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| author | Leonard Crestez <leonard.crestez@nxp.com> | 2019-11-22 22:45:03 +0100 |
|---|---|---|
| committer | Chanwoo Choi <cw00.choi@samsung.com> | 2019-12-30 01:59:05 +0100 |
| commit | 5af744ebae856a50e8b5e208a5acf28713a4ce98 (patch) | |
| tree | 26f1fc739896b4503768c1062756ce219e786034 /drivers/devfreq/Makefile | |
| parent | dt-bindings: memory: Add bindings for imx8m ddr controller (diff) | |
| download | linux-5af744ebae856a50e8b5e208a5acf28713a4ce98.tar.xz linux-5af744ebae856a50e8b5e208a5acf28713a4ce98.zip | |
PM / devfreq: Add dynamic scaling for imx8m ddr controller
Add driver for dynamic scaling the DDR Controller on imx8m chips. Actual
frequency switching is implemented inside TF-A, this driver wraps the
SMC calls and synchronizes the clk tree.
The DRAM clocks on imx8m have the following structure (abridged):
+----------+ |\ +------+
| dram_pll |-------|M| dram_core | |
+----------+ |U|---------->| D |
/--|X| | D |
dram_alt_root | |/ | R |
| | C |
+---------+ | |
|FIX DIV/4| | |
+---------+ | |
composite: | | |
+----------+ | | |
| dram_alt |----/ | |
+----------+ | |
| dram_apb |-------------------->| |
+----------+ +------+
The dram_pll is used for higher rates and dram_alt is used for lower
rates. The dram_alt and dram_apb clocks are "imx composite" and their
parent can also be modified.
This driver will prepare/enable the new parents ahead of switching (so
that the expected roots are enabled) and afterwards it will call
clk_set_parent to ensure the parents in clock framework are up-to-date.
The driver relies on dram_pll dram_alt and dram_apb being marked with
CLK_GET_RATE_NOCACHE for rate updates.
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
[cw00.choi: Edit the COMPILE_TEST module dependency in Kconfig]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Diffstat (limited to 'drivers/devfreq/Makefile')
| -rw-r--r-- | drivers/devfreq/Makefile | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile index 338ae8440db6..3eb4d5e6635c 100644 --- a/drivers/devfreq/Makefile +++ b/drivers/devfreq/Makefile @@ -9,6 +9,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o # DEVFREQ Drivers obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o +obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o obj-$(CONFIG_ARM_TEGRA20_DEVFREQ) += tegra20-devfreq.o |