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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Windfarm PowerMac thermal control. LM87 sensor4 *5 * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.6 */7 8#include <linux/types.h>9#include <linux/errno.h>10#include <linux/kernel.h>11#include <linux/delay.h>12#include <linux/slab.h>13#include <linux/init.h>14#include <linux/wait.h>15#include <linux/i2c.h>16 17#include <asm/machdep.h>18#include <asm/io.h>19#include <asm/sections.h>20#include <asm/pmac_low_i2c.h>21 22#include "windfarm.h"23 24#define VERSION "1.0"25 26#undef DEBUG27 28#ifdef DEBUG29#define DBG(args...) printk(args)30#else31#define DBG(args...) do { } while(0)32#endif33 34struct wf_lm87_sensor {35 struct i2c_client *i2c;36 struct wf_sensor sens;37};38#define wf_to_lm87(c) container_of(c, struct wf_lm87_sensor, sens)39 40 41static int wf_lm87_read_reg(struct i2c_client *chip, int reg)42{43 int rc, tries = 0;44 u8 buf;45 46 for (;;) {47 /* Set address */48 buf = (u8)reg;49 rc = i2c_master_send(chip, &buf, 1);50 if (rc <= 0)51 goto error;52 rc = i2c_master_recv(chip, &buf, 1);53 if (rc <= 0)54 goto error;55 return (int)buf;56 error:57 DBG("wf_lm87: Error reading LM87, retrying...\n");58 if (++tries > 10) {59 printk(KERN_ERR "wf_lm87: Error reading LM87 !\n");60 return -EIO;61 }62 msleep(10);63 }64}65 66static int wf_lm87_get(struct wf_sensor *sr, s32 *value)67{68 struct wf_lm87_sensor *lm = sr->priv;69 s32 temp;70 71 if (lm->i2c == NULL)72 return -ENODEV;73 74#define LM87_INT_TEMP 0x2775 76 /* Read temperature register */77 temp = wf_lm87_read_reg(lm->i2c, LM87_INT_TEMP);78 if (temp < 0)79 return temp;80 *value = temp << 16;81 82 return 0;83}84 85static void wf_lm87_release(struct wf_sensor *sr)86{87 struct wf_lm87_sensor *lm = wf_to_lm87(sr);88 89 kfree(lm);90}91 92static const struct wf_sensor_ops wf_lm87_ops = {93 .get_value = wf_lm87_get,94 .release = wf_lm87_release,95 .owner = THIS_MODULE,96};97 98static int wf_lm87_probe(struct i2c_client *client)99{ 100 struct wf_lm87_sensor *lm;101 const char *name = NULL, *loc;102 struct device_node *np = NULL;103 int rc;104 105 /*106 * The lm87 contains a whole pile of sensors, additionally,107 * the Xserve G5 has several lm87's. However, for now we only108 * care about the internal temperature sensor109 */110 for_each_child_of_node(client->dev.of_node, np) {111 if (!of_node_name_eq(np, "int-temp"))112 continue;113 loc = of_get_property(np, "location", NULL);114 if (!loc)115 continue;116 if (strstr(loc, "DIMM"))117 name = "dimms-temp";118 else if (strstr(loc, "Processors"))119 name = "between-cpus-temp";120 if (name) {121 of_node_put(np);122 break;123 }124 }125 if (!name) {126 pr_warn("wf_lm87: Unsupported sensor %pOF\n",127 client->dev.of_node);128 return -ENODEV;129 }130 131 lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);132 if (lm == NULL)133 return -ENODEV;134 135 lm->i2c = client;136 lm->sens.name = name;137 lm->sens.ops = &wf_lm87_ops;138 lm->sens.priv = lm;139 i2c_set_clientdata(client, lm);140 141 rc = wf_register_sensor(&lm->sens);142 if (rc)143 kfree(lm);144 return rc;145}146 147static void wf_lm87_remove(struct i2c_client *client)148{149 struct wf_lm87_sensor *lm = i2c_get_clientdata(client);150 151 /* Mark client detached */152 lm->i2c = NULL;153 154 /* release sensor */155 wf_unregister_sensor(&lm->sens);156}157 158static const struct i2c_device_id wf_lm87_id[] = {159 { "MAC,lm87cimt" },160 { }161};162MODULE_DEVICE_TABLE(i2c, wf_lm87_id);163 164static const struct of_device_id wf_lm87_of_id[] = {165 { .compatible = "lm87cimt", },166 { }167};168MODULE_DEVICE_TABLE(of, wf_lm87_of_id);169 170static struct i2c_driver wf_lm87_driver = {171 .driver = {172 .name = "wf_lm87",173 .of_match_table = wf_lm87_of_id,174 },175 .probe = wf_lm87_probe,176 .remove = wf_lm87_remove,177 .id_table = wf_lm87_id,178};179 180static int __init wf_lm87_sensor_init(void)181{182 /* We only support this on the Xserve */183 if (!of_machine_is_compatible("RackMac3,1"))184 return -ENODEV;185 186 return i2c_add_driver(&wf_lm87_driver);187}188 189static void __exit wf_lm87_sensor_exit(void)190{191 i2c_del_driver(&wf_lm87_driver);192}193 194 195module_init(wf_lm87_sensor_init);196module_exit(wf_lm87_sensor_exit);197 198MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");199MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");200MODULE_LICENSE("GPL");201 202