Re: [PATCH v2 01/10] clk: sunxi-ng: Add interface to query or configure MMC timing modes.

Maxime Ripard
2017-07-21T07:18:10Z

[-- Attachment #1: Type: text/plain, Size: 2677 bytes --]

Hi,

On Thu, Jul 20, 2017 at 11:44:43AM +0800, Chen-Yu Tsai wrote:
> Starting with the A83T SoC, Allwinner introduced a new timing mode for
> its MMC clocks. The new mode changes how the MMC controller sample and
> output clocks are delayed to match chip and board specifics. There are
> two controls for this, one on the CCU side controlling how the clocks
> behave, and one in the MMC controller controlling what inputs to take
> and how to route them.
>
> In the old mode, the MMC clock had 2 child clocks providing the output
> and sample clocks, which could be delayed by a number of clock cycles
> measured from the MMC clock's parent.
>
> With the new mode, the 2 delay clocks are no longer active. Instead,
> the delays and associated controls are moved into the MMC controller.
> The output of the MMC clock is also halved.
>
> The difference in how things are wired between the modes means that the
> clock controls and the MMC controls must match. To achieve this in a
> clear, explicit way, we introduce two functions for the MMC driver to
> use: one queries the hardware for the current mode set, and the other
> allows the MMC driver to request a mode.
>
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
> drivers/clk/sunxi-ng/Makefile | 1 +
> drivers/clk/sunxi-ng/ccu_common.h | 5 +++
> drivers/clk/sunxi-ng/ccu_mmc_timing.c | 73 +++++++++++++++++++++++++++++++++++
> include/linux/clk/sunxi-ng.h | 35 +++++++++++++++++
> 4 files changed, 114 insertions(+)
> create mode 100644 drivers/clk/sunxi-ng/ccu_mmc_timing.c
> create mode 100644 include/linux/clk/sunxi-ng.h
>
> diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
> index 0c45fa50283d..45a5910379a5 100644
> --- a/drivers/clk/sunxi-ng/Makefile
> +++ b/drivers/clk/sunxi-ng/Makefile
> @@ -1,5 +1,6 @@
> # Common objects
> lib-$(CONFIG_SUNXI_CCU) += ccu_common.o
> +lib-$(CONFIG_SUNXI_CCU) += ccu_mmc_timing.o
> lib-$(CONFIG_SUNXI_CCU) += ccu_reset.o
>
> # Base clock types
> diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h
> index d6fdd7a789aa..1e2761c53f06 100644
> --- a/drivers/clk/sunxi-ng/ccu_common.h
> +++ b/drivers/clk/sunxi-ng/ccu_common.h
> @@ -23,6 +23,11 @@
> #define CCU_FEATURE_FIXED_POSTDIV BIT(3)
> #define CCU_FEATURE_ALL_PREDIV BIT(4)
> #define CCU_FEATURE_LOCK_REG BIT(5)
> +#define CCU_FEATURE_MMC_TIMING_SWITCH BIT(6)
> +#define CCU_FEATURE_MMC_ALWAYS_NEW BIT(7)

Didn't we agree on removing that flag?

Maxime

--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 801 bytes --]