1// SPDX-License-Identifier: GPL-2.0+
2//
3// Synopsys CREG (Control REGisters) GPIO driver
4//
5// Copyright (C) 2018 Synopsys
6// Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
7
8#include <linux/gpio/driver.h>
9#include <linux/io.h>
10#include <linux/of.h>
11#include <linux/of_platform.h>
12
13#define MAX_GPIO 32
14
15struct creg_layout {
16 u8 ngpio;
17 u8 shift[MAX_GPIO];
18 u8 on[MAX_GPIO];
19 u8 off[MAX_GPIO];
20 u8 bit_per_gpio[MAX_GPIO];
21};
22
23struct creg_gpio {
24 struct gpio_chip gc;
25 void __iomem *regs;
26 spinlock_t lock;
27 const struct creg_layout *layout;
28};
29
30static void creg_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
31{
32 struct creg_gpio *hcg = gpiochip_get_data(gc);
33 const struct creg_layout *layout = hcg->layout;
34 u32 reg, reg_shift, value;
35 unsigned long flags;
36 int i;
37
38 value = val ? hcg->layout->on[offset] : hcg->layout->off[offset];
39
40 reg_shift = layout->shift[offset];
41 for (i = 0; i < offset; i++)
42 reg_shift += layout->bit_per_gpio[i] + layout->shift[i];
43
44 spin_lock_irqsave(&hcg->lock, flags);
45 reg = readl(hcg->regs);
46 reg &= ~(GENMASK(layout->bit_per_gpio[i] - 1, 0) << reg_shift);
47 reg |= (value << reg_shift);
48 writel(reg, hcg->regs);
49 spin_unlock_irqrestore(&hcg->lock, flags);
50}
51
52static int creg_gpio_dir_out(struct gpio_chip *gc, unsigned int offset, int val)
53{
54 creg_gpio_set(gc, offset, val);
55
56 return 0;
57}
58
59static int creg_gpio_validate_pg(struct device *dev, struct creg_gpio *hcg,
60 int i)
61{
62 const struct creg_layout *layout = hcg->layout;
63
64 if (layout->bit_per_gpio[i] < 1 || layout->bit_per_gpio[i] > 8)
65 return -EINVAL;
66
67 /* Check that on valiue fits it's placeholder */
68 if (GENMASK(31, layout->bit_per_gpio[i]) & layout->on[i])
69 return -EINVAL;
70
71 /* Check that off valiue fits it's placeholder */
72 if (GENMASK(31, layout->bit_per_gpio[i]) & layout->off[i])
73 return -EINVAL;
74
75 if (layout->on[i] == layout->off[i])
76 return -EINVAL;
77
78 return 0;
79}
80
81static int creg_gpio_validate(struct device *dev, struct creg_gpio *hcg,
82 u32 ngpios)
83{
84 u32 reg_len = 0;
85 int i;
86
87 if (hcg->layout->ngpio < 1 || hcg->layout->ngpio > MAX_GPIO)
88 return -EINVAL;
89
90 if (ngpios < 1 || ngpios > hcg->layout->ngpio) {
91 dev_err(dev, "ngpios must be in [1:%u]\n", hcg->layout->ngpio);
92 return -EINVAL;
93 }
94
95 for (i = 0; i < hcg->layout->ngpio; i++) {
96 if (creg_gpio_validate_pg(dev, hcg, i))
97 return -EINVAL;
98
99 reg_len += hcg->layout->shift[i] + hcg->layout->bit_per_gpio[i];
100 }
101
102 /* Check that we fit in 32 bit register */
103 if (reg_len > 32)
104 return -EINVAL;
105
106 return 0;
107}
108
109static const struct creg_layout hsdk_cs_ctl = {
110 .ngpio = 10,
111 .shift = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
112 .off = { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 },
113 .on = { 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 },
114 .bit_per_gpio = { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }
115};
116
117static const struct creg_layout axs10x_flsh_cs_ctl = {
118 .ngpio = 1,
119 .shift = { 0 },
120 .off = { 1 },
121 .on = { 3 },
122 .bit_per_gpio = { 2 }
123};
124
125static const struct of_device_id creg_gpio_ids[] = {
126 {
127 .compatible = "snps,creg-gpio-axs10x",
128 .data = &axs10x_flsh_cs_ctl
129 }, {
130 .compatible = "snps,creg-gpio-hsdk",
131 .data = &hsdk_cs_ctl
132 }, { /* sentinel */ }
133};
134
135static int creg_gpio_probe(struct platform_device *pdev)
136{
137 const struct of_device_id *match;
138 struct device *dev = &pdev->dev;
139 struct creg_gpio *hcg;
140 struct resource *mem;
141 u32 ngpios;
142 int ret;
143
144 hcg = devm_kzalloc(dev, sizeof(struct creg_gpio), GFP_KERNEL);
145 if (!hcg)
146 return -ENOMEM;
147
148 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149 hcg->regs = devm_ioremap_resource(dev, mem);
150 if (IS_ERR(hcg->regs))
151 return PTR_ERR(hcg->regs);
152
153 match = of_match_node(creg_gpio_ids, pdev->dev.of_node);
154 hcg->layout = match->data;
155 if (!hcg->layout)
156 return -EINVAL;
157
158 ret = of_property_read_u32(dev->of_node, "ngpios", &ngpios);
159 if (ret)
160 return ret;
161
162 ret = creg_gpio_validate(dev, hcg, ngpios);
163 if (ret)
164 return ret;
165
166 spin_lock_init(&hcg->lock);
167
168 hcg->gc.label = dev_name(dev);
169 hcg->gc.base = -1;
170 hcg->gc.ngpio = ngpios;
171 hcg->gc.set = creg_gpio_set;
172 hcg->gc.direction_output = creg_gpio_dir_out;
173 hcg->gc.of_node = dev->of_node;
174
175 ret = devm_gpiochip_add_data(dev, &hcg->gc, hcg);
176 if (ret)
177 return ret;
178
179 dev_info(dev, "GPIO controller with %d gpios probed\n", ngpios);
180
181 return 0;
182}
183
184static struct platform_driver creg_gpio_snps_driver = {
185 .driver = {
186 .name = "snps-creg-gpio",
187 .of_match_table = creg_gpio_ids,
188 },
189 .probe = creg_gpio_probe,
190};
191builtin_platform_driver(creg_gpio_snps_driver);
192