From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Chen-Yu Tsai <wens@csie.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org,
linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [PATCH v2 01/10] clk: sunxi-ng: Add interface to query or configure MMC timing modes.
Date: Fri, 21 Jul 2017 09:18:10 +0200 [thread overview]
Message-ID: <20170721071810.7nlwdzqno56cdax3@flea> (raw)
In-Reply-To: <20170720034452.15920-2-wens@csie.org>
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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 With the new mode, the 2 delay clocks are no longer active.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
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next prev parent reply other threads:[~2017-07-21 7:18 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 3:44 [PATCH v2 00/10] ARM: sun8i: a83t: Add support for MMC controllers Chen-Yu Tsai
2017-07-20 3:44 ` [PATCH v2 01/10] clk: sunxi-ng: Add interface to query or configure MMC timing modes Chen-Yu Tsai
2017-07-21 7:18 ` Maxime Ripard [this message]
2017-07-21 7:23 ` Chen-Yu Tsai
2017-07-20 3:44 ` [PATCH v2 02/10] clk: sunxi-ng: Add MP_MMC clocks that support MMC timing modes switching Chen-Yu Tsai
2017-07-21 7:19 ` Maxime Ripard
2017-07-20 3:44 ` [PATCH v2 03/10] clk: sunxi-ng: a83t: Support new timing mode for mmc2 clock Chen-Yu Tsai
2017-07-20 3:44 ` [PATCH v2 04/10] mmc: sunxi: Support controllers that can use both old and new timings Chen-Yu Tsai
2017-07-21 7:20 ` Maxime Ripard
2017-07-20 3:44 ` [PATCH v2 05/10] mmc: sunxi: Support MMC DDR52 transfer mode with new timing mode Chen-Yu Tsai
2017-07-21 7:21 ` Maxime Ripard
2017-07-20 3:44 ` [PATCH v2 06/10] mmc: sunxi: Add support for A83T eMMC (MMC2) Chen-Yu Tsai
2017-07-21 7:21 ` Maxime Ripard
2017-07-20 3:44 ` [PATCH v2 07/10] ARM: dts: sun8i: a83t: Add MMC controller device nodes Chen-Yu Tsai
2017-07-23 0:36 ` kbuild test robot
2017-07-20 3:44 ` [PATCH v2 08/10] ARM: dts: sun8i: a83t: Add pingroup for 8-bit eMMC on mmc2 Chen-Yu Tsai
2017-07-20 3:44 ` [PATCH v2 09/10] ARM: dts: sun8i: a83t: cubietruck-plus: Enable micro-SD card and eMMC Chen-Yu Tsai
2017-07-20 3:44 ` [PATCH v2 10/10] ARM: dts: sun8i: a83t: h8homlet: Enable micro-SD card and onboard eMMC Chen-Yu Tsai
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