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| author | Hans de Goede <hdegoede@redhat.com> | 2021-07-06 18:09:22 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-07-16 19:05:59 +0200 |
| commit | e38ba404f20c4beb1a5d4547567d2934a5b95843 (patch) | |
| tree | e730709e0e8357ddf3264ef587b778cc873cebf0 /drivers/acpi | |
| parent | e73f0f0ee7541171d89f2e2491130c7771ba58d3 (diff) | |
| download | linux-e38ba404f20c4beb1a5d4547567d2934a5b95843.tar.bz2 | |
ACPI / PMIC: XPower: optimize I2C-bus accesses
The I2C-bus to the XPower AXP288 is shared between the Linux kernel and
the SoCs P-Unit. The P-Unit has a semaphore which the kernel must "lock"
before it may use the bus and while the kernel holds the semaphore the CPU
and GPU power-states must not be changed otherwise the system will freeze.
This is a complex process, which is quite expensive. This is all done by
iosf_mbi_block_punit_i2c_access(). To ensure that no unguarded I2C-bus
accesses happen, iosf_mbi_block_punit_i2c_access() gets called by the
I2C-bus-driver for every I2C transfer. Because this is so expensive it
is allowed to call iosf_mbi_block_punit_i2c_access() in a nested
fashion, so that higher-level code which does multiple I2C-transfers can
call it once for a group of transfers, turning the calls done by the
I2C-bus-driver into no-ops.
Add iosf_mbi_block_punit_i2c_access() calls around groups of register
accesses, so that the P-Unit semaphore only needs to be taken once
for each group of register accesses.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
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')
| -rw-r--r-- | drivers/acpi/pmic/intel_pmic_xpower.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/drivers/acpi/pmic/intel_pmic_xpower.c b/drivers/acpi/pmic/intel_pmic_xpower.c index a091d5a8392c..5750c5e7d4c6 100644 --- a/drivers/acpi/pmic/intel_pmic_xpower.c +++ b/drivers/acpi/pmic/intel_pmic_xpower.c @@ -178,15 +178,17 @@ static int intel_xpower_pmic_update_power(struct regmap *regmap, int reg, { 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); - ret = iosf_mbi_block_punit_i2c_access(); if (ret) return ret; + /* GPIO1 LDO regulator needs special handling */ + if (reg == XPOWER_GPI1_CTRL) { + ret = regmap_update_bits(regmap, reg, GPI1_LDO_MASK, + on ? GPI1_LDO_ON : GPI1_LDO_OFF); + goto out; + } + if (regmap_read(regmap, reg, &data)) { ret = -EIO; goto out; @@ -234,6 +236,11 @@ static int intel_xpower_pmic_get_raw_temp(struct regmap *regmap, int reg) return ret; if (adc_ts_pin_ctrl & AXP288_ADC_TS_CURRENT_ON_OFF_MASK) { + /* + * AXP288_ADC_TS_PIN_CTRL reads are cached by the regmap, so + * this does to a single I2C-transfer, and thus there is no + * need to explicitly call iosf_mbi_block_punit_i2c_access(). + */ ret = regmap_update_bits(regmap, AXP288_ADC_TS_PIN_CTRL, AXP288_ADC_TS_CURRENT_ON_OFF_MASK, AXP288_ADC_TS_CURRENT_ON_ONDEMAND); @@ -244,6 +251,10 @@ static int intel_xpower_pmic_get_raw_temp(struct regmap *regmap, int reg) usleep_range(6000, 10000); } + ret = iosf_mbi_block_punit_i2c_access(); + if (ret) + return ret; + ret = regmap_bulk_read(regmap, AXP288_GP_ADC_H, buf, 2); if (ret == 0) ret = (buf[0] << 4) + ((buf[1] >> 4) & 0x0f); @@ -254,6 +265,8 @@ static int intel_xpower_pmic_get_raw_temp(struct regmap *regmap, int reg) AXP288_ADC_TS_CURRENT_ON); } + iosf_mbi_unblock_punit_i2c_access(); + return ret; } |