From: Vignesh R <vigneshr@ti.com>
To: "Tudor.Ambarus@microchip.com" <Tudor.Ambarus@microchip.com>,
"bbrezillon@kernel.org" <bbrezillon@kernel.org>
Cc: "marek.vasut@gmail.com" <marek.vasut@gmail.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] mtd: spi-nor: cadence-quadspi: Add support for Octal SPI controller
Date: Mon, 21 Jan 2019 11:30:57 +0530 [thread overview]
Message-ID: <de9f281c-6bbb-2686-a809-f53302d1a3e0@ti.com> (raw)
In-Reply-To: <353a011e-920a-ddb3-4eef-e3256555ac93@microchip.com>
On 20/01/19 8:58 PM, Tudor.Ambarus@microchip.com wrote:
> Vignesh,
>
> On 01/20/2019 04:56 PM, Tudor.Ambarus@microchip.com wrote:
>> Looks good.
>
> one more thing: in cqspi_read_setup() I see that the dummy cycles are adjusted
> if (f_pdata->inst_width != CQSPI_INST_TYPE_QUAD).
>
> Should you adjust the dummy cycles for octo too?
Driver does not claim support for SNOR_HWCAPS_PP_4_4_4 mode or
SNOR_HWCAPS_PP_8_8_8 mode. Therefore inst_width is always be
CQSPI_INST_TYPE_SINGLE (cqspi_set_protocol() always sets inst_width and
addr_width to CQSPI_INST_TYPE_SINGLE).
Code to support 4_4_4 or 8_8_8 mode is incomplete in the driver. Also,
using mode bits to satisfy dummy clk cycles does not seem right. My
guess is driver is broken, if inst_width is indeed CQSPI_INST_TYPE_QUAD
as we end up sending additional 8 dummy clock cycles over what is asked
in nor->read_dummy.
I will plan to fix these as part of moving driver over to spi-mem. But
above code should not impact 1-1-8 mode support.
> I tried to find a datasheet for the controller, without success though ...
>
You can find Octal SPI controller datasheet in AM65x SoC TRM here:
http://www.ti.com/lit/ug/spruid7b/spruid7b.pdf
Page 9449: 12.3.2 Octal Serial Peripheral Interface (OSPI)
--
Regards
Vignesh
WARNING: multiple messages have this Message-ID (diff)
From: Vignesh R <vigneshr@ti.com>
To: "Tudor.Ambarus@microchip.com" <Tudor.Ambarus@microchip.com>,
"bbrezillon@kernel.org" <bbrezillon@kernel.org>
Cc: "marek.vasut@gmail.com" <marek.vasut@gmail.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] mtd: spi-nor: cadence-quadspi: Add support for Octal SPI controller
Date: Mon, 21 Jan 2019 11:30:57 +0530 [thread overview]
Message-ID: <de9f281c-6bbb-2686-a809-f53302d1a3e0@ti.com> (raw)
In-Reply-To: <353a011e-920a-ddb3-4eef-e3256555ac93@microchip.com>
On 20/01/19 8:58 PM, Tudor.Ambarus@microchip.com wrote:
> Vignesh,
>
> On 01/20/2019 04:56 PM, Tudor.Ambarus@microchip.com wrote:
>> Looks good.
>
> one more thing: in cqspi_read_setup() I see that the dummy cycles are adjusted
> if (f_pdata->inst_width != CQSPI_INST_TYPE_QUAD).
>
> Should you adjust the dummy cycles for octo too?
Driver does not claim support for SNOR_HWCAPS_PP_4_4_4 mode or
SNOR_HWCAPS_PP_8_8_8 mode. Therefore inst_width is always be
CQSPI_INST_TYPE_SINGLE (cqspi_set_protocol() always sets inst_width and
addr_width to CQSPI_INST_TYPE_SINGLE).
Code to support 4_4_4 or 8_8_8 mode is incomplete in the driver. Also,
using mode bits to satisfy dummy clk cycles does not seem right. My
guess is driver is broken, if inst_width is indeed CQSPI_INST_TYPE_QUAD
as we end up sending additional 8 dummy clock cycles over what is asked
in nor->read_dummy.
I will plan to fix these as part of moving driver over to spi-mem. But
above code should not impact 1-1-8 mode support.
> I tried to find a datasheet for the controller, without success though ...
>
You can find Octal SPI controller datasheet in AM65x SoC TRM here:
http://www.ti.com/lit/ug/spruid7b/spruid7b.pdf
Page 9449: 12.3.2 Octal Serial Peripheral Interface (OSPI)
--
Regards
Vignesh
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http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-01-21 8:01 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-16 10:30 [PATCH v3 0/2] cadence-quadspi: Add Octal mode support Vignesh R
2019-01-16 10:30 ` Vignesh R
2019-01-16 10:30 ` Vignesh R
2019-01-16 10:30 ` [PATCH v3 1/2] dt-bindings: cadence-quadspi: Add new compatible for AM654 SoC Vignesh R
2019-01-16 10:30 ` Vignesh R
2019-01-16 10:30 ` Vignesh R
2019-01-16 10:30 ` [PATCH v3 2/2] mtd: spi-nor: cadence-quadspi: Add support for Octal SPI controller Vignesh R
2019-01-16 10:30 ` Vignesh R
2019-01-16 10:30 ` Vignesh R
2019-01-20 14:56 ` Tudor.Ambarus
2019-01-20 14:56 ` Tudor.Ambarus
2019-01-20 14:56 ` Tudor.Ambarus
2019-01-20 15:28 ` Tudor.Ambarus
2019-01-20 15:28 ` Tudor.Ambarus
2019-01-20 15:28 ` Tudor.Ambarus
2019-01-21 6:00 ` Vignesh R [this message]
2019-01-21 6:00 ` Vignesh R
2019-01-21 5:58 ` Vignesh R
2019-01-21 5:58 ` Vignesh R
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