stm32mp1: update I2C and PMIC drivers

Regulator configuration at boot takes more information from DT.
I2C configuration from DT is done in I2C driver.
I2C driver manages more transfer modes.
The min voltage of buck1 should also be increased to 1.2V,
else the platform does not boot.

Heavily modifies stm32_i2c.c since many functions move inside the source
file to remove redundant declarations.

Change-Id: I0bee5d776cf3ff15e687427cd6abc06ab237d025
Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Nicolas LE BAYON <nicolas.le.bayon@st.com>
diff --git a/include/drivers/st/stm32mp_pmic.h b/include/drivers/st/stm32mp_pmic.h
index 700039b..984cd60 100644
--- a/include/drivers/st/stm32mp_pmic.h
+++ b/include/drivers/st/stm32mp_pmic.h
@@ -11,10 +11,41 @@
 
 #include <platform_def.h>
 
-bool dt_check_pmic(void);
-int dt_pmic_enable_boot_on_regulators(void);
-void initialize_pmic_i2c(void);
+/*
+ * dt_pmic_status - Check PMIC status from device tree
+ *
+ * Returns the status of the PMIC (secure, non-secure), or a negative value on
+ * error
+ */
+int dt_pmic_status(void);
+
+/*
+ * dt_pmic_configure_boot_on_regulators - Configure boot-on and always-on
+ * regulators from device tree configuration
+ *
+ * Returns 0 on success, and negative values on errors
+ */
+int dt_pmic_configure_boot_on_regulators(void);
+
+/*
+ * initialize_pmic_i2c - Initialize I2C for the PMIC control
+ *
+ * Returns true if PMIC is available, false if not found, panics on errors
+ */
+bool initialize_pmic_i2c(void);
+
+/*
+ * initialize_pmic - Main PMIC initialization function, called at platform init
+ *
+ * Panics on errors
+ */
 void initialize_pmic(void);
+
+/*
+ * pmic_ddr_power_init - Initialize regulators required for DDR
+ *
+ * Returns 0 on success, and negative values on errors
+ */
 int pmic_ddr_power_init(enum ddr_type ddr_type);
 
 #endif /* STM32MP_PMIC_H */