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From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH v5 12/14] net: dsa: add KSZ9477 switch SPI driver
Date: Sat, 30 Jul 2022 13:27:29 +0200	[thread overview]
Message-ID: <20220730112729.GA4662@pengutronix.de> (raw)
In-Reply-To: <7f14c5f2-ec1e-8d76-6aa2-a2a1c4313be5@pengutronix.de>

Hello Ahmad,

On Sat, Jul 30, 2022 at 11:10:34AM +0200, Ahmad Fatoum wrote:
> Hello Oleksij,
> 
> On 13.04.22 10:22, Oleksij Rempel wrote:
> > +static int microchip_switch_probe(struct device_d *dev)
> > +{
> > +	struct ksz_switch *priv;
> > +	int ret = 0, gpio;
> > +	struct dsa_switch *ds;
> > +
> > +	priv = xzalloc(sizeof(*priv));
> > +
> > +	dev->priv = priv;
> > +	priv->dev = dev;
> > +
> > +	priv->spi = (struct spi_device *)dev->type_data;
> > +	priv->spi->mode = SPI_MODE_0;
> 
> The kernel DSA driver configures SPI_MODE_3.
> Is it intended that you configure the barebox driver differently?

Yes. I wonted to investigate it deeper but didn't found time.
According to the KSZ9477S data sheet, SPI TIMING diagram:
we have following pictures:

FIGURE 6-9: SPI DATA INPUT TIMING

CLK ____/---\__/---\__/---\__/---\__/---\__
SDI   {-----}{-----}{-----}{-----}{-----}

This is CPOL=0 and CPHA=0 == SPI_MODE_0

And FIGURE 6-10: SPI DATA OUTPUT TIMING
CLK ____/---\__/---\__/---\__/---\__/---\__
SDO   {-----}{-----}{-----}{-----}{-----}
(LOW-SPEED MODE) This is CPOL=0 and CPHA=0 == SPI_MODE_0
SDO      {-----}{-----}{-----}{-----}{-----}
(HIGH-SPEED MODE) This is CPOL=0 and CPHA=1 == SPI_MODE_1

If I see it correctly SPI_MODE_3 is not documented at all. And
SPI_MODE_3 didn't worked for me, this is why I started investigating it
:)

Regards,
Oleksij
-- 
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  reply	other threads:[~2022-07-30 11:29 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-13  8:21 [PATCH v5 00/14] provide DSA support Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 01/14] net: add RX preprocessor support Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 02/14] net: add of_find_eth_device_by_node() function Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 03/14] net: phy: export of_phy_register_fixed_link() function Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 04/14] net: add DSA framework to support basic switch functionality Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 05/14] driver: add dev_get_priv() helper Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 06/14] net: port part of if_vlan header from kernel v5.17 Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 07/14] spi: port spi_sync_transfer() function " Oleksij Rempel
2022-04-13  8:21 ` [PATCH v5 08/14] net: mdio: add MDIO_DEVAD_NONE define Oleksij Rempel
2022-04-13  8:22 ` [PATCH v5 09/14] net: phy: make sure MDIO bus is probed if we search for the PHY Oleksij Rempel
2022-04-13  8:22 ` [PATCH v5 10/14] of_net: add rev-rmii support Oleksij Rempel
2022-04-13  8:22 ` [PATCH v5 11/14] net: dsa: add support for SJA11xx switches Oleksij Rempel
2022-04-13  8:22 ` [PATCH v5 12/14] net: dsa: add KSZ9477 switch SPI driver Oleksij Rempel
2022-07-30  9:10   ` Ahmad Fatoum
2022-07-30 11:27     ` Oleksij Rempel [this message]
2022-04-13  8:22 ` [PATCH v5 13/14] hexdump: provide support for dev_print_hex_dump() Oleksij Rempel
2022-04-13  8:22 ` [PATCH v5 14/14] add ethlog command Oleksij Rempel
2022-04-14  7:42 ` [PATCH v5 00/14] provide DSA support Sascha Hauer

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