Commit 1f6b5390 authored Jul 25, 2017 by Alexander Dahl Committed by Alexandre Belloni Jul 26, 2017

memory: atmel-ebi: Allow t_DF timings of zero ns

As reported in [1] and in [2] it's not possible to set the device tree
property 'atmel,smc-tdf-ns' to zero, although the SoC allows a setting
of 0ns for the t_DF time.

Allow this setting by doing the same thing as in the atmel nand
controller driver by setting ncycles to ATMEL_SMC_MODE_TDF_MIN if zero
is set in the dts.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-March/490966.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-July/520652.html



Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexander Dahl <ada@thorsis.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

parent bc9b934b

drivers/memory/atmel-ebi.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -120,12 +120,14 @@ static int atmel_ebi_xslate_smc_timings(struct atmel_ebi_dev *ebid,
	if (!ret) {		if (!ret) {
	required = true;		required = true;
	ncycles = DIV_ROUND_UP(val, clk_period_ns);		ncycles = DIV_ROUND_UP(val, clk_period_ns);
	if (ncycles > ATMEL_SMC_MODE_TDF_MAX \|\|		if (ncycles > ATMEL_SMC_MODE_TDF_MAX) {
	ncycles < ATMEL_SMC_MODE_TDF_MIN) {
	ret = -EINVAL;		ret = -EINVAL;
	goto out;		goto out;
	}		}

			if (ncycles < ATMEL_SMC_MODE_TDF_MIN)
			ncycles = ATMEL_SMC_MODE_TDF_MIN;

	smcconf->mode \|= ATMEL_SMC_MODE_TDF(ncycles);		smcconf->mode \|= ATMEL_SMC_MODE_TDF(ncycles);
	}		}