350 lines
8.8 KiB
C
350 lines
8.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* regmap based generic GPIO driver
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*
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* Copyright 2020 Michael Walle <michael@walle.cc>
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*/
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#include <linux/gpio/driver.h>
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#include <linux/gpio/regmap.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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struct gpio_regmap {
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struct device *parent;
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struct regmap *regmap;
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struct gpio_chip gpio_chip;
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int reg_stride;
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int ngpio_per_reg;
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unsigned int reg_dat_base;
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unsigned int reg_set_base;
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unsigned int reg_clr_base;
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unsigned int reg_dir_in_base;
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unsigned int reg_dir_out_base;
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int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,
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unsigned int offset, unsigned int *reg,
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unsigned int *mask);
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void *driver_data;
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};
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static unsigned int gpio_regmap_addr(unsigned int addr)
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{
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if (addr == GPIO_REGMAP_ADDR_ZERO)
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return 0;
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return addr;
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}
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static int gpio_regmap_simple_xlate(struct gpio_regmap *gpio,
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unsigned int base, unsigned int offset,
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unsigned int *reg, unsigned int *mask)
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{
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unsigned int line = offset % gpio->ngpio_per_reg;
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unsigned int stride = offset / gpio->ngpio_per_reg;
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*reg = base + stride * gpio->reg_stride;
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*mask = BIT(line);
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return 0;
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}
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static int gpio_regmap_get(struct gpio_chip *chip, unsigned int offset)
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{
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struct gpio_regmap *gpio = gpiochip_get_data(chip);
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unsigned int base, val, reg, mask;
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int ret;
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/* we might not have an output register if we are input only */
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if (gpio->reg_dat_base)
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base = gpio_regmap_addr(gpio->reg_dat_base);
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else
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base = gpio_regmap_addr(gpio->reg_set_base);
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ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
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if (ret)
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return ret;
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ret = regmap_read(gpio->regmap, reg, &val);
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if (ret)
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return ret;
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return !!(val & mask);
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}
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static void gpio_regmap_set(struct gpio_chip *chip, unsigned int offset,
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int val)
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{
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struct gpio_regmap *gpio = gpiochip_get_data(chip);
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unsigned int base = gpio_regmap_addr(gpio->reg_set_base);
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unsigned int reg, mask;
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gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
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if (val)
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regmap_update_bits(gpio->regmap, reg, mask, mask);
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else
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regmap_update_bits(gpio->regmap, reg, mask, 0);
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}
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static void gpio_regmap_set_with_clear(struct gpio_chip *chip,
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unsigned int offset, int val)
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{
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struct gpio_regmap *gpio = gpiochip_get_data(chip);
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unsigned int base, reg, mask;
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if (val)
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base = gpio_regmap_addr(gpio->reg_set_base);
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else
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base = gpio_regmap_addr(gpio->reg_clr_base);
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gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
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regmap_write(gpio->regmap, reg, mask);
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}
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static int gpio_regmap_get_direction(struct gpio_chip *chip,
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unsigned int offset)
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{
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struct gpio_regmap *gpio = gpiochip_get_data(chip);
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unsigned int base, val, reg, mask;
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int invert, ret;
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if (gpio->reg_dir_out_base) {
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base = gpio_regmap_addr(gpio->reg_dir_out_base);
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invert = 0;
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} else if (gpio->reg_dir_in_base) {
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base = gpio_regmap_addr(gpio->reg_dir_in_base);
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invert = 1;
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} else {
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return -EOPNOTSUPP;
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}
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ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
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if (ret)
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return ret;
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ret = regmap_read(gpio->regmap, reg, &val);
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if (ret)
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return ret;
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if (!!(val & mask) ^ invert)
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return GPIO_LINE_DIRECTION_OUT;
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else
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return GPIO_LINE_DIRECTION_IN;
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}
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static int gpio_regmap_set_direction(struct gpio_chip *chip,
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unsigned int offset, bool output)
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{
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struct gpio_regmap *gpio = gpiochip_get_data(chip);
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unsigned int base, val, reg, mask;
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int invert, ret;
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if (gpio->reg_dir_out_base) {
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base = gpio_regmap_addr(gpio->reg_dir_out_base);
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invert = 0;
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} else if (gpio->reg_dir_in_base) {
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base = gpio_regmap_addr(gpio->reg_dir_in_base);
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invert = 1;
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} else {
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return -EOPNOTSUPP;
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}
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ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
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if (ret)
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return ret;
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if (invert)
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val = output ? 0 : mask;
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else
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val = output ? mask : 0;
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return regmap_update_bits(gpio->regmap, reg, mask, val);
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}
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static int gpio_regmap_direction_input(struct gpio_chip *chip,
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unsigned int offset)
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{
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return gpio_regmap_set_direction(chip, offset, false);
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}
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static int gpio_regmap_direction_output(struct gpio_chip *chip,
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unsigned int offset, int value)
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{
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gpio_regmap_set(chip, offset, value);
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return gpio_regmap_set_direction(chip, offset, true);
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}
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void gpio_regmap_set_drvdata(struct gpio_regmap *gpio, void *data)
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{
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gpio->driver_data = data;
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}
