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
34 struct idio_16_data {
35 struct regmap *map;
36 unsigned int irq_mask;
37 };
38
idio_16_handle_mask_sync(const int index,const unsigned int mask_buf_def,const unsigned int mask_buf,void * const irq_drv_data)39 static 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
idio_16_reg_mask_xlate(struct gpio_regmap * const gpio,const unsigned int base,const unsigned int offset,unsigned int * const reg,unsigned int * const mask)69 static 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
89 static 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 */
devm_idio_16_regmap_register(struct device * const dev,const struct idio_16_regmap_config * const config)103 int 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 }
174 EXPORT_SYMBOL_GPL(devm_idio_16_regmap_register);
175
176 MODULE_AUTHOR("William Breathitt Gray");
177 MODULE_DESCRIPTION("ACCES IDIO-16 GPIO Library");
178 MODULE_LICENSE("GPL");
179