]>
Commit | Line | Data |
---|---|---|
d4024bb7 | 1 | /* |
1a459660 | 2 | * SPDX-License-Identifier: GPL-2.0+ |
d4024bb7 JO |
3 | */ |
4 | ||
5 | /* | |
6 | * Dallas Semiconductor's DS1775 Digital Thermometer and Thermostat | |
7 | */ | |
8 | ||
9 | #include <common.h> | |
10 | ||
d4024bb7 JO |
11 | #include <i2c.h> |
12 | #include <dtt.h> | |
13 | ||
6d0f6bcf | 14 | #define DTT_I2C_DEV_CODE CONFIG_SYS_I2C_DTT_ADDR /* Dallas Semi's DS1775 device code */ |
6ecbb45b MS |
15 | #define DTT_READ_TEMP 0x0 |
16 | #define DTT_CONFIG 0x1 | |
17 | #define DTT_TEMP_HYST 0x2 | |
18 | #define DTT_TEMP_OS 0x3 | |
d4024bb7 JO |
19 | |
20 | int dtt_read(int sensor, int reg) | |
21 | { | |
22 | int dlen; | |
23 | uchar data[2]; | |
24 | ||
25 | /* | |
26 | * Calculate sensor address and command | |
27 | */ | |
28 | sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* Calculate addr of ds1775 */ | |
29 | ||
30 | /* | |
31 | * Prepare to handle 2 byte result | |
32 | */ | |
33 | if ((reg == DTT_READ_TEMP) || | |
34 | (reg == DTT_TEMP_OS) || (reg == DTT_TEMP_HYST)) | |
35 | dlen = 2; | |
36 | else | |
37 | dlen = 1; | |
38 | ||
39 | /* | |
40 | * Now try to read the register | |
41 | */ | |
42 | if (i2c_read(sensor, reg, 1, data, dlen) != 0) | |
43 | return 1; | |
44 | ||
45 | /* | |
46 | * Handle 2 byte result | |
47 | */ | |
48 | if (dlen == 2) | |
49 | return ((int)((short)data[1] + (((short)data[0]) << 8))); | |
50 | ||
51 | return (int) data[0]; | |
52 | } | |
53 | ||
54 | ||
55 | int dtt_write(int sensor, int reg, int val) | |
56 | { | |
57 | int dlen; | |
58 | uchar data[2]; | |
59 | ||
60 | /* | |
61 | * Calculate sensor address and register | |
62 | */ | |
63 | sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); | |
64 | ||
65 | /* | |
66 | * Handle various data sizes | |
67 | */ | |
68 | if ((reg == DTT_READ_TEMP) || | |
69 | (reg == DTT_TEMP_OS) || (reg == DTT_TEMP_HYST)) { | |
70 | dlen = 2; | |
71 | data[0] = (char)((val >> 8) & 0xff); /* MSB first */ | |
72 | data[1] = (char)(val & 0xff); | |
73 | } else { | |
74 | dlen = 1; | |
75 | data[0] = (char)(val & 0xff); | |
76 | } | |
77 | ||
78 | /* | |
79 | * Write value to device | |
80 | */ | |
81 | if (i2c_write(sensor, reg, 1, data, dlen) != 0) | |
82 | return 1; | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | ||
780f13a9 | 88 | int dtt_init_one(int sensor) |
d4024bb7 JO |
89 | { |
90 | int val; | |
91 | ||
92 | /* | |
93 | * Setup High Temp | |
94 | */ | |
6d0f6bcf | 95 | val = ((CONFIG_SYS_DTT_MAX_TEMP * 2) << 7) & 0xff80; |
d4024bb7 JO |
96 | if (dtt_write(sensor, DTT_TEMP_OS, val) != 0) |
97 | return 1; | |
98 | udelay(50000); /* Max 50ms */ | |
99 | ||
100 | /* | |
101 | * Setup Low Temp - hysteresis | |
102 | */ | |
6d0f6bcf | 103 | val = (((CONFIG_SYS_DTT_MAX_TEMP - CONFIG_SYS_DTT_HYSTERESIS) * 2) << 7) & 0xff80; |
d4024bb7 JO |
104 | if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0) |
105 | return 1; | |
106 | udelay(50000); /* Max 50ms */ | |
107 | ||
108 | /* | |
109 | * Setup configuraton register | |
110 | * | |
111 | * Fault Tolerance limits 4, Thermometer resolution bits is 9, | |
112 | * Polarity = Active Low,continuous conversion mode, Thermostat | |
113 | * mode is interrupt mode | |
114 | */ | |
115 | val = 0xa; | |
116 | if (dtt_write(sensor, DTT_CONFIG, val) != 0) | |
117 | return 1; | |
118 | udelay(50000); /* Max 50ms */ | |
119 | ||
120 | return 0; | |
121 | } | |
122 | ||
d4024bb7 JO |
123 | int dtt_get_temp(int sensor) |
124 | { | |
125 | return (dtt_read(sensor, DTT_READ_TEMP) / 256); | |
126 | } |