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authorHans de Goede <hdegoede@redhat.com>2018-10-11 16:29:10 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-10-25 17:00:05 +0200
commit3c670dba864d9ab0a23612a93b7d98700734bd44 (patch)
tree1718fbc1c3f426f3da42d27abd5abfd7738bd7ac /drivers/acpi/pmic
parente09db3d241f8d594381b6e5f2ca0f72ffcce478a (diff)
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 <hdegoede@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/pmic')
-rw-r--r--drivers/acpi/pmic/intel_pmic_xpower.c21
1 files changed, 15 insertions, 6 deletions
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 <linux/acpi.h>
#include <linux/init.h>
#include <linux/mfd/axp20x.h>
-#include <linux/platform_device.h>
#include <linux/regmap.h>
+#include <linux/platform_device.h>
+#include <asm/iosf_mbi.h>
#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;
}
/**