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Commit d01b847c5cd070895c4ba178c85cd068a95cf7cd

Authored by Larry Johnson
Committed by Wolfgang Denk
1 parent 5a910c224b
Exists in master and in 54 other branches 8qm-imx_v2020.04_5.4.70_2.3.0, emb_lf_v2022.04, imx_v2015.04_4.1.15_1.0.0_ga, pitx_8mp_lf_v2020.04, smarc-8m-android-10.0.0_2.6.0, smarc-8m-android-11.0.0_2.0.0, smarc-8mp-android-11.0.0_2.0.0, smarc-emmc-imx_v2014.04_3.10.53_1.1.0_ga, smarc-emmc-imx_v2014.04_3.14.28_1.0.0_ga, smarc-imx-l5.0.0_1.0.0-ga, smarc-imx6_v2018.03_4.14.98_2.0.0_ga, smarc-imx7_v2017.03_4.9.11_1.0.0_ga, smarc-imx7_v2018.03_4.14.98_2.0.0_ga, smarc-imx_v2014.04_3.14.28_1.0.0_ga, smarc-imx_v2015.04_4.1.15_1.0.0_ga, smarc-imx_v2017.03_4.9.11_1.0.0_ga, smarc-imx_v2017.03_4.9.88_2.0.0_ga, smarc-imx_v2017.03_o8.1.0_1.3.0_8m, smarc-imx_v2018.03_4.14.78_1.0.0_ga, smarc-m6.0.1_2.1.0-ga, smarc-n7.1.2_2.0.0-ga, smarc-rel_imx_4.1.15_2.0.0_ga, smarc_8m-imx_v2018.03_4.14.98_2.0.0_ga, smarc_8m-imx_v2019.04_4.19.35_1.1.0, smarc_8m_00d0-imx_v2018.03_4.14.98_2.0.0_ga, smarc_8mm-imx_v2018.03_4.14.98_2.0.0_ga, smarc_8mm-imx_v2019.04_4.19.35_1.1.0, smarc_8mm-imx_v2020.04_5.4.24_2.1.0, smarc_8mp_lf_v2020.04, smarc_8mq-imx_v2020.04_5.4.24_2.1.0, smarc_8mq_lf_v2020.04, ti-u-boot-2015.07, u-boot-2013.01.y, v2013.10, v2013.10-smarct33, v2013.10-smartmen, v2014.01, v2014.04, v2014.04-smarct33, v2014.04-smarct33-emmc, v2014.04-smartmen, v2014.07, v2014.07-smarct33, v2014.07-smartmen, v2015.07-smarct33, v2015.07-smarct33-emmc, v2015.07-smarct4x, v2016.05-dlt, v2016.05-smarct3x, v2016.05-smarct3x-emmc, v2016.05-smarct4x, v2017.01-smarct3x, v2017.01-smarct3x-emmc, v2017.01-smarct4x

LM75 bug fix for negative temperatures 

When the LM75 temperature sensor measures a temperature below 0 C, the
current driver does not perform sign extension, so the result returned is
256 C too high.  This patch fixes the problem.

