1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Sample SPMI bus driver
4 *
5 * It emulates bus with single pm8916-like pmic that has only GPIO reigsters.
6 *
7 * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
8 */
9
10 #include <common.h>
11 #include <dm.h>
12 #include <errno.h>
13 #include <spmi/spmi.h>
14 #include <asm/gpio.h>
15 #include <asm/io.h>
16
17 #define EMUL_GPIO_PID_START 0xC0
18 #define EMUL_GPIO_PID_END 0xC3
19
20 #define EMUL_GPIO_COUNT 4
21
22 #define EMUL_GPIO_REG_END 0x46 /* Last valid register */
23
24 #define EMUL_PERM_R 0x1
25 #define EMUL_PERM_W 0x2
26 #define EMUL_PERM_RW (EMUL_PERM_R | EMUL_PERM_W)
27
28 struct sandbox_emul_fake_regs {
29 u8 value;
30 u8 access_mask;
31 u8 perms; /* Access permissions */
32 };
33
34 struct sandbox_emul_gpio {
35 /* Fake registers - need one more entry as REG_END is valid address. */
36 struct sandbox_emul_fake_regs r[EMUL_GPIO_REG_END + 1];
37 };
38
39 struct sandbox_spmi_priv {
40 struct sandbox_emul_gpio gpios[EMUL_GPIO_COUNT];
41 };
42
43 /* Check if valid register was requested */
check_address_valid(int usid,int pid,int off)44 static bool check_address_valid(int usid, int pid, int off)
45 {
46 if (usid != 0)
47 return false;
48 if (pid < EMUL_GPIO_PID_START || pid > EMUL_GPIO_PID_END)
49 return false;
50 if (off > EMUL_GPIO_REG_END)
51 return false;
52 return true;
53 }
54
sandbox_spmi_write(struct udevice * dev,int usid,int pid,int off,uint8_t val)55 static int sandbox_spmi_write(struct udevice *dev, int usid, int pid, int off,
56 uint8_t val)
57 {
58 struct sandbox_spmi_priv *priv = dev_get_priv(dev);
59 struct sandbox_emul_fake_regs *regs;
60
61 if (!check_address_valid(usid, pid, off))
62 return -EIO;
63
64 regs = priv->gpios[pid & 0x3].r; /* Last 3 bits of pid are gpio # */
65
66 switch (off) {
67 case 0x40: /* Control */
68 val &= regs[off].access_mask;
69 if (((val & 0x30) == 0x10) || ((val & 0x30) == 0x20)) {
70 /* out/inout - set status register */
71 regs[0x8].value &= ~0x1;
72 regs[0x8].value |= val & 0x1;
73 }
74 break;
75 default:
76 if (regs[off].perms & EMUL_PERM_W)
77 regs[off].value = val & regs[off].access_mask;
78 }
79 return 0;
80 }
81
sandbox_spmi_read(struct udevice * dev,int usid,int pid,int off)82 static int sandbox_spmi_read(struct udevice *dev, int usid, int pid, int off)
83 {
84 struct sandbox_spmi_priv *priv = dev_get_priv(dev);
85 struct sandbox_emul_fake_regs *regs;
86
87 if (!check_address_valid(usid, pid, off))
88 return -EIO;
89
90 regs = priv->gpios[pid & 0x3].r; /* Last 3 bits of pid are gpio # */
91
92 if (regs[0x46].value == 0) /* Block disabled */
93 return 0;
94
95 switch (off) {
96 case 0x8: /* Status */
97 if (regs[0x46].value == 0) /* Block disabled */
98 return 0;
99 return regs[off].value;
100 default:
101 if (regs[off].perms & EMUL_PERM_R)
102 return regs[off].value;
103 else
104 return 0;
105 }
106 }
107
108 static struct dm_spmi_ops sandbox_spmi_ops = {
109 .read = sandbox_spmi_read,
110 .write = sandbox_spmi_write,
111 };
112
sandbox_spmi_probe(struct udevice * dev)113 static int sandbox_spmi_probe(struct udevice *dev)
114 {
115 struct sandbox_spmi_priv *priv = dev_get_priv(dev);
116 int i;
117
118 for (i = 0; i < EMUL_GPIO_COUNT; ++i) {
119 struct sandbox_emul_fake_regs *regs = priv->gpios[i].r;
120 regs[4].perms = EMUL_PERM_R;
121 regs[4].value = 0x10;
122 regs[5].perms = EMUL_PERM_R;
123 regs[5].value = 0x5;
124 regs[8].access_mask = 0x81;
125 regs[8].perms = EMUL_PERM_RW;
126 regs[0x40].access_mask = 0x7F;
127 regs[0x40].perms = EMUL_PERM_RW;
128 regs[0x41].access_mask = 7;
129 regs[0x41].perms = EMUL_PERM_RW;
130 regs[0x42].access_mask = 7;
131 regs[0x42].perms = EMUL_PERM_RW;
132 regs[0x42].value = 0x4;
133 regs[0x45].access_mask = 0x3F;
134 regs[0x45].perms = EMUL_PERM_RW;
135 regs[0x45].value = 0x1;
136 regs[0x46].access_mask = 0x80;
137 regs[0x46].perms = EMUL_PERM_RW;
138 regs[0x46].value = 0x80;
139 }
140 return 0;
141 }
142
143 static const struct udevice_id sandbox_spmi_ids[] = {
144 { .compatible = "sandbox,spmi" },
145 { }
146 };
147
148 U_BOOT_DRIVER(msm_spmi) = {
149 .name = "sandbox_spmi",
150 .id = UCLASS_SPMI,
151 .of_match = sandbox_spmi_ids,
152 .ops = &sandbox_spmi_ops,
153 .probe = sandbox_spmi_probe,
154 .priv_auto_alloc_size = sizeof(struct sandbox_spmi_priv),
155 };
156