Re: [PATCH V4 4/6] spi: mediatek: add spi memory support for ipm design

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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@xxxxxxxxxxxx>
---
   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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