1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2023 Loongson Technology Corporation Limited
4 */
5
6#include <drm/drm_managed.h>
7
8#include "lsdc_drv.h"
9#include "lsdc_output.h"
10
11/*
12 * __lsdc_gpio_i2c_set - set the state of a gpio pin indicated by mask
13 * @mask: gpio pin mask
14 * @state: "0" for low, "1" for high
15 */
16static void __lsdc_gpio_i2c_set(struct lsdc_i2c * const li2c, int mask, int state)
17{
18 struct lsdc_device *ldev = to_lsdc(ddev: li2c->ddev);
19 unsigned long flags;
20 u8 val;
21
22 spin_lock_irqsave(&ldev->reglock, flags);
23
24 if (state) {
25 /*
26 * Setting this pin as input directly, write 1 for input.
27 * The external pull-up resistor will pull the level up
28 */
29 val = readb(addr: li2c->dir_reg);
30 val |= mask;
31 writeb(val, addr: li2c->dir_reg);
32 } else {
33 /* First set this pin as output, write 0 for output */
34 val = readb(addr: li2c->dir_reg);
35 val &= ~mask;
36 writeb(val, addr: li2c->dir_reg);
37
38 /* Then, make this pin output 0 */
39 val = readb(addr: li2c->dat_reg);
40 val &= ~mask;
41 writeb(val, addr: li2c->dat_reg);
42 }
43
44 spin_unlock_irqrestore(lock: &ldev->reglock, flags);
45}
46
47/*
48 * __lsdc_gpio_i2c_get - read value back from the gpio pin indicated by mask
49 * @mask: gpio pin mask
50 * return "0" for low, "1" for high
51 */
52static int __lsdc_gpio_i2c_get(struct lsdc_i2c * const li2c, int mask)
53{
54 struct lsdc_device *ldev = to_lsdc(ddev: li2c->ddev);
55 unsigned long flags;
56 u8 val;
57
58 spin_lock_irqsave(&ldev->reglock, flags);
59
60 /* First set this pin as input */
61 val = readb(addr: li2c->dir_reg);
62 val |= mask;
63 writeb(val, addr: li2c->dir_reg);
64
65 /* Then get level state from this pin */
66 val = readb(addr: li2c->dat_reg);
67
68 spin_unlock_irqrestore(lock: &ldev->reglock, flags);
69
70 return (val & mask) ? 1 : 0;
71}
72
73static void lsdc_gpio_i2c_set_sda(void *i2c, int state)
74{
75 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
76 /* set state on the li2c->sda pin */
77 return __lsdc_gpio_i2c_set(li2c, mask: li2c->sda, state);
78}
79
80static void lsdc_gpio_i2c_set_scl(void *i2c, int state)
81{
82 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
83 /* set state on the li2c->scl pin */
84 return __lsdc_gpio_i2c_set(li2c, mask: li2c->scl, state);
85}
86
87static int lsdc_gpio_i2c_get_sda(void *i2c)
88{
89 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
90 /* read value from the li2c->sda pin */
91 return __lsdc_gpio_i2c_get(li2c, mask: li2c->sda);
92}
93
94static int lsdc_gpio_i2c_get_scl(void *i2c)
95{
96 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
97 /* read the value from the li2c->scl pin */
98 return __lsdc_gpio_i2c_get(li2c, mask: li2c->scl);
99}
100
101static void lsdc_destroy_i2c(struct drm_device *ddev, void *data)
102{
103 struct lsdc_i2c *li2c = (struct lsdc_i2c *)data;
104
105 if (li2c) {
106 i2c_del_adapter(adap: &li2c->adapter);
107 kfree(objp: li2c);
108 }
109}
110
111/*
112 * The DC in ls7a1000/ls7a2000/ls2k2000 has builtin gpio hardware
113 *
114 * @reg_base: gpio reg base
115 * @index: output channel index, 0 for PIPE0, 1 for PIPE1
116 */
117int lsdc_create_i2c_chan(struct drm_device *ddev,
118 struct lsdc_display_pipe *dispipe,
119 unsigned int index)
120{
121 struct lsdc_device *ldev = to_lsdc(ddev);
122 struct i2c_adapter *adapter;
123 struct lsdc_i2c *li2c;
124 int ret;
125
126 li2c = kzalloc(size: sizeof(*li2c), GFP_KERNEL);
127 if (!li2c)
128 return -ENOMEM;
129
130 dispipe->li2c = li2c;
131
132 if (index == 0) {
133 li2c->sda = 0x01; /* pin 0 */
134 li2c->scl = 0x02; /* pin 1 */
135 } else if (index == 1) {
136 li2c->sda = 0x04; /* pin 2 */
137 li2c->scl = 0x08; /* pin 3 */
138 } else {
139 return -ENOENT;
140 }
141
142 li2c->ddev = ddev;
143 li2c->dir_reg = ldev->reg_base + LS7A_DC_GPIO_DIR_REG;
144 li2c->dat_reg = ldev->reg_base + LS7A_DC_GPIO_DAT_REG;
145
146 li2c->bit.setsda = lsdc_gpio_i2c_set_sda;
147 li2c->bit.setscl = lsdc_gpio_i2c_set_scl;
148 li2c->bit.getsda = lsdc_gpio_i2c_get_sda;
149 li2c->bit.getscl = lsdc_gpio_i2c_get_scl;
150 li2c->bit.udelay = 5;
151 li2c->bit.timeout = usecs_to_jiffies(u: 2200);
152 li2c->bit.data = li2c;
153
154 adapter = &li2c->adapter;
155 adapter->algo_data = &li2c->bit;
156 adapter->owner = THIS_MODULE;
157 adapter->dev.parent = ddev->dev;
158 adapter->nr = -1;
159
160 snprintf(buf: adapter->name, size: sizeof(adapter->name), fmt: "lsdc-i2c%u", index);
161
162 i2c_set_adapdata(adap: adapter, data: li2c);
163
164 ret = i2c_bit_add_bus(adapter);
165 if (ret) {
166 kfree(objp: li2c);
167 return ret;
168 }
169
170 ret = drmm_add_action_or_reset(ddev, lsdc_destroy_i2c, li2c);
171 if (ret)
172 return ret;
173
174 drm_info(ddev, "%s(sda pin mask=%u, scl pin mask=%u) created\n",
175 adapter->name, li2c->sda, li2c->scl);
176
177 return 0;
178}
179

source code of linux/drivers/gpu/drm/loongson/lsdc_i2c.c