![Jean Delvare](/assets/img/avatar_default.png)
If i2c device probing fails, then there is no driver to dereference after calling i2c_new_device(). Stop assuming that probing will always succeed, to avoid NULL pointer dereferences. We have an easier access to the driver anyway. Signed-off-by: Jean Delvare <khali@linux-fr.org> Tested-by: Tim Shepard <shep@alum.mit.edu> Cc: Colin Leroy <colin@colino.net>
262 lines
6 KiB
C
262 lines
6 KiB
C
/*
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* Windfarm PowerMac thermal control. LM75 sensor
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*
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* (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
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* <benh@kernel.crashing.org>
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*
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* Released under the term of the GNU GPL v2.
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*/
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/wait.h>
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#include <linux/i2c.h>
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#include <asm/prom.h>
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#include <asm/machdep.h>
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#include <asm/io.h>
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#include <asm/system.h>
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#include <asm/sections.h>
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#include <asm/pmac_low_i2c.h>
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#include "windfarm.h"
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#define VERSION "0.2"
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#undef DEBUG
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#ifdef DEBUG
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#define DBG(args...) printk(args)
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#else
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#define DBG(args...) do { } while(0)
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#endif
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struct wf_lm75_sensor {
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int ds1775 : 1;
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int inited : 1;
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struct i2c_client *i2c;
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struct wf_sensor sens;
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};
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#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
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static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
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{
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struct wf_lm75_sensor *lm = wf_to_lm75(sr);
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s32 data;
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if (lm->i2c == NULL)
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return -ENODEV;
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/* Init chip if necessary */
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if (!lm->inited) {
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u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
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DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
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sr->name, cfg);
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/* clear shutdown bit, keep other settings as left by
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* the firmware for now
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*/
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cfg_new = cfg & ~0x01;
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i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
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lm->inited = 1;
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/* If we just powered it up, let's wait 200 ms */
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msleep(200);
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}
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/* Read temperature register */
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data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
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data <<= 8;
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*value = data;
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return 0;
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}
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static void wf_lm75_release(struct wf_sensor *sr)
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{
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struct wf_lm75_sensor *lm = wf_to_lm75(sr);
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kfree(lm);
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}
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static struct wf_sensor_ops wf_lm75_ops = {
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.get_value = wf_lm75_get,
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.release = wf_lm75_release,
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.owner = THIS_MODULE,
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};
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static int wf_lm75_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct wf_lm75_sensor *lm;
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int rc;
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lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
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if (lm == NULL)
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return -ENODEV;
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lm->inited = 0;
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lm->ds1775 = id->driver_data;
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lm->i2c = client;
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lm->sens.name = client->dev.platform_data;
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lm->sens.ops = &wf_lm75_ops;
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i2c_set_clientdata(client, lm);
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rc = wf_register_sensor(&lm->sens);
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if (rc) {
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i2c_set_clientdata(client, NULL);
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kfree(lm);
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}
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return rc;
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}
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static struct i2c_driver wf_lm75_driver;
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static struct i2c_client *wf_lm75_create(struct i2c_adapter *adapter,
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u8 addr, int ds1775,
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const char *loc)
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{
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struct i2c_board_info info;
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struct i2c_client *client;
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char *name;
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DBG("wf_lm75: creating %s device at address 0x%02x\n",
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ds1775 ? "ds1775" : "lm75", addr);
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/* Usual rant about sensor names not beeing very consistent in
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* the device-tree, oh well ...
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* Add more entries below as you deal with more setups
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*/
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if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
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name = "hd-temp";
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else if (!strcmp(loc, "Incoming Air Temp"))
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name = "incoming-air-temp";
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else if (!strcmp(loc, "ODD Temp"))
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name = "optical-drive-temp";
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else if (!strcmp(loc, "HD Temp"))
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name = "hard-drive-temp";
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else
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goto fail;
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memset(&info, 0, sizeof(struct i2c_board_info));
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info.addr = (addr >> 1) & 0x7f;
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info.platform_data = name;
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strlcpy(info.type, ds1775 ? "wf_ds1775" : "wf_lm75", I2C_NAME_SIZE);
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client = i2c_new_device(adapter, &info);
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if (client == NULL) {
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printk(KERN_ERR "windfarm: failed to attach %s %s to i2c\n",
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ds1775 ? "ds1775" : "lm75", name);
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goto fail;
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}
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/*
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* Let i2c-core delete that device on driver removal.
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* This is safe because i2c-core holds the core_lock mutex for us.
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*/
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list_add_tail(&client->detected, &wf_lm75_driver.clients);
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return client;
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fail:
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return NULL;
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}
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static int wf_lm75_attach(struct i2c_adapter *adapter)
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{
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struct device_node *busnode, *dev;
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struct pmac_i2c_bus *bus;
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DBG("wf_lm75: adapter %s detected\n", adapter->name);
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bus = pmac_i2c_adapter_to_bus(adapter);
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if (bus == NULL)
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return -ENODEV;
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busnode = pmac_i2c_get_bus_node(bus);
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DBG("wf_lm75: bus found, looking for device...\n");
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/* Now look for lm75(s) in there */
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for (dev = NULL;
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(dev = of_get_next_child(busnode, dev)) != NULL;) {
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const char *loc =
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of_get_property(dev, "hwsensor-location", NULL);
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u8 addr;
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/* We must re-match the adapter in order to properly check
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* the channel on multibus setups
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*/
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if (!pmac_i2c_match_adapter(dev, adapter))
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continue;
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addr = pmac_i2c_get_dev_addr(dev);
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if (loc == NULL || addr == 0)
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continue;
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/* real lm75 */
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if (of_device_is_compatible(dev, "lm75"))
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wf_lm75_create(adapter, addr, 0, loc);
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/* ds1775 (compatible, better resolution */
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else if (of_device_is_compatible(dev, "ds1775"))
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wf_lm75_create(adapter, addr, 1, loc);
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}
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return 0;
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}
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static int wf_lm75_remove(struct i2c_client *client)
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{
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struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
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DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
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/* Mark client detached */
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lm->i2c = NULL;
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/* release sensor */
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wf_unregister_sensor(&lm->sens);
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i2c_set_clientdata(client, NULL);
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return 0;
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}
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static const struct i2c_device_id wf_lm75_id[] = {
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{ "wf_lm75", 0 },
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{ "wf_ds1775", 1 },
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{ }
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};
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static struct i2c_driver wf_lm75_driver = {
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.driver = {
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.name = "wf_lm75",
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},
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.attach_adapter = wf_lm75_attach,
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.probe = wf_lm75_probe,
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.remove = wf_lm75_remove,
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.id_table = wf_lm75_id,
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};
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static int __init wf_lm75_sensor_init(void)
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{
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/* Don't register on old machines that use therm_pm72 for now */
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if (machine_is_compatible("PowerMac7,2") ||
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machine_is_compatible("PowerMac7,3") ||
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machine_is_compatible("RackMac3,1"))
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return -ENODEV;
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return i2c_add_driver(&wf_lm75_driver);
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}
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static void __exit wf_lm75_sensor_exit(void)
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{
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i2c_del_driver(&wf_lm75_driver);
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}
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module_init(wf_lm75_sensor_init);
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module_exit(wf_lm75_sensor_exit);
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MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
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MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
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MODULE_LICENSE("GPL");
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