Signed-off-by: Larry Johnson <lrj@acm.org>

Showing 1 changed file with 7 additions and 1 deletions Inline Diff

drivers/hwmon/lm75.c
Diff comments   View file @ d01b847
1 /* 1 /*
2 * (C) Copyright 2001 2 * (C) Copyright 2001
3 * Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net 3 * Bill Hunter, Wave 7 Optics, williamhunter@mediaone.net
4 * 4 *
5 * See file CREDITS for list of people who contributed to this 5 * See file CREDITS for list of people who contributed to this
6 * project. 6 * project.
7 * 7 *
8 * This program is free software; you can redistribute it and/or 8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as 9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of 10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version. 11 * the License, or (at your option) any later version.
12 * 12 *
13 * This program is distributed in the hope that it will be useful, 13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details. 16 * GNU General Public License for more details.
17 * 17 *
18 * You should have received a copy of the GNU General Public License 18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software 19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA 21 * MA 02111-1307 USA
22 */ 22 */
23 23
24 /* 24 /*
25 * On Semiconductor's LM75 Temperature Sensor 25 * On Semiconductor's LM75 Temperature Sensor
26 */ 26 */
27 27
28 #include <common.h> 28 #include <common.h>
29 29
30 #ifdef CONFIG_DTT_LM75 30 #ifdef CONFIG_DTT_LM75
31 #if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \ 31 #if !defined(CFG_EEPROM_PAGE_WRITE_ENABLE) || \
32 (CFG_EEPROM_PAGE_WRITE_BITS < 1) 32 (CFG_EEPROM_PAGE_WRITE_BITS < 1)
33 # error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than 1 to use CONFIG_DTT_LM75" 33 # error "CFG_EEPROM_PAGE_WRITE_ENABLE must be defined and CFG_EEPROM_PAGE_WRITE_BITS must be greater than 1 to use CONFIG_DTT_LM75"
34 #endif 34 #endif
35 35
36 #include <i2c.h> 36 #include <i2c.h>
37 #include <dtt.h> 37 #include <dtt.h>
38 38
39 39
40 /* 40 /*
41 * Device code 41 * Device code
42 */ 42 */
43 #define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */ 43 #define DTT_I2C_DEV_CODE 0x48 /* ON Semi's LM75 device */
44 44
45 int dtt_read(int sensor, int reg) 45 int dtt_read(int sensor, int reg)
46 { 46 {
47 int dlen; 47 int dlen;
48 uchar data[2]; 48 uchar data[2];
49 49
50 /* 50 /*
51 * Validate 'reg' param 51 * Validate 'reg' param
52 */ 52 */
53 if((reg < 0) || (reg > 3)) 53 if((reg < 0) || (reg > 3))
54 return -1; 54 return -1;
55 55
56 /* 56 /*
57 * Calculate sensor address and register. 57 * Calculate sensor address and register.
58 */ 58 */
59 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */ 59 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
60 60
61 /* 61 /*
62 * Prepare to handle 2 byte result. 62 * Prepare to handle 2 byte result.
63 */ 63 */
64 if ((reg == DTT_READ_TEMP) || 64 if ((reg == DTT_READ_TEMP) ||
65 (reg == DTT_TEMP_HYST) || 65 (reg == DTT_TEMP_HYST) ||
66 (reg == DTT_TEMP_SET)) 66 (reg == DTT_TEMP_SET))
67 dlen = 2; 67 dlen = 2;
68 else 68 else
69 dlen = 1; 69 dlen = 1;
70 70
71 /* 71 /*
72 * Now try to read the register. 72 * Now try to read the register.
73 */ 73 */
74 if (i2c_read(sensor, reg, 1, data, dlen) != 0) 74 if (i2c_read(sensor, reg, 1, data, dlen) != 0)
75 return -1; 75 return -1;
76 76
77 /* 77 /*
78 * Handle 2 byte result. 78 * Handle 2 byte result.
79 */ 79 */
80 if (dlen == 2) 80 if (dlen == 2)
81 return ((int)((short)data[1] + (((short)data[0]) << 8))); 81 return ((int)((short)data[1] + (((short)data[0]) << 8)));
82 82
83 83
84 return (int)data[0]; 84 return (int)data[0];
85 } /* dtt_read() */ 85 } /* dtt_read() */
86 86
87 87
88 int dtt_write(int sensor, int reg, int val) 88 int dtt_write(int sensor, int reg, int val)
89 { 89 {
90 int dlen; 90 int dlen;
91 uchar data[2]; 91 uchar data[2];
92 92
93 /* 93 /*
94 * Validate 'reg' param 94 * Validate 'reg' param
95 */ 95 */
96 if ((reg < 0) || (reg > 3)) 96 if ((reg < 0) || (reg > 3))
97 return 1; 97 return 1;
98 98
99 /* 99 /*
