diff options
Diffstat (limited to 'drivers/gpio/gpio-logicvc.c')
| -rw-r--r-- | drivers/gpio/gpio-logicvc.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-logicvc.c b/drivers/gpio/gpio-logicvc.c new file mode 100644 index 0000000000..05d62011f3 --- /dev/null +++ b/drivers/gpio/gpio-logicvc.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019 Bootlin + * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com> + */ + +#include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> + +#define LOGICVC_CTRL_REG 0x40 +#define LOGICVC_CTRL_GPIO_SHIFT 11 +#define LOGICVC_CTRL_GPIO_BITS 5 + +#define LOGICVC_POWER_CTRL_REG 0x78 +#define LOGICVC_POWER_CTRL_GPIO_SHIFT 0 +#define LOGICVC_POWER_CTRL_GPIO_BITS 4 + +struct logicvc_gpio { + struct gpio_chip chip; + struct regmap *regmap; +}; + +static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset, + unsigned int *reg, unsigned int *bit) +{ + if (offset >= LOGICVC_CTRL_GPIO_BITS) { + *reg = LOGICVC_POWER_CTRL_REG; + + /* To the (virtual) power ctrl offset. */ + offset -= LOGICVC_CTRL_GPIO_BITS; + /* To the actual bit offset in reg. */ + offset += LOGICVC_POWER_CTRL_GPIO_SHIFT; + } else { + *reg = LOGICVC_CTRL_REG; + + /* To the actual bit offset in reg. */ + offset += LOGICVC_CTRL_GPIO_SHIFT; + } + + *bit = BIT(offset); +} + +static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct logicvc_gpio *logicvc = gpiochip_get_data(chip); + unsigned int reg, bit, value; + int ret; + + logicvc_gpio_offset(logicvc, offset, ®, &bit); + + ret = regmap_read(logicvc->regmap, reg, &value); + if (ret) + return ret; + + return !!(value & bit); +} + +static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value) +{ + struct logicvc_gpio *logicvc = gpiochip_get_data(chip); + unsigned int reg, bit; + + logicvc_gpio_offset(logicvc, offset, ®, &bit); + + regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0); +} + +static int logicvc_gpio_direction_output(struct gpio_chip *chip, + unsigned offset, int value) +{ + /* Pins are always configured as output, so just set the value. */ + logicvc_gpio_set(chip, offset, value); + + return 0; +} + +static struct regmap_config logicvc_gpio_regmap_config = { + .reg_bits = 32, + .val_bits = 32, + .reg_stride = 4, + .name = "logicvc-gpio", +}; + +static int logicvc_gpio_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *of_node = dev->of_node; + struct logicvc_gpio *logicvc; + int ret; + + logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL); + if (!logicvc) + return -ENOMEM; + + /* Try to get regmap from parent first. */ + logicvc->regmap = syscon_node_to_regmap(of_node->parent); + + /* Grab our own regmap if that fails. */ + if (IS_ERR(logicvc->regmap)) { + struct resource res; + void __iomem *base; + + ret = of_address_to_resource(of_node, 0, &res); + if (ret) { + dev_err(dev, "Failed to get resource from address\n"); + return ret; + } + + base = devm_ioremap_resource(dev, &res); + if (IS_ERR(base)) + return PTR_ERR(base); + + logicvc_gpio_regmap_config.max_register = resource_size(&res) - + logicvc_gpio_regmap_config.reg_stride; + + logicvc->regmap = + devm_regmap_init_mmio(dev, base, + &logicvc_gpio_regmap_config); + if (IS_ERR(logicvc->regmap)) { + dev_err(dev, "Failed to create regmap for I/O\n"); + return PTR_ERR(logicvc->regmap); + } + } + + logicvc->chip.parent = dev; + logicvc->chip.owner = THIS_MODULE; + logicvc->chip.label = dev_name(dev); + logicvc->chip.base = -1; + logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS + + LOGICVC_POWER_CTRL_GPIO_BITS; + logicvc->chip.get = logicvc_gpio_get; + logicvc->chip.set = logicvc_gpio_set; + logicvc->chip.direction_output = logicvc_gpio_direction_output; + + return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc); +} + +static const struct of_device_id logicivc_gpio_of_table[] = { + { + .compatible = "xylon,logicvc-3.02.a-gpio", + }, + { } +}; + +MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table); + +static struct platform_driver logicvc_gpio_driver = { + .driver = { + .name = "gpio-logicvc", + .of_match_table = logicivc_gpio_of_table, + }, + .probe = logicvc_gpio_probe, +}; + +module_platform_driver(logicvc_gpio_driver); + +MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>"); +MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver"); +MODULE_LICENSE("GPL"); |