio_regmap_config.reg_stride;
0122
0123         logicvc->regmap =
0124             devm_regmap_init_mmio(dev, base,
0125                           &logicvc_gpio_regmap_config);
0126         if (IS_ERR(logicvc->regmap)) {
0127             dev_err(dev, "Failed to create regmap for I/O\n");
0128             return PTR_ERR(logicvc->regmap);
0129         }
0130     }
0131
0132     logicvc->chip.parent = dev;
0133     logicvc->chip.owner = THIS_MODULE;
0134     logicvc->chip.label = dev_name(dev);
0135     logicvc->chip.base = -1;
0136     logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
0137                   LOGICVC_POWER_CTRL_GPIO_BITS;
0138     logicvc->chip.get = logicvc_gpio_get;
0139     logicvc->chip.set = logicvc_gpio_set;
0140     logicvc->chip.direction_output = logicvc_gpio_direction_output;
0141
0142     platform_set_drvdata(pdev, logicvc);
0143
0144     return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
0145 }
0146
0147 static const struct of_device_id logicivc_gpio_of_table[] = {
0148     {
0149         .compatible = "xylon,logicvc-3.02.a-gpio",
0150     },
0151     { }
0152 };
0153
0154 MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
0155
0156 static struct platform_driver logicvc_gpio_driver = {
0157     .driver = {
0158         .name       = "gpio-logicvc",
0159         .of_match_table = logicivc_gpio_of_table,
0160     },
0161     .probe  = logicvc_gpio_probe,
0162 };
0163
0164 module_platform_driver(logicvc_gpio_driver);
0165
0166 MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
0167 MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
0168 MODULE_LICENSE("GPL");