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 <[email protected]>
---
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) {
+ /*
+ * 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
On Mon, Mar 29, 2021 at 5:01 AM Brad Larson <[email protected]> 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);
> + }
> +}
--
With Best Regards,
Andy Shevchenko
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?
On Mon, Mar 29, 2021 at 8:58 AM Mark Brown <[email protected]> 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.
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 <[email protected]>
> ---
> 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
>
Hi Sergey,
On Wed, Mar 31, 2021 at 11:00 AM Serge Semin <[email protected]> wrote:
>
> 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.
(...)
> > +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.
Thanks for your patience. It took me a while to understand what you
were asking about regarding dw_spi_set_cs() due to the unnecessarily
complicated function that was being used. The current implementation
I propose for v3 patchset is this which as you identified handles cs
active high/low properly.
static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
{
spi->chip_select = 0;
dw_spi_set_cs(spi, enable);
}
Regards,
Brad
Hi Andy,
On Mon, Mar 29, 2021 at 3:43 AM Andy Shevchenko
<[email protected]> wrote:
>
> On Mon, Mar 29, 2021 at 5:01 AM Brad Larson <[email protected]> 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?
This function has been re-written to use the existing dw_spi_set_cs().
This is what I currently plan for the v3 patchset.
static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
{
spi->chip_select = 0;
dw_spi_set_cs(spi, enable);
}
Regards,
Brad