100 * Calculate sensor address and register. 100 * Calculate sensor address and register.
101 */ 101 */
102 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */ 102 sensor = DTT_I2C_DEV_CODE + (sensor & 0x07); /* calculate address of lm75 */
103 103
104 /* 104 /*
105 * Handle 2 byte values. 105 * Handle 2 byte values.
106 */ 106 */
107 if ((reg == DTT_READ_TEMP) || 107 if ((reg == DTT_READ_TEMP) ||
108 (reg == DTT_TEMP_HYST) || 108 (reg == DTT_TEMP_HYST) ||
109 (reg == DTT_TEMP_SET)) { 109 (reg == DTT_TEMP_SET)) {
110 dlen = 2; 110 dlen = 2;
111 data[0] = (char)((val >> 8) & 0xff); /* MSB first */ 111 data[0] = (char)((val >> 8) & 0xff); /* MSB first */
112 data[1] = (char)(val & 0xff); 112 data[1] = (char)(val & 0xff);
113 } else { 113 } else {
114 dlen = 1; 114 dlen = 1;
115 data[0] = (char)(val & 0xff); 115 data[0] = (char)(val & 0xff);
116 } 116 }
117 117
118 /* 118 /*
119 * Write value to register. 119 * Write value to register.
120 */ 120 */
121 if (i2c_write(sensor, reg, 1, data, dlen) != 0) 121 if (i2c_write(sensor, reg, 1, data, dlen) != 0)
122 return 1; 122 return 1;
123 123
124 return 0; 124 return 0;
125 } /* dtt_write() */ 125 } /* dtt_write() */
126 126
127 127
128 static int _dtt_init(int sensor) 128 static int _dtt_init(int sensor)
129 { 129 {
130 int val; 130 int val;
131 131
132 /* 132 /*
133 * Setup TSET ( trip point ) register 133 * Setup TSET ( trip point ) register
134 */ 134 */
135 val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */ 135 val = ((CFG_DTT_MAX_TEMP * 2) << 7) & 0xff80; /* trip */
136 if (dtt_write(sensor, DTT_TEMP_SET, val) != 0) 136 if (dtt_write(sensor, DTT_TEMP_SET, val) != 0)
137 return 1; 137 return 1;
138 138
139 /* 139 /*
140 * Setup THYST ( untrip point ) register - Hysteresis 140 * Setup THYST ( untrip point ) register - Hysteresis
141 */ 141 */
142 val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80; 142 val = (((CFG_DTT_MAX_TEMP - CFG_DTT_HYSTERESIS) * 2) << 7) & 0xff80;
143 if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0) 143 if (dtt_write(sensor, DTT_TEMP_HYST, val) != 0)
144 return 1; 144 return 1;
145 145
146 /* 146 /*
147 * Setup configuraton register 147 * Setup configuraton register
148 */ 148 */
149 #ifdef CONFIG_DTT_AD7414 149 #ifdef CONFIG_DTT_AD7414
150 /* config = alert active low and disabled */ 150 /* config = alert active low and disabled */
151 val = 0x60; 151 val = 0x60;
152 #else 152 #else
153 /* config = 6 sample integration, int mode, active low, and enable */ 153 /* config = 6 sample integration, int mode, active low, and enable */
154 val = 0x18; 154 val = 0x18;
155 #endif 155 #endif
156 if (dtt_write(sensor, DTT_CONFIG, val) != 0) 156 if (dtt_write(sensor, DTT_CONFIG, val) != 0)
157 return 1; 157 return 1;
158 158
159 return 0; 159 return 0;
160 } /* _dtt_init() */ 160 } /* _dtt_init() */
161 161
162 162
163 int dtt_init (void) 163 int dtt_init (void)
164 { 164 {
165 int i; 165 int i;
166 unsigned char sensors[] = CONFIG_DTT_SENSORS; 166 unsigned char sensors[] = CONFIG_DTT_SENSORS;
167 const char *const header = "DTT: "; 167 const char *const header = "DTT: ";
168 168
169 for (i = 0; i < sizeof(sensors); i++) { 169 for (i = 0; i < sizeof(sensors); i++) {
170 if (_dtt_init(sensors[i]) != 0) 170 if (_dtt_init(sensors[i]) != 0)
171 printf("%s%d FAILED INIT\n", header, i+1); 171 printf("%s%d FAILED INIT\n", header, i+1);
172 else 172 else
173 printf("%s%d is %i C\n", header, i+1, 173 printf("%s%d is %i C\n", header, i+1,
174 dtt_get_temp(sensors[i])); 174 dtt_get_temp(sensors[i]));
175 } 175 }
176 176
177 return (0); 177 return (0);
178 } /* dtt_init() */ 178 } /* dtt_init() */
179 179
180 int dtt_get_temp(int sensor) 180 int dtt_get_temp(int sensor)
181 { 181 {
182 return (dtt_read(sensor, DTT_READ_TEMP) / 256); 182 int const ret = dtt_read(sensor, DTT_READ_TEMP);
183
184 if (ret < 0) {
185 printf("DTT temperature read failed.\n");
186 return 0;
187 }
188 return (int)((int16_t) ret / 256);
183 } /* dtt_get_temp() */ 189 } /* dtt_get_temp() */
184 190
185 #endif /* CONFIG_DTT_LM75 */ 191 #endif /* CONFIG_DTT_LM75 */
186 192