The AMD Pensando Elba SoC includes a DW apb_ssi v4 controller
with device specific chip-select control. The Elba SoC
provides four chip-selects where the native DW IP supports
two chip-selects. The Elba DW_SPI instance has two native
CS signals that are always overridden.
Signed-off-by: Brad Larson <blarson@amd.com>
---
v10 changes:
- Delete struct dw_spi_elba, use regmap directly in priv
v9 changes:
- Add use of macros GENMASK() and BIT()
- Change ELBA_SPICS_SHIFT() to ELBA_SPICS_OFFSET()
---
drivers/spi/spi-dw-mmio.c | 65 +++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 26c40ea6dd12..2076cb83a11b 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -53,6 +53,20 @@ struct dw_spi_mscc {
void __iomem *spi_mst; /* Not sparx5 */
};
+/*
+ * Elba SoC does not use ssi, pin override is used for cs 0,1 and
+ * gpios for cs 2,3 as defined in the device tree.
+ *
+ * cs: | 1 0
+ * bit: |---3-------2-------1-------0
+ * | cs1 cs1_ovr cs0 cs0_ovr
+ */
+#define ELBA_SPICS_REG 0x2468
+#define ELBA_SPICS_OFFSET(cs) ((cs) << 1)
+#define ELBA_SPICS_MASK(cs) (GENMASK(1, 0) << ELBA_SPICS_OFFSET(cs))
+#define ELBA_SPICS_SET(cs, val) \
+ ((((val) << 1) | BIT(0)) << ELBA_SPICS_OFFSET(cs))
+
/*
* The Designware SPI controller (referred to as master in the documentation)
* automatically deasserts chip select when the tx fifo is empty. The chip
@@ -237,6 +251,56 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
return 0;
}
+static void dw_spi_elba_override_cs(struct regmap *syscon, int cs, int enable)
+{
+ regmap_update_bits(syscon, ELBA_SPICS_REG, ELBA_SPICS_MASK(cs),
+ ELBA_SPICS_SET(cs, enable));
+}
+
+static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
+{
+ struct dw_spi *dws = spi_master_get_devdata(spi->master);
+ struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
+ struct regmap *syscon = dwsmmio->priv;
+ u8 cs;
+
+ cs = spi->chip_select;
+ if (cs < 2)
+ dw_spi_elba_override_cs(syscon, spi->chip_select, enable);
+
+ /*
+ * The DW SPI controller needs a native CS bit selected to start
+ * the serial engine.
+ */
+ spi->chip_select = 0;
+ dw_spi_set_cs(spi, enable);
+ spi->chip_select = cs;
+}
+
+static int dw_spi_elba_init(struct platform_device *pdev,
+ struct dw_spi_mmio *dwsmmio)
+{
+ const char *syscon_name = "amd,pensando-elba-syscon";
+ struct device_node *np = pdev->dev.of_node;
+ struct device_node *node;
+ struct regmap *syscon;
+
+ node = of_parse_phandle(np, syscon_name, 0);
+ if (!node)
+ return dev_err_probe(&pdev->dev, -ENODEV, "failed to find %s\n",
+ syscon_name);
+
+ syscon = syscon_node_to_regmap(node);
+ if (IS_ERR(syscon))
+ return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
+ "syscon regmap lookup failed\n");
+
+ dwsmmio->priv = syscon;
+ 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,
@@ -352,6 +416,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
{ .compatible = "intel,thunderbay-ssi", .data = dw_spi_intel_init},
{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
+ { .compatible = "amd,pensando-elba-spi", .data = dw_spi_elba_init},
{ /* end of table */}
};
MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
--
2.17.1On Sun, Mar 05, 2023 at 08:07:34PM -0800, Brad Larson wrote:
> The AMD Pensando Elba SoC includes a DW apb_ssi v4 controller
> with device specific chip-select control. The Elba SoC
> provides four chip-selects where the native DW IP supports
> two chip-selects. The Elba DW_SPI instance has two native
> CS signals that are always overridden.
>
> Signed-off-by: Brad Larson <blarson@amd.com>
> ---
>
> v10 changes:
> - Delete struct dw_spi_elba, use regmap directly in priv
>
> v9 changes:
> - Add use of macros GENMASK() and BIT()
> - Change ELBA_SPICS_SHIFT() to ELBA_SPICS_OFFSET()
>
> ---
> drivers/spi/spi-dw-mmio.c | 65 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 65 insertions(+)
>
> diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
> index 26c40ea6dd12..2076cb83a11b 100644
> --- a/drivers/spi/spi-dw-mmio.c
> +++ b/drivers/spi/spi-dw-mmio.c
> @@ -53,6 +53,20 @@ struct dw_spi_mscc {
> void __iomem *spi_mst; /* Not sparx5 */
> };
>
> +/*
> + * Elba SoC does not use ssi, pin override is used for cs 0,1 and
> + * gpios for cs 2,3 as defined in the device tree.
