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 #include <drm/drm_print.h>
8
9 #include "lsdc_drv.h"
10 #include "lsdc_output.h"
11
12 /*
13 * __lsdc_gpio_i2c_set - set the state of a gpio pin indicated by mask
14 * @mask: gpio pin mask
15 * @state: "0" for low, "1" for high
16 */
__lsdc_gpio_i2c_set(struct lsdc_i2c * const li2c,int mask,int state)17 static void __lsdc_gpio_i2c_set(struct lsdc_i2c * const li2c, int mask, int state)
18 {
19 struct lsdc_device *ldev = to_lsdc(li2c->ddev);
20 unsigned long flags;
21 u8 val;
22
23 spin_lock_irqsave(&ldev->reglock, flags);
24
25 if (state) {
26 /*
27 * Setting this pin as input directly, write 1 for input.
28 * The external pull-up resistor will pull the level up
29 */
30 val = readb(li2c->dir_reg);
31 val |= mask;
32 writeb(val, li2c->dir_reg);
33 } else {
34 /* First set this pin as output, write 0 for output */
35 val = readb(li2c->dir_reg);
36 val &= ~mask;
37 writeb(val, li2c->dir_reg);
38
39 /* Then, make this pin output 0 */
40 val = readb(li2c->dat_reg);
41 val &= ~mask;
42 writeb(val, li2c->dat_reg);
43 }
44
45 spin_unlock_irqrestore(&ldev->reglock, flags);
46 }
47
48 /*
49 * __lsdc_gpio_i2c_get - read value back from the gpio pin indicated by mask
50 * @mask: gpio pin mask
51 * return "0" for low, "1" for high
52 */
__lsdc_gpio_i2c_get(struct lsdc_i2c * const li2c,int mask)53 static int __lsdc_gpio_i2c_get(struct lsdc_i2c * const li2c, int mask)
54 {
55 struct lsdc_device *ldev = to_lsdc(li2c->ddev);
56 unsigned long flags;
57 u8 val;
58
59 spin_lock_irqsave(&ldev->reglock, flags);
60
61 /* First set this pin as input */
62 val = readb(li2c->dir_reg);
63 val |= mask;
64 writeb(val, li2c->dir_reg);
65
66 /* Then get level state from this pin */
67 val = readb(li2c->dat_reg);
68
69 spin_unlock_irqrestore(&ldev->reglock, flags);
70
71 return (val & mask) ? 1 : 0;
72 }
73
lsdc_gpio_i2c_set_sda(void * i2c,int state)74 static void lsdc_gpio_i2c_set_sda(void *i2c, int state)
75 {
76 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
77 /* set state on the li2c->sda pin */
78 return __lsdc_gpio_i2c_set(li2c, li2c->sda, state);
79 }
80
lsdc_gpio_i2c_set_scl(void * i2c,int state)81 static void lsdc_gpio_i2c_set_scl(void *i2c, int state)
82 {
83 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
84 /* set state on the li2c->scl pin */
85 return __lsdc_gpio_i2c_set(li2c, li2c->scl, state);
86 }
87
lsdc_gpio_i2c_get_sda(void * i2c)88 static int lsdc_gpio_i2c_get_sda(void *i2c)
89 {
90 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
91 /* read value from the li2c->sda pin */
92 return __lsdc_gpio_i2c_get(li2c, li2c->sda);
93 }
94
lsdc_gpio_i2c_get_scl(void * i2c)95 static int lsdc_gpio_i2c_get_scl(void *i2c)
96 {
97 struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
98 /* read the value from the li2c->scl pin */
99 return __lsdc_gpio_i2c_get(li2c, li2c->scl);
100 }
101
lsdc_destroy_i2c(struct drm_device * ddev,void * data)102 static void lsdc_destroy_i2c(struct drm_device *ddev, void *data)
103 {
104 struct lsdc_i2c *li2c = (struct lsdc_i2c *)data;
105
106 if (li2c) {
107 i2c_del_adapter(&li2c->adapter);
108 kfree(li2c);
109 }
110 }
111
112 /*
113 * The DC in ls7a1000/ls7a2000/ls2k2000 has builtin gpio hardware
114 *
115 * @reg_base: gpio reg base
116 * @index: output channel index, 0 for PIPE0, 1 for PIPE1
117 */
lsdc_create_i2c_chan(struct drm_device * ddev,struct lsdc_display_pipe * dispipe,unsigned int index)118 int lsdc_create_i2c_chan(struct drm_device *ddev,
119 struct lsdc_display_pipe *dispipe,
120 unsigned int index)
121 {
122 struct lsdc_device *ldev = to_lsdc(ddev);
123 struct i2c_adapter *adapter;
124 struct lsdc_i2c *li2c;
125 int ret;
126
127 li2c = kzalloc_obj(*li2c);
128 if (!li2c)
129 return -ENOMEM;
130
131 dispipe->li2c = li2c;
132
133 if (index == 0) {
134 li2c->sda = 0x01; /* pin 0 */
135 li2c->scl = 0x02; /* pin 1 */
136 } else if (index == 1) {
137 li2c->sda = 0x04; /* pin 2 */
138 li2c->scl = 0x08; /* pin 3 */
139 } else {
140 return -ENOENT;
141 }
142
143 li2c->ddev = ddev;
144 li2c->dir_reg = ldev->reg_base + LS7A_DC_GPIO_DIR_REG;
145 li2c->dat_reg = ldev->reg_base + LS7A_DC_GPIO_DAT_REG;
146
147 li2c->bit.setsda = lsdc_gpio_i2c_set_sda;
148 li2c->bit.setscl = lsdc_gpio_i2c_set_scl;
149 li2c->bit.getsda = lsdc_gpio_i2c_get_sda;
150 li2c->bit.getscl = lsdc_gpio_i2c_get_scl;
151 li2c->bit.udelay = 5;
152 li2c->bit.timeout = usecs_to_jiffies(2200);
153 li2c->bit.data = li2c;
154
155 adapter = &li2c->adapter;
156 adapter->algo_data = &li2c->bit;
157 adapter->owner = THIS_MODULE;
158 adapter->dev.parent = ddev->dev;
159 adapter->nr = -1;
160
161 snprintf(adapter->name, sizeof(adapter->name), "lsdc-i2c%u", index);
162
163 i2c_set_adapdata(adapter, li2c);
164
165 ret = i2c_bit_add_bus(adapter);
166 if (ret) {
167 kfree(li2c);
168 return ret;
169 }
170
171 ret = drmm_add_action_or_reset(ddev, lsdc_destroy_i2c, li2c);
172 if (ret)
173 return ret;
174
175 drm_info(ddev, "%s(sda pin mask=%u, scl pin mask=%u) created\n",
176 adapter->name, li2c->sda, li2c->scl);
177
178 return 0;
179 }
180