diff mbox series

[v2,03/13] spi: dw: Add support for Pensando Elba SoC SPI

Message ID 20210329015938.20316-4-brad@pensando.io (mailing list archive)
State New
Headers show
Series Support Pensando Elba SoC | expand

Commit Message

Brad Larson March 29, 2021, 1:59 a.m. UTC
The Pensando Elba SoC uses a GPIO based chip select
for two DW SPI busses with each bus having two
chip selects.

Signed-off-by: Brad Larson <brad@pensando.io>
---
 drivers/spi/spi-dw-mmio.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

Comments

Andy Shevchenko March 29, 2021, 10:43 a.m. UTC | #1
On Mon, Mar 29, 2021 at 5:01 AM Brad Larson <brad@pensando.io> wrote:
>
> The Pensando Elba SoC uses a GPIO based chip select
> for two DW SPI busses with each bus having two
> chip selects.

...

> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> +{
> +       struct dw_spi *dws = spi_master_get_devdata(spi->master);
> +
> +       if (!enable) {

Can you use positive conditional?

> +               /*
> +                * Using a GPIO-based chip-select, the DW SPI
> +                * controller still needs its own CS bit selected
> +                * to start the serial engine.  On Elba the specific
> +                * CS doesn't matter to start the serial engine,
> +                * so using CS0.
> +                */
> +               dw_writel(dws, DW_SPI_SER, BIT(0));
> +       } else {
> +               dw_writel(dws, DW_SPI_SER, 0);
> +       }
> +}
Mark Brown March 29, 2021, 3:58 p.m. UTC | #2
On Sun, Mar 28, 2021 at 06:59:28PM -0700, Brad Larson wrote:

> @@ -56,7 +56,7 @@ struct dw_spi_mscc {
>  /*
>   * The Designware SPI controller (referred to as master in the documentation)
>   * automatically deasserts chip select when the tx fifo is empty. The chip
> - * selects then needs to be either driven as GPIOs or, for the first 4 using the
> + * selects then needs to be either driven as GPIOs or, for the first 4 using
>   * the SPI boot controller registers. the final chip select is an OR gate
>   * between the Designware SPI controller and the SPI boot controller.
>   */

This is an unrelated fix, please send as a separate patch as covered in
submitting-patches.rst.

> @@ -237,6 +237,31 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> +{
> +	struct dw_spi *dws = spi_master_get_devdata(spi->master);
> +
> +	if (!enable) {
> +		/*
> +		 * Using a GPIO-based chip-select, the DW SPI
> +		 * controller still needs its own CS bit selected
> +		 * to start the serial engine.  On Elba the specific
> +		 * CS doesn't matter to start the serial engine,
> +		 * so using CS0.
> +		 */

Why does this comment only apply to one branch of the conditional?
Brad Larson March 30, 2021, 2:28 a.m. UTC | #3
On Mon, Mar 29, 2021 at 8:58 AM Mark Brown <broonie@kernel.org> wrote:
>
> On Sun, Mar 28, 2021 at 06:59:28PM -0700, Brad Larson wrote:
>
> > @@ -56,7 +56,7 @@ struct dw_spi_mscc {
> >  /*
> >   * The Designware SPI controller (referred to as master in the documentation)
> >   * automatically deasserts chip select when the tx fifo is empty. The chip
> > - * selects then needs to be either driven as GPIOs or, for the first 4 using the
> > + * selects then needs to be either driven as GPIOs or, for the first 4 using
> >   * the SPI boot controller registers. the final chip select is an OR gate
> >   * between the Designware SPI controller and the SPI boot controller.
> >   */
>
> This is an unrelated fix, please send as a separate patch as covered in
> submitting-patches.rst.

I'll remove this.  Belongs in a trivial patch set.

> > @@ -237,6 +237,31 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
> >       return 0;
> >  }
> >
> > +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> > +{
> > +     struct dw_spi *dws = spi_master_get_devdata(spi->master);
> > +
> > +     if (!enable) {
> > +             /*
> > +              * Using a GPIO-based chip-select, the DW SPI
> > +              * controller still needs its own CS bit selected
> > +              * to start the serial engine.  On Elba the specific
> > +              * CS doesn't matter to start the serial engine,
> > +              * so using CS0.
> > +              */
>
> Why does this comment only apply to one branch of the conditional?

