Re: [PATCH 04/10] mmc: Add invert flag for clock phase signedness
From: Andrew Jeffery <hidden>
Date: 2021-10-26 00:53:13
Also in:
linux-arm-kernel, linux-aspeed, linux-clk, linux-mmc, lkml, openbmc
On Wed, 22 Sep 2021, at 20:01, Chin-Ting Kuo wrote:
The clock phase degree may be between -360 to 360. If the data signal is leading to the clock, the signedness of clock phase is postive, otherwise, the signedness is negative. Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
The implementation here can't be changed without a change to the binding documentation: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/mmc/mmc-controller.yaml?h=v5.15-rc7#n345
quoted hunk ↗ jump to hunk
--- drivers/mmc/core/host.c | 10 ++++++---- include/linux/mmc/host.h | 2 ++ 2 files changed, 8 insertions(+), 4 deletions(-)diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index d4683b1d263f..c2de7cbc7838 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c@@ -214,14 +214,16 @@ static void mmc_retune_timer(struct timer_list *t) static void mmc_of_parse_timing_phase(struct device *dev, const char *prop, struct mmc_clk_phase *phase) { - int degrees[2] = {0}; + int degrees[4] = {0}; int rc; - rc = device_property_read_u32_array(dev, prop, degrees, 2); + rc = device_property_read_u32_array(dev, prop, degrees, 4); phase->valid = !rc; if (phase->valid) { - phase->in_deg = degrees[0]; - phase->out_deg = degrees[1]; + phase->inv_in_deg = degrees[0] ? true : false; + phase->in_deg = degrees[1]; + phase->inv_out_deg = degrees[2] ? true : false; + phase->out_deg = degrees[3];
This fundamentally breaks any in-tree users. We can't do this. In terms of the binding, if negative phase values are something we must do, we can just extend the value range to include [-359, -1] right? That avoids changing the type of the value positions in the manner this patch does. Andrew