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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. The default exec_mipi_pmic_seq_element implementation from drivers/acpi/pmic/intel_pmic.c does a regmap_update_bits() call and the involved registers are typically marked as volatile in the regmap, so this leads to 2 I2C-bus accesses. Add a XPower AXP288 specific implementation of exec_mipi_pmic_seq_element which calls iosf_mbi_block_punit_i2c_access() calls before the regmap_update_bits() call to avoid having to do the whole expensive acquire P-Unit semaphore dance twice. 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> |
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| .. | ||
| intel_pmic.c | ||
| intel_pmic.h | ||
| intel_pmic_bxtwc.c | ||
| intel_pmic_bytcrc.c | ||
| intel_pmic_chtcrc.c | ||
| intel_pmic_chtdc_ti.c | ||
| intel_pmic_chtwc.c | ||
| intel_pmic_xpower.c | ||
| Kconfig | ||
| Makefile | ||
| tps68470_pmic.c | ||