gpio-idio-16.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * GPIO library for the ACCES IDIO-16 family
  4 * Copyright (C) 2022 William Breathitt Gray
  5 */
  6
  7#define DEFAULT_SYMBOL_NAMESPACE "GPIO_IDIO_16"
  8
  9#include <linux/bitmap.h>
 10#include <linux/bits.h>
 11#include <linux/device.h>
 12#include <linux/err.h>
 13#include <linux/export.h>
 14#include <linux/gpio/regmap.h>
 15#include <linux/module.h>
 16#include <linux/regmap.h>
 17#include <linux/types.h>
 18
 19#include "gpio-idio-16.h"
 20
 21#define IDIO_16_DAT_BASE 0x0
 22#define IDIO_16_OUT_BASE IDIO_16_DAT_BASE
 23#define IDIO_16_IN_BASE (IDIO_16_DAT_BASE + 1)
 24#define IDIO_16_CLEAR_INTERRUPT 0x1
 25#define IDIO_16_ENABLE_IRQ 0x2
 26#define IDIO_16_DEACTIVATE_INPUT_FILTERS 0x3
 27#define IDIO_16_DISABLE_IRQ IDIO_16_ENABLE_IRQ
 28#define IDIO_16_INTERRUPT_STATUS 0x6
 29
 30#define IDIO_16_NGPIO 32
 31#define IDIO_16_NGPIO_PER_REG 8
 32#define IDIO_16_REG_STRIDE 4
 33
 34struct idio_16_data {
 35	struct regmap *map;
 36	unsigned int irq_mask;
 37};
 38
 39static int idio_16_handle_mask_sync(const int index, const unsigned int mask_buf_def,
 40				    const unsigned int mask_buf, void *const irq_drv_data)
 41{
 42	struct idio_16_data *const data = irq_drv_data;
 43	const unsigned int prev_mask = data->irq_mask;
 44	int err;
 45	unsigned int val;
 46
 47	/* exit early if no change since the previous mask */
 48	if (mask_buf == prev_mask)
 49		return 0;
 50
 51	/* remember the current mask for the next mask sync */
 52	data->irq_mask = mask_buf;
 53
 54	/* if all previously masked, enable interrupts when unmasking */
 55	if (prev_mask == mask_buf_def) {
 56		err = regmap_write(data->map, IDIO_16_CLEAR_INTERRUPT, 0x00);
 57		if (err)
 58			return err;
 59		return regmap_read(data->map, IDIO_16_ENABLE_IRQ, &val);
 60	}
 61
 62	/* if all are currently masked, disable interrupts */
 63	if (mask_buf == mask_buf_def)
 64		return regmap_write(data->map, IDIO_16_DISABLE_IRQ, 0x00);
 65
 66	return 0;
 67}
 68
 69static int idio_16_reg_mask_xlate(struct gpio_regmap *const gpio, const unsigned int base,
 70				  const unsigned int offset, unsigned int *const reg,
 71				  unsigned int *const mask)
 72{
 73	unsigned int stride;
 74
 75	/* Input lines start at GPIO 16 */
 76	if (offset < 16) {
 77		stride = offset / IDIO_16_NGPIO_PER_REG;
 78		*reg = IDIO_16_OUT_BASE + stride * IDIO_16_REG_STRIDE;
 79	} else {
 80		stride = (offset - 16) / IDIO_16_NGPIO_PER_REG;
 81		*reg = IDIO_16_IN_BASE + stride * IDIO_16_REG_STRIDE;
 82	}
 83
 84	*mask = BIT(offset % IDIO_16_NGPIO_PER_REG);
 85
 86	return 0;
 87}
 88
 89static const char *idio_16_names[IDIO_16_NGPIO] = {
 90	"OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7",
 91	"OUT8", "OUT9", "OUT10", "OUT11", "OUT12", "OUT13", "OUT14", "OUT15",
 92	"IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5", "IIN6", "IIN7",
 93	"IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15",
 94};
 95
 96/**
 97 * devm_idio_16_regmap_register - Register an IDIO-16 GPIO device
 98 * @dev:	device that is registering this IDIO-16 GPIO device
 99 * @config:	configuration for idio_16_regmap_config
100 *
101 * Registers an IDIO-16 GPIO device. Returns 0 on success and negative error number on failure.
102 */
103int devm_idio_16_regmap_register(struct device *const dev,
104				 const struct idio_16_regmap_config *const config)
105{
106	struct gpio_regmap_config gpio_config = {};
107	int err;
108	struct idio_16_data *data;
109	struct regmap_irq_chip *chip;
110	struct regmap_irq_chip_data *chip_data;
111	DECLARE_BITMAP(fixed_direction_output, IDIO_16_NGPIO);
112
113	if (!config->parent)
114		return -EINVAL;
115
116	if (!config->map)
117		return -EINVAL;
118
119	if (!config->regmap_irqs)
120		return -EINVAL;
121
122	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
123	if (!data)
124		return -ENOMEM;
125	data->map = config->map;
126
127	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
128	if (!chip)
129		return -ENOMEM;
130
131	chip->name = dev_name(dev);
132	chip->status_base = IDIO_16_INTERRUPT_STATUS;
133	chip->mask_base = IDIO_16_ENABLE_IRQ;
134	chip->ack_base = IDIO_16_CLEAR_INTERRUPT;
135	chip->no_status = config->no_status;
136	chip->num_regs = 1;
137	chip->irqs = config->regmap_irqs;
138	chip->num_irqs = config->num_regmap_irqs;
139	chip->handle_mask_sync = idio_16_handle_mask_sync;
140	chip->irq_drv_data = data;
141
142	/* Disable IRQ to prevent spurious interrupts before we're ready */
143	err = regmap_write(data->map, IDIO_16_DISABLE_IRQ, 0x00);
144	if (err)
145		return err;
146
147	err = devm_regmap_add_irq_chip(dev, data->map, config->irq, 0, 0, chip, &chip_data);
148	if (err)
149		return dev_err_probe(dev, err, "IRQ registration failed\n");
150
151	if (config->filters) {
152		/* Deactivate input filters */
153		err = regmap_write(data->map, IDIO_16_DEACTIVATE_INPUT_FILTERS, 0x00);
154		if (err)
155			return err;
156	}
157
158	gpio_config.parent = config->parent;
159	gpio_config.regmap = data->map;
160	gpio_config.ngpio = IDIO_16_NGPIO;
161	gpio_config.names = idio_16_names;
162	gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(IDIO_16_DAT_BASE);
163	gpio_config.reg_set_base = GPIO_REGMAP_ADDR(IDIO_16_DAT_BASE);
164	gpio_config.ngpio_per_reg = IDIO_16_NGPIO_PER_REG;
165	gpio_config.reg_stride = IDIO_16_REG_STRIDE;
166	gpio_config.irq_domain = regmap_irq_get_domain(chip_data);
167	gpio_config.reg_mask_xlate = idio_16_reg_mask_xlate;
168
169	bitmap_from_u64(fixed_direction_output, GENMASK_U64(15, 0));
170	gpio_config.fixed_direction_output = fixed_direction_output;
171
172	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
173}
174EXPORT_SYMBOL_GPL(devm_idio_16_regmap_register);
175
176MODULE_AUTHOR("William Breathitt Gray");
177MODULE_DESCRIPTION("ACCES IDIO-16 GPIO Library");
178MODULE_LICENSE("GPL");