From 3c670dba864d9ab0a23612a93b7d98700734bd44 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 11 Oct 2018 16:29:10 +0200 Subject: ACPI / PMIC: xpower: Block P-Unit I2C access during read-modify-write intel_xpower_pmic_update_power() does a read-modify-write of the output control register. The i2c-designware code blocks the P-Unit I2C access during the read and write by taking the P-Unit's PMIC bus semaphore. But between the read and the write that semaphore is released and the P-Unit could make changes to the register which we then end up overwriting. This commit makes intel_xpower_pmic_update_power() take the semaphore itself so that it is held over the entire read-modify-write, avoiding this race. Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- drivers/acpi/pmic/intel_pmic_xpower.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) (limited to 'drivers') diff --git a/drivers/acpi/pmic/intel_pmic_xpower.c b/drivers/acpi/pmic/intel_pmic_xpower.c index aadc86db804c..2579675b7082 100644 --- a/drivers/acpi/pmic/intel_pmic_xpower.c +++ b/drivers/acpi/pmic/intel_pmic_xpower.c @@ -8,8 +8,9 @@ #include #include #include -#include #include +#include +#include #include "intel_pmic.h" #define XPOWER_GPADC_LOW 0x5b @@ -172,15 +173,21 @@ static int intel_xpower_pmic_get_power(struct regmap *regmap, int reg, static int intel_xpower_pmic_update_power(struct regmap *regmap, int reg, int bit, bool on) { - int data; + int data, ret; /* GPIO1 LDO regulator needs special handling */ if (reg == XPOWER_GPI1_CTRL) return regmap_update_bits(regmap, reg, GPI1_LDO_MASK, on ? GPI1_LDO_ON : GPI1_LDO_OFF); - if (regmap_read(regmap, reg, &data)) - return -EIO; + ret = iosf_mbi_block_punit_i2c_access(); + if (ret) + return ret; + + if (regmap_read(regmap, reg, &data)) { + ret = -EIO; + goto out; + } if (on) data |= BIT(bit); @@ -188,9 +195,11 @@ static int intel_xpower_pmic_update_power(struct regmap *regmap, int reg, data &= ~BIT(bit); if (regmap_write(regmap, reg, data)) - return -EIO; + ret = -EIO; +out: + iosf_mbi_unblock_punit_i2c_access(); - return 0; + return ret; } /** -- cgit v1.2.3