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EXPORT_SYMBOL_GPL(gpio_regmap_set_drvdata);
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void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
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{
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return gpio->driver_data;
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}
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EXPORT_SYMBOL_GPL(gpio_regmap_get_drvdata);
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/**
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* gpio_regmap_register() - Register a generic regmap GPIO controller
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* @config: configuration for gpio_regmap
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*
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* Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
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*/
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struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)
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{
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struct gpio_regmap *gpio;
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struct gpio_chip *chip;
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int ret;
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if (!config->parent)
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return ERR_PTR(-EINVAL);
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if (!config->ngpio)
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return ERR_PTR(-EINVAL);
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/* we need at least one */
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if (!config->reg_dat_base && !config->reg_set_base)
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return ERR_PTR(-EINVAL);
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/* if we have a direction register we need both input and output */
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if ((config->reg_dir_out_base || config->reg_dir_in_base) &&
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(!config->reg_dat_base || !config->reg_set_base))
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return ERR_PTR(-EINVAL);
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/* we don't support having both registers simultaneously for now */
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if (config->reg_dir_out_base && config->reg_dir_in_base)
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return ERR_PTR(-EINVAL);
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gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
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if (!gpio)
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return ERR_PTR(-ENOMEM);
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gpio->parent = config->parent;
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gpio->regmap = config->regmap;
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gpio->ngpio_per_reg = config->ngpio_per_reg;
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gpio->reg_stride = config->reg_stride;
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gpio->reg_mask_xlate = config->reg_mask_xlate;
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gpio->reg_dat_base = config->reg_dat_base;
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gpio->reg_set_base = config->reg_set_base;
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gpio->reg_clr_base = config->reg_clr_base;
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gpio->reg_dir_in_base = config->reg_dir_in_base;
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gpio->reg_dir_out_base = config->reg_dir_out_base;
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/* if not set, assume there is only one register */
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if (!gpio->ngpio_per_reg)
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gpio->ngpio_per_reg = config->ngpio;
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/* if not set, assume they are consecutive */
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if (!gpio->reg_stride)
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gpio->reg_stride = 1;
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if (!gpio->reg_mask_xlate)
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gpio->reg_mask_xlate = gpio_regmap_simple_xlate;
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chip = &gpio->gpio_chip;
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chip->parent = config->parent;
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chip->base = -1;
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chip->ngpio = config->ngpio;
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chip->names = config->names;
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chip->label = config->label ?: dev_name(config->parent);
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/*
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* If our regmap is fast_io we should probably set can_sleep to false.
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* Right now, the regmap doesn't save this property, nor is there any
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* access function for it.
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* The only regmap type which uses fast_io is regmap-mmio. For now,
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* assume a safe default of true here.
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*/
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chip->can_sleep = true;
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chip->get = gpio_regmap_get;
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if (gpio->reg_set_base && gpio->reg_clr_base)
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chip->set = gpio_regmap_set_with_clear;
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else if (gpio->reg_set_base)
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chip->set = gpio_regmap_set;
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if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
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chip->get_direction = gpio_regmap_get_direction;
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chip->direction_input = gpio_regmap_direction_input;
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chip->direction_output = gpio_regmap_direction_output;
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}
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ret = gpiochip_add_data(chip, gpio);
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if (ret < 0)
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goto err_free_gpio;
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if (config->irq_domain) {
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ret = gpiochip_irqchip_add_domain(chip, config->irq_domain);
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if (ret)
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goto err_remove_gpiochip;
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}
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return gpio;
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err_remove_gpiochip:
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gpiochip_remove(chip);
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err_free_gpio:
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kfree(gpio);
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return ERR_PTR(ret);
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}
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EXPORT_SYMBOL_GPL(gpio_regmap_register);
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/**
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* gpio_regmap_unregister() - Unregister a generic regmap GPIO controller
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* @gpio: gpio_regmap device to unregister
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*/
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void gpio_regmap_unregister(struct gpio_regmap *gpio)
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{
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gpiochip_remove(&gpio->gpio_chip);
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kfree(gpio);
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}
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EXPORT_SYMBOL_GPL(gpio_regmap_unregister);
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static void devm_gpio_regmap_unregister(struct device *dev, void *res)
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{
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gpio_regmap_unregister(*(struct gpio_regmap **)res);
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}
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/**
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* devm_gpio_regmap_register() - resource managed gpio_regmap_register()
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* @dev: device that is registering this GPIO device
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* @config: configuration for gpio_regmap
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*
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* Managed gpio_regmap_register(). For generic regmap GPIO device registered by
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* this function, gpio_regmap_unregister() is automatically called on driver
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* detach. See gpio_regmap_register() for more information.
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*
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* Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
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*/
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struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
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const struct gpio_regmap_config *config)
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{
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struct gpio_regmap **ptr, *gpio;
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ptr = devres_alloc(devm_gpio_regmap_unregister, sizeof(*ptr),
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GFP_KERNEL);
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if (!ptr)
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return ERR_PTR(-ENOMEM);
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gpio = gpio_regmap_register(config);
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if (!IS_ERR(gpio)) {
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*ptr = gpio;
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devres_add(dev, ptr);
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} else {
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devres_free(ptr);
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}
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return gpio;
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}
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EXPORT_SYMBOL_GPL(devm_gpio_regmap_register);
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MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
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MODULE_DESCRIPTION("GPIO generic regmap driver core");
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MODULE_LICENSE("GPL");
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