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Date: Thu, 17 Mar 2022 10:33:48 +0100 From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com> To: Leilk Liu <leilk.liu@...iatek.com>, Mark Brown <broonie@...nel.org> Cc: Rob Herring <robh+dt@...nel.org>, Matthias Brugger <matthias.bgg@...il.com>, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-spi@...r.kernel.org, linux-mediatek@...ts.infradead.org Subject: Re: [PATCH V4 4/6] spi: mediatek: add spi memory support for ipm design Il 17/03/22 10:27, Leilk Liu ha scritto: > On Tue, 2022-03-15 at 10:31 +0100, AngeloGioacchino Del Regno wrote: >> Il 15/03/22 04:24, Leilk Liu ha scritto: >>> this patch add the support of spi-mem for ipm design. >>> >>> Signed-off-by: Leilk Liu <leilk.liu@...iatek.com> >>> --- >>> drivers/spi/spi-mt65xx.c | 349 >>> ++++++++++++++++++++++++++++++++++++++- >>> 1 file changed, 348 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c >>> index 1a0b3208dfca..8958c3fa4fea 100644 >>> --- a/drivers/spi/spi-mt65xx.c >>> +++ b/drivers/spi/spi-mt65xx.c >> >> ...snip... >> >>> + >>> +static void of_mtk_spi_parse_dt(struct spi_master *master, struct >>> device_node *nc) >>> +{ >>> + struct mtk_spi *mdata = spi_master_get_devdata(master); >>> + u32 value; >>> + >>> + if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { >> >> Hello Leilk, >> >> thanks for considering my advice about "spi-{tx,rx}-bus-width", but >> there's >> something that you have misunderstood about it. >> >> Simply, you don't need this function at all. Whatever you are doing >> here is >> already being performed in the Linux SPI framework: at the end of the >> probe >> function, this driver is calling the (legacy) >> devm_spi_register_master(), >> which calls devm_spi_register_controller(). >> >> In drivers/spi/spi.c, function spi_register_controller(), will in >> turn call >> of_register_spi_devices(ctlr) -> of_register_spi_device(ctlr, nc)... >> that >> will end up finally calling function of_spi_parse_dt(ctlr, spi, nc). >> >> The last mentioned function already contains the logic and setup to >> check >> devicetree properties "spi-tx-bus-width" and "spi-rx-bus-width" (and >> some >> others, as well). >> >> This means that spi-mt65xx.c already probed these even before your >> IPM >> implementation, hence ***function of_mtk_spi_parse_dt() is not >> needed***. >> >> Simply drop it and don't check for these properties: that's already >> done. >> >> >> Regards, >> Angelo >> > Hi Angelo, > > Thanks for your advice. > > There are two spi controllor on MT7986. One supports single/dual mode, > the other supports quad mode. Both of them can support spi memory > framework(one's tx/rx bus width is 1/2, the other one's tx/rx bus width > is 1/2/4). > > Can I use of_mtk_spi_parse_dt() to parse the information? What's your > suggestion? > > Thanks! > As I've already said, this does NOT require any devicetree handling in spi-mt65xx.c, as setting the right mode_bits is already handled in drivers/spi/spi.c - please follow the explaination that I have given before to fully understand the situation. Regards, Angelo > >>> + switch (value) { >>> + case 1: >>> + break; >>> + case 2: >>> + master->mode_bits |= SPI_TX_DUAL; >>> + break; >>> + case 4: >>> + master->mode_bits |= SPI_TX_QUAD; >>> + break; >>> + default: >>> + dev_warn(mdata->dev, >>> + "spi-tx-bus-width %d not supported\n", >>> + value); >>> + break; >>> + } >>> + } >>> + >>> + if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) { >>> + switch (value) { >>> + case 1:
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