From: Alexander Dahl <ada@thorsis.com> To: linux-arm-kernel@lists.infradead.org Cc: Boris Brezillon <boris.brezillon@free-electrons.com>, Samuel Ortiz <sameo@linux.intel.com>, Nicolas Ferre <nicolas.ferre@atmel.com>, linux-kernel@vger.kernel.org, Alexandre Belloni <alexandre.belloni@free-electrons.com>, Lee Jones <lee.jones@linaro.org> Subject: Re: [PATCH 2/7] memory: atmel-ebi: Simplify SMC config code Date: Tue, 25 Jul 2017 13:43:12 +0200 [thread overview] Message-ID: <1532488.qfy0e7fcKK@ada> (raw) In-Reply-To: <20170724212109.586e3512@bbrezillon> Hello Boris, Am Montag, 24. Juli 2017, 21:21:09 schrieb Boris Brezillon: > There is a good reason for this "- 1": the doc says the exact number > of tDF cycles is TDF_CYCLES + 1. When you are expressing timings in > ns it does matter, because you don't want to wait more than > necessary. Say the master clk period is X ns and you want a tDF of X > ns. If you divide tDF_ns by the clk period you get one, and you only > want to wait 1 cycle, not two. This makes sense. I tried several values through the same algorithm with a small test program and it gives the expected results. Thanks for the explanation. :-) > The NAND driver seems to do the right thing already [1]. > > Below is my suggestion below to fix the problem. Did you have > something else in mind? In any case, can you send a patch to fix it > (either using my suggestion or something else if you prefer). I prepared a small patch series together with two other small fixes for the atmel ebi driver and will send it to the list in a minute. Greets Alex
WARNING: multiple messages have this Message-ID (diff)
From: ada@thorsis.com (Alexander Dahl) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/7] memory: atmel-ebi: Simplify SMC config code Date: Tue, 25 Jul 2017 13:43:12 +0200 [thread overview] Message-ID: <1532488.qfy0e7fcKK@ada> (raw) In-Reply-To: <20170724212109.586e3512@bbrezillon> Hello Boris, Am Montag, 24. Juli 2017, 21:21:09 schrieb Boris Brezillon: > There is a good reason for this "- 1": the doc says the exact number > of tDF cycles is TDF_CYCLES + 1. When you are expressing timings in > ns it does matter, because you don't want to wait more than > necessary. Say the master clk period is X ns and you want a tDF of X > ns. If you divide tDF_ns by the clk period you get one, and you only > want to wait 1 cycle, not two. This makes sense. I tried several values through the same algorithm with a small test program and it gives the expected results. Thanks for the explanation. :-) > The NAND driver seems to do the right thing already [1]. > > Below is my suggestion below to fix the problem. Did you have > something else in mind? In any case, can you send a patch to fix it > (either using my suggestion or something else if you prefer). I prepared a small patch series together with two other small fixes for the atmel ebi driver and will send it to the list in a minute. Greets Alex
next prev parent reply other threads:[~2017-07-25 11:43 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-02-20 16:54 [PATCH 0/7] memory: atmel-ebi: Add PM ops Boris Brezillon 2017-02-20 16:54 ` Boris Brezillon 2017-02-20 16:54 ` [PATCH 1/7] mfd: syscon: atmel-smc: Add new helpers to ease SMC regs manipulation Boris Brezillon 2017-02-20 16:54 ` Boris Brezillon 2017-03-14 17:00 ` Lee Jones 2017-03-14 17:00 ` Lee Jones 2017-03-14 17:21 ` Boris Brezillon 2017-03-14 17:21 ` Boris Brezillon 2017-03-15 12:19 ` Lee Jones 2017-03-15 12:19 ` Lee Jones 2017-03-15 13:21 ` Boris Brezillon 2017-03-15 13:21 ` Boris Brezillon 2017-02-20 16:54 ` [PATCH 2/7] memory: atmel-ebi: Simplify SMC config code Boris Brezillon 2017-02-20 16:54 ` Boris Brezillon 2017-03-02 12:02 ` Alexander Dahl 2017-03-02 12:02 ` Alexander Dahl 2017-03-02 12:30 ` Boris Brezillon 2017-03-02 12:30 ` Boris Brezillon 2017-07-24 9:12 ` Alexander Dahl 2017-07-24 9:12 ` Alexander Dahl 2017-07-24 19:21 ` Boris Brezillon 2017-07-24 19:21 ` Boris Brezillon 2017-07-25 11:43 ` Alexander Dahl [this message] 2017-07-25 11:43 ` Alexander Dahl 2017-02-20 16:54 ` [PATCH 3/7] memory: atmel-ebi: Stop using reg_field objects for simple things Boris Brezillon 2017-02-20 16:54 ` Boris Brezillon 2017-02-20 16:54 ` [PATCH 4/7] mfd: syscon: atmel-smc: Remove unused helpers/macros Boris Brezillon 2017-02-20 16:54 ` Boris Brezillon 2017-02-20 16:54 ` [PATCH 5/7] memory: atmel-ebi: Change naming scheme Boris Brezillon 2017-02-20 16:54 ` Boris Brezillon 2017-02-20 16:55 ` [PATCH 6/7] memory: atmel-ebi: Add missing ->numcs assignment Boris Brezillon 2017-02-20 16:55 ` Boris Brezillon 2017-02-20 16:55 ` [PATCH 7/7] memory: atmel-ebi: Add PM ops Boris Brezillon 2017-02-20 16:55 ` Boris Brezillon
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