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Date:   Mon, 2 Jul 2018 17:12:58 +0100
From:   Mark Brown <broonie@kernel.org>
To:     Andreas =?iso-8859-1?Q?F=E4rber?= <afaerber@suse.de>
Cc:     netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Jian-Hong Pan <starnight@g.ncu.edu.tw>,
        Jiri Pirko <jiri@resnulli.us>,
        Marcel Holtmann <marcel@holtmann.org>,
        "David S . Miller" <davem@davemloft.net>,
        Matthias Brugger <mbrugger@suse.com>,
        Janus Piwek <jpiwek@arroweurope.com>,
        Michael =?iso-8859-1?Q?R=F6der?= <michael.roeder@avnet.eu>,
        Dollar Chen <dollar.chen@wtmec.com>,
        Ken Yu <ken.yu@rakwireless.com>,
        Ben Whitten <ben.whitten@lairdtech.com>,
        Steve deRosier <derosier@gmail.com>, linux-spi@vger.kernel.org
Subject: Re: [RFC net-next 15/15] net: lora: Add Semtech SX1301
Message-ID: <20180702161258.GA18744@sirena.org.uk>
References: <20180701110804.32415-1-afaerber@suse.de>
 <20180701110804.32415-16-afaerber@suse.de>
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On Sun, Jul 01, 2018 at 01:08:04PM +0200, Andreas F=E4rber wrote:

> +static void sx1301_radio_spi_set_cs(struct spi_device *spi, bool enable)
> +{
> +	int ret;
> +
> +	dev_dbg(&spi->dev, "setting SPI CS to %s\n", enable ? "1" : "0");
> +
> +	if (enable)
> +		return;
> +
> +	ret =3D sx1301_radio_set_cs(spi->controller, enable);
> +	if (ret)
> +		dev_warn(&spi->dev, "failed to write CS (%d)\n", ret);
> +}

So we never disable chip select?

> +	if (tx_buf) {
> +		ret =3D sx1301_write(ssx->parent, ssx->regs + REG_RADIO_X_ADDR, tx_buf=
 ? tx_buf[0] : 0);

This looks confused.  We're in an if (tx_buf) block but there's a use of
the ternery operator that appears to be checking if we have a tx_buf?

> +		if (ret) {
> +			dev_err(&spi->dev, "SPI radio address write failed\n");
> +			return ret;
> +		}
> +
> +		ret =3D sx1301_write(ssx->parent, ssx->regs + REG_RADIO_X_DATA, (tx_bu=
f && xfr->len >=3D 2) ? tx_buf[1] : 0);
> +		if (ret) {
> +			dev_err(&spi->dev, "SPI radio data write failed\n");
> +			return ret;
> +		}

This looks awfully like you're coming in at the wrong abstraction layer
and the hardware actually implements a register abstraction rather than
a SPI one so you should be using regmap as the abstraction.

> +	if (rx_buf) {
> +		ret =3D sx1301_read(ssx->parent, ssx->regs + REG_RADIO_X_DATA_READBACK=
, &rx_buf[xfr->len - 1]);
> +		if (ret) {
> +			dev_err(&spi->dev, "SPI radio data read failed\n");
> +			return ret;
> +		}
> +	}

For a read we never set an address?

> +static void sx1301_radio_setup(struct spi_controller *ctrl)
> +{
> +	ctrl->mode_bits =3D SPI_CS_HIGH | SPI_NO_CS;

This controller has no chip select but we provided a set_cs operation?

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