hwmon: (lm92) Prevent overflow problem when writing large limits
On platforms with sizeof(int) < sizeof(long), writing a temperature limit larger than MAXINT will result in unpredictable limit values written to the chip. Avoid auto-conversion from long to int to fix the problem. The hysteresis temperature range depends on the value of data->temp[attr->index], since val is subtracted from it. Use a wider clamp, [-120000, 220000] should do to cover the possible range. Also add missing TEMP_TO_REG() on writes into cached hysteresis value. Also uses clamp_val to simplify the code a bit. Signed-off-by: Axel Lin <axel.lin@ingics.com> [Guenter Roeck: Fixed double TEMP_TO_REG on hysteresis updates] Cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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@ -74,12 +74,9 @@ static inline int TEMP_FROM_REG(s16 reg)
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return reg / 8 * 625 / 10;
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}
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static inline s16 TEMP_TO_REG(int val)
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static inline s16 TEMP_TO_REG(long val)
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{
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if (val <= -60000)
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return -60000 * 10 / 625 * 8;
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if (val >= 160000)
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return 160000 * 10 / 625 * 8;
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val = clamp_val(val, -60000, 160000);
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return val * 10 / 625 * 8;
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}
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@ -206,10 +203,12 @@ static ssize_t set_temp_hyst(struct device *dev,
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if (err)
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return err;
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val = clamp_val(val, -120000, 220000);
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mutex_lock(&data->update_lock);
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data->temp[t_hyst] = TEMP_FROM_REG(data->temp[attr->index]) - val;
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data->temp[t_hyst] =
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TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
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i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
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TEMP_TO_REG(data->temp[t_hyst]));
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data->temp[t_hyst]);
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mutex_unlock(&data->update_lock);
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return count;
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}
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