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
15 struct 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
23 struct creg_gpio {
24 struct gpio_chip gc;
25 void __iomem *regs;
26 spinlock_t lock;
27 const struct creg_layout *layout;
28 };
29
creg_gpio_set(struct gpio_chip * gc,unsigned int offset,int val)30 static 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
creg_gpio_dir_out(struct gpio_chip * gc,unsigned int offset,int val)52 static 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
creg_gpio_validate_pg(struct device * dev,struct creg_gpio * hcg,int i)59 static 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 value fits its placeholder */
68 if (GENMASK(31, layout->bit_per_gpio[i]) & layout->on[i])
69 return -EINVAL;
70
71 /* Check that off value fits its 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
creg_gpio_validate(struct device * dev,struct creg_gpio * hcg,u32 ngpios)81 static 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
109 static 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
117 static 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
125 static 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
creg_gpio_probe(struct platform_device * pdev)135 static 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 u32 ngpios;
141 int ret;
142
143 hcg = devm_kzalloc(dev, sizeof(struct creg_gpio), GFP_KERNEL);
144 if (!hcg)
145 return -ENOMEM;
146
147 hcg->regs = devm_platform_ioremap_resource(pdev, 0);
148 if (IS_ERR(hcg->regs))
149 return PTR_ERR(hcg->regs);
150
151 match = of_match_node(creg_gpio_ids, pdev->dev.of_node);
152 hcg->layout = match->data;
153 if (!hcg->layout)
154 return -EINVAL;
155
156 ret = of_property_read_u32(dev->of_node, "ngpios", &ngpios);
157 if (ret)
158 return ret;
159
160 ret = creg_gpio_validate(dev, hcg, ngpios);
161 if (ret)
162 return ret;
163
164 spin_lock_init(&hcg->lock);
165
166 hcg->gc.label = dev_name(dev);
167 hcg->gc.base = -1;
168 hcg->gc.ngpio = ngpios;
169 hcg->gc.set = creg_gpio_set;
170 hcg->gc.direction_output = creg_gpio_dir_out;
171 hcg->gc.of_node = dev->of_node;
172
173 ret = devm_gpiochip_add_data(dev, &hcg->gc, hcg);
174 if (ret)
175 return ret;
176
177 dev_info(dev, "GPIO controller with %d gpios probed\n", ngpios);
178
179 return 0;
180 }
181
182 static struct platform_driver creg_gpio_snps_driver = {
183 .driver = {
184 .name = "snps-creg-gpio",
185 .of_match_table = creg_gpio_ids,
186 },
187 .probe = creg_gpio_probe,
188 };
189 builtin_platform_driver(creg_gpio_snps_driver);
190
