From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pratyush Yadav Subject: Re: [PATCH v2 02/11] spi: set mode bits for "spi-rx-dtr" and "spi-tx-dtr" Date: Mon, 2 Mar 2020 15:18:31 +0530 Message-ID: <20200302094829.opazalwldrdn4s7y@ti.com> References: <20200226093703.19765-1-p.yadav@ti.com> <20200226093703.19765-3-p.yadav@ti.com> <20200227172247.0e8ec459@collabora.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Mark Rutland , devicetree@vger.kernel.org, Vignesh Raghavendra , Tudor Ambarus , Richard Weinberger , Sekhar Nori , linux-kernel@vger.kernel.org, Rob Herring , linux-spi@vger.kernel.org, Mark Brown , linux-mtd@lists.infradead.org, Miquel Raynal To: Boris Brezillon Return-path: Content-Disposition: inline In-Reply-To: <20200227172247.0e8ec459@collabora.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+gldm-linux-mtd-36=m.gmane-mx.org@lists.infradead.org List-Id: linux-spi.vger.kernel.org Hi Boris, On 27/02/20 05:23PM, Boris Brezillon wrote: > On Wed, 26 Feb 2020 15:06:54 +0530 > Pratyush Yadav wrote: > > > These two DT properties express DTR receive and transmit capabilities of > > a SPI flash and controller. Introduce two new mode bits: SPI_RX_DTR and > > SPI_TX_DTR which correspond to the new DT properties. Set these bits > > when the two corresponding properties are present in the device tree. > > Also update the detection of unsupported mode bits to include the new > > bits. > > > > Signed-off-by: Pratyush Yadav > > --- > > drivers/spi/spi.c | 10 +++++++++- > > include/linux/spi/spi.h | 2 ++ > > 2 files changed, 11 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > > index 38b4c78df506..25c8ed9343f9 100644 > > --- a/drivers/spi/spi.c > > +++ b/drivers/spi/spi.c > > @@ -1927,6 +1927,13 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, > > } > > } > > > > + /* Device DTR mode. */ > > + if (of_property_read_bool(nc, "spi-tx-dtr")) > > + spi->mode |= SPI_TX_DTR; > > + > > + if (of_property_read_bool(nc, "spi-rx-dtr")) > > + spi->mode |= SPI_RX_DTR; > > + > > If this DTR mode is only used in spi-mem, maybe we shouldn't add those > flags. SPI mem devices are usually smart enough to advertise what they > support, and the subsystem in charge of those devices (in this specific > case, spi-nor) will check what the controller supports > using spi_mem_supports_op(). The only case we might have to deal with > at some point is board level limitations (disabling DTR because the > routing prevents using this mode). Yes, being able to handle board-level limitations is the main reason behind this change. There should be a way to over-ride the use of DTR for a given board. And IIUC, SPI allows doing the same for Rx and Tx buswidth. So I don't see why we should deviate from that model. > > if (spi_controller_is_slave(ctlr)) { > > if (!of_node_name_eq(nc, "slave")) { > > dev_err(&ctlr->dev, "%pOF is not called 'slave'\n", > > @@ -3252,7 +3259,8 @@ int spi_setup(struct spi_device *spi) > > bad_bits &= ~SPI_CS_HIGH; > > ugly_bits = bad_bits & > > (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL | > > - SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL); > > + SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL | > > + SPI_TX_DTR | SPI_RX_DTR); > > if (ugly_bits) { > > dev_warn(&spi->dev, > > "setup: ignoring unsupported mode bits %x\n", > > diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h > > index 6d16ba01ff5a..bf1108318389 100644 > > --- a/include/linux/spi/spi.h > > +++ b/include/linux/spi/spi.h > > @@ -183,6 +183,8 @@ struct spi_device { > > #define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */ > > #define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */ > > #define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */ > > +#define SPI_RX_DTR 0x10000 /* receive in DTR mode */ > > +#define SPI_TX_DTR 0x20000 /* transmit in DTR mode */ > > int irq; > > void *controller_state; > > void *controller_data; > -- Regards, Pratyush Yadav Texas Instruments India ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/