board: verdin-am62: set cpu core voltage depending on speed grade
Speed grade T requires the VDD_CORE voltage to be 0.85V if using
the maximum core frequency.
Speed grades G, K, S allow the VDD_CORE voltage to be 0.75V up to the
maximum core frequency but allow to run at 0.85V.
For efficiency in manufacturing and code maintenance we use 0.85V for
the PMIC defaults and device tree settings and dynamically adjust the
voltage in the PMIC and device tree to 0.75V for lower speed SKU to
gain more than 100mW power consumption reduction.
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
diff --git a/board/toradex/verdin-am62/verdin-am62.c b/board/toradex/verdin-am62/verdin-am62.c
index e948fc1..395eb36 100644
--- a/board/toradex/verdin-am62/verdin-am62.c
+++ b/board/toradex/verdin-am62/verdin-am62.c
@@ -14,10 +14,13 @@
#include <fdt_support.h>
#include <init.h>
#include <k3-ddrss.h>
+#include <power/regulator.h>
#include <spl.h>
#include "../common/tdx-cfg-block.h"
+#define VDD_CORE_REG "buck1"
+
DECLARE_GLOBAL_DATA_PTR;
int board_init(void)
@@ -50,9 +53,37 @@
}
#endif
+static u32 get_vdd_core_nominal(void)
+{
+ int core_uvolt;
+
+ switch (k3_get_speed_grade()) {
+ case 'G':
+ case 'K':
+ case 'S':
+ core_uvolt = 750000;
+ break;
+ case 'T':
+ default:
+ core_uvolt = 850000;
+ break;
+ }
+ return core_uvolt;
+}
+
#if IS_ENABLED(CONFIG_OF_LIBFDT) && IS_ENABLED(CONFIG_OF_BOARD_SETUP)
int ft_board_setup(void *blob, struct bd_info *bd)
{
+ int core_uvolt;
+
+ core_uvolt = get_vdd_core_nominal();
+ if (core_uvolt != 850000) {
+ do_fixup_by_path_u32(blob, "/bus@f0000/i2c@20000000/pmic@30/regulators/buck1",
+ "regulator-max-microvolt", core_uvolt, 0);
+ do_fixup_by_path_u32(blob, "/bus@f0000/i2c@20000000/pmic@30/regulators/buck1",
+ "regulator-min-microvolt", core_uvolt, 0);
+ }
+
return ft_common_board_setup(blob, bd);
}
#endif
@@ -87,6 +118,22 @@
int board_late_init(void)
{
+ int ret;
+ int core_uvolt;
+ struct udevice *dev = NULL;
+
+ core_uvolt = get_vdd_core_nominal();
+ if (core_uvolt != 850000) {
+ /* Set CPU core voltage to 0.75V for slower speed grades */
+ ret = regulator_get_by_devname(VDD_CORE_REG, &dev);
+ if (ret)
+ pr_err("VDD CORE Regulator get error: %d\n", ret);
+
+ ret = regulator_set_value_force(dev, core_uvolt);
+ if (ret)
+ pr_err("VDD CORE Regulator value setting error: %d\n", ret);
+ }
+
select_dt_from_module_version();
return 0;