linux-kernel - RE: [PATCH 2/3] spi: tegra210-quad: Add wait polling support

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Date:   Thu, 17 Mar 2022 09:02:36 +0000
From:   Krishna Yarlagadda <kyarlagadda@...dia.com>
To:     Jonathan Hunter <jonathanh@...dia.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "thierry.reding@...il.com" <thierry.reding@...il.com>,
        "linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>,
        "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
        Ashish Singhal <ashishsingha@...dia.com>
CC:     Sowjanya Komatineni <skomatineni@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 2/3] spi: tegra210-quad: Add wait polling support

> -----Original Message-----
> From: Jonathan Hunter <jonathanh@...dia.com>
> Sent: 17 March 2022 14:25
> To: Krishna Yarlagadda <kyarlagadda@...dia.com>; broonie@...nel.org; thierry.reding@...il.com; linux-spi@...r.kernel.org; linux-
> tegra@...r.kernel.org; Ashish Singhal <ashishsingha@...dia.com>
> Cc: Sowjanya Komatineni <skomatineni@...dia.com>; Laxman Dewangan <ldewangan@...dia.com>; robh+dt@...nel.org;
> devicetree@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 2/3] spi: tegra210-quad: Add wait polling support
> 
> 
> On 17/03/2022 01:20, Krishna Yarlagadda wrote:
> > Controller can poll for wait state inserted by TPM device and
> > handle it.
> >
> > Signed-off-by: Krishna Yarlagadda <kyarlagadda@...dia.com>
> > ---
> >   drivers/spi/spi-tegra210-quad.c | 31 +++++++++++++++++++++++++++++++
> >   1 file changed, 31 insertions(+)
> >
> > diff --git a/drivers/spi/spi-tegra210-quad.c b/drivers/spi/spi-tegra210-quad.c
> > index a2e225e8f7f0..ecf171bfcdce 100644
> > --- a/drivers/spi/spi-tegra210-quad.c
> > +++ b/drivers/spi/spi-tegra210-quad.c
> > @@ -142,6 +142,7 @@
> >
> >   #define QSPI_GLOBAL_CONFIG			0X1a4
> >   #define QSPI_CMB_SEQ_EN				BIT(0)
> > +#define QSPI_TPM_WAIT_POLL_EN			BIT(1)
> >
> >   #define QSPI_CMB_SEQ_ADDR			0x1a8
> >   #define QSPI_ADDRESS_VALUE_SET(X)		(((x) & 0xFFFF) << 0)
> > @@ -165,11 +166,13 @@ struct tegra_qspi_soc_data {
> >   	bool has_dma;
> >   	bool cmb_xfer_capable;
> >   	bool cs_count;
> > +	bool has_wait_polling;
> >   };
> >
> >   struct tegra_qspi_client_data {
> >   	int tx_clk_tap_delay;
> >   	int rx_clk_tap_delay;
> > +	bool wait_polling;
> >   };
> >
> >   struct tegra_qspi {
> > @@ -833,6 +836,11 @@ static u32 tegra_qspi_setup_transfer_one(struct spi_device *spi, struct spi_tran
> >   		else
> >   			command1 |= QSPI_CONTROL_MODE_0;
> >
> > +		if (tqspi->soc_data->cmb_xfer_capable)
> > +			command1 &= ~QSPI_CS_SW_HW;
> > +		else
> > +			command1 |= QSPI_CS_SW_HW;
> > +
> >   		if (spi->mode & SPI_CS_HIGH)
> >   			command1 |= QSPI_CS_SW_VAL;
> >   		else
> > @@ -917,6 +925,7 @@ static int tegra_qspi_start_transfer_one(struct spi_device *spi,
> >
> >   static struct tegra_qspi_client_data *tegra_qspi_parse_cdata_dt(struct spi_device *spi)
> >   {
> > +	struct tegra_qspi *tqspi = spi_master_get_devdata(spi->master);
> >   	struct tegra_qspi_client_data *cdata;
> >
> >   	cdata = devm_kzalloc(&spi->dev, sizeof(*cdata), GFP_KERNEL);
> > @@ -927,6 +936,11 @@ static struct tegra_qspi_client_data *tegra_qspi_parse_cdata_dt(struct spi_devic
> >   				 &cdata->tx_clk_tap_delay);
> >   	device_property_read_u32(&spi->dev, "nvidia,rx-clk-tap-delay",
> >   				 &cdata->rx_clk_tap_delay);
> > +	if (tqspi->soc_data->has_wait_polling)
> > +		cdata->wait_polling = device_property_read_bool
> > +					(&spi->dev,
> > +					 "nvidia,wait-polling");
> > +
> 
> 
> This looks odd. Why do we need this device-tree property if it is
> already specified in the SoC data?
Soc data specifies chip is capable of wait-polling.
Wait polling still has to be selected on slave devices that can support it.
I will add one line description for the properties in next version.
> 
> Jon
> 
> --
> nvpublic