It doesn't, I'll move it outside the conditional.
Serge Semin March 31, 2021, 6 p.m. UTC | #4
On Sun, Mar 28, 2021 at 06:59:28PM -0700, Brad Larson wrote:
> The Pensando Elba SoC uses a GPIO based chip select
> for two DW SPI busses with each bus having two
> chip selects.
> 
> Signed-off-by: Brad Larson <brad@pensando.io>
> ---
>  drivers/spi/spi-dw-mmio.c | 28 +++++++++++++++++++++++++++-
>  1 file changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
> index 17c06039a74d..c323a5ceecb8 100644
> --- a/drivers/spi/spi-dw-mmio.c
> +++ b/drivers/spi/spi-dw-mmio.c
> @@ -56,7 +56,7 @@ struct dw_spi_mscc {
>  /*
>   * The Designware SPI controller (referred to as master in the documentation)
>   * automatically deasserts chip select when the tx fifo is empty. The chip
> - * selects then needs to be either driven as GPIOs or, for the first 4 using the
> + * selects then needs to be either driven as GPIOs or, for the first 4 using
>   * the SPI boot controller registers. the final chip select is an OR gate
>   * between the Designware SPI controller and the SPI boot controller.
>   */
> @@ -237,6 +237,31 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> +{
> +	struct dw_spi *dws = spi_master_get_devdata(spi->master);
> +

> +	if (!enable) {

Please, be more attentive to the review-comments given to you before
resending a new patchset. One more time. This version of set_cs won't
work for Active-high CS. Each SPI controller working with GPIO-based
chip-select is marked as supporting that feature. So your DW
SPI controller won't be able to work correctly with SPI-devices
activated by active-high chip-select signal. Note default
dw_spi_set_cs() callback supports that.

-Sergey

> +		/*
> +		 * Using a GPIO-based chip-select, the DW SPI
> +		 * controller still needs its own CS bit selected
> +		 * to start the serial engine.  On Elba the specific
> +		 * CS doesn't matter to start the serial engine,
> +		 * so using CS0.
> +		 */
> +		dw_writel(dws, DW_SPI_SER, BIT(0));
> +	} else {
> +		dw_writel(dws, DW_SPI_SER, 0);
> +	}
> +}
> +
> +static int dw_spi_elba_init(struct platform_device *pdev,
> +			    struct dw_spi_mmio *dwsmmio)
> +{
> +	dwsmmio->dws.set_cs = dw_spi_elba_set_cs;
> +	return 0;
> +}
> +
>  static int dw_spi_mmio_probe(struct platform_device *pdev)
>  {
>  	int (*init_func)(struct platform_device *pdev,
> @@ -351,6 +376,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
>  	{ .compatible = "intel,keembay-ssi", .data = dw_spi_keembay_init},
>  	{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
>  	{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
> +	{ .compatible = "pensando,elba-spi", .data = dw_spi_elba_init},
>  	{ /* end of table */}
>  };
>  MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
> -- 
> 2.17.1
>
diff mbox series

Patch

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 17c06039a74d..c323a5ceecb8 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -56,7 +56,7 @@  struct dw_spi_mscc {
 /*
  * The Designware SPI controller (referred to as master in the documentation)
  * automatically deasserts chip select when the tx fifo is empty. The chip
- * selects then needs to be either driven as GPIOs or, for the first 4 using the
+ * selects then needs to be either driven as GPIOs or, for the first 4 using
  * the SPI boot controller registers. the final chip select is an OR gate
  * between the Designware SPI controller and the SPI boot controller.
  */
@@ -237,6 +237,31 @@  static int dw_spi_canaan_k210_init(struct platform_device *pdev,
 	return 0;
 }
 
+static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
+{
+	struct dw_spi *dws = spi_master_get_devdata(spi->master);
+
+	if (!enable) {
+		/*
+		 * Using a GPIO-based chip-select, the DW SPI
+		 * controller still needs its own CS bit selected
+		 * to start the serial engine.  On Elba the specific
+		 * CS doesn't matter to start the serial engine,
+		 * so using CS0.
+		 */
+		dw_writel(dws, DW_SPI_SER, BIT(0));
+	} else {
+		dw_writel(dws, DW_SPI_SER, 0);
+	}
+}
+
+static int dw_spi_elba_init(struct platform_device *pdev,
+			    struct dw_spi_mmio *dwsmmio)
+{
+	dwsmmio->dws.set_cs = dw_spi_elba_set_cs;
+	return 0;
+}
+
 static int dw_spi_mmio_probe(struct platform_device *pdev)
 {
 	int (*init_func)(struct platform_device *pdev,
@@ -351,6 +376,7 @@  static const struct of_device_id dw_spi_mmio_of_match[] = {
 	{ .compatible = "intel,keembay-ssi", .data = dw_spi_keembay_init},
 	{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
 	{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
+	{ .compatible = "pensando,elba-spi", .data = dw_spi_elba_init},
 	{ /* end of table */}
 };
 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);