> + *
> + * cs: | 1 0
> + * bit: |---3-------2-------1-------0
> + * | cs1 cs1_ovr cs0 cs0_ovr
> + */
> +#define ELBA_SPICS_REG 0x2468
> +#define ELBA_SPICS_OFFSET(cs) ((cs) << 1)
> +#define ELBA_SPICS_MASK(cs) (GENMASK(1, 0) << ELBA_SPICS_OFFSET(cs))
> +#define ELBA_SPICS_SET(cs, val) \
> + ((((val) << 1) | BIT(0)) << ELBA_SPICS_OFFSET(cs))
> +
> /*
> * The Designware SPI controller (referred to as master in the documentation)
> * automatically deasserts chip select when the tx fifo is empty. The chip
> @@ -237,6 +251,56 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
> return 0;
> }
>
> +static void dw_spi_elba_override_cs(struct regmap *syscon, int cs, int enable)
> +{
> + regmap_update_bits(syscon, ELBA_SPICS_REG, ELBA_SPICS_MASK(cs),
> + ELBA_SPICS_SET(cs, enable));
> +}
> +
> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> +{
> + struct dw_spi *dws = spi_master_get_devdata(spi->master);
> + struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
> + struct regmap *syscon = dwsmmio->priv;
> + u8 cs;
> +
> + cs = spi->chip_select;
> + if (cs < 2)
> + dw_spi_elba_override_cs(syscon, spi->chip_select, enable);
> +
> + /*
> + * The DW SPI controller needs a native CS bit selected to start
> + * the serial engine.
> + */
> + spi->chip_select = 0;
> + dw_spi_set_cs(spi, enable);
> + spi->chip_select = cs;
> +}
> +
> +static int dw_spi_elba_init(struct platform_device *pdev,
> + struct dw_spi_mmio *dwsmmio)
> +{
> + const char *syscon_name = "amd,pensando-elba-syscon";
> + struct device_node *np = pdev->dev.of_node;
Drop this since it's used only once below.
> + struct device_node *node;
> + struct regmap *syscon;
> +
> - node = of_parse_phandle(np, syscon_name, 0);
node = of_parse_phandle(dev_of_node(pdev->dev), syscon_name, 0);
> + if (!node)
> + return dev_err_probe(&pdev->dev, -ENODEV, "failed to find %s\n",
> + syscon_name);
Hm, using dev_err_probe() with known error value seems overkill.
> +
> + syscon = syscon_node_to_regmap(node);
> + if (IS_ERR(syscon))
> + return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
> + "syscon regmap lookup failed\n");
of_node_put() is missing in the error and success paths.
-Serge(y)
> +
> + dwsmmio->priv = syscon;
> + 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,
> @@ -352,6 +416,7 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
> { .compatible = "intel,thunderbay-ssi", .data = dw_spi_intel_init},
> { .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
> { .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
> + { .compatible = "amd,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 06, 2023 at 16:00, Serge Semin wrote:
> On Sun, Mar 05, 2023 at 08:07:34PM -0800, Brad Larson wrote:
>> The AMD Pensando Elba SoC includes a DW apb_ssi v4 controller
>> with device specific chip-select control. The Elba SoC
>> provides four chip-selects where the native DW IP supports
>> two chip-selects. The Elba DW_SPI instance has two native
>> CS signals that are always overridden.
>>
>> Signed-off-by: Brad Larson <blarson@amd.com>
>> ---
>>
>> v10 changes:
>> - Delete struct dw_spi_elba, use regmap directly in priv
>>
>> v9 changes:
>> - Add use of macros GENMASK() and BIT()
>> - Change ELBA_SPICS_SHIFT() to ELBA_SPICS_OFFSET()
>>
>> ---
>> drivers/spi/spi-dw-mmio.c | 65 +++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 65 insertions(+)
>>
>> diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
>> index 26c40ea6dd12..2076cb83a11b 100644
>> --- a/drivers/spi/spi-dw-mmio.c
>> +++ b/drivers/spi/spi-dw-mmio.c
>> @@ -53,6 +53,20 @@ struct dw_spi_mscc {
>> void __iomem *spi_mst; /* Not sparx5 */
>> };
>>
>> +/*
>> + * Elba SoC does not use ssi, pin override is used for cs 0,1 and
>> + * gpios for cs 2,3 as defined in the device tree.
>> + *
>> + * cs: | 1 0
>> + * bit: |---3-------2-------1-------0
>> + * | cs1 cs1_ovr cs0 cs0_ovr
>> + */
>> +#define ELBA_SPICS_REG 0x2468
>> +#define ELBA_SPICS_OFFSET(cs) ((cs) << 1)
>> +#define ELBA_SPICS_MASK(cs) (GENMASK(1, 0) << ELBA_SPICS_OFFSET(cs))
>> +#define ELBA_SPICS_SET(cs, val) \
>> + ((((val) << 1) | BIT(0)) << ELBA_SPICS_OFFSET(cs))
>> +
>> /*
>> * The Designware SPI controller (referred to as master in the documentation)
>> * automatically deasserts chip select when the tx fifo is empty. The chip
>> @@ -237,6 +251,56 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
>> return 0;
>> }
>>
>> +static void dw_spi_elba_override_cs(struct regmap *syscon, int cs, int enable)
>> +{
>> + regmap_update_bits(syscon, ELBA_SPICS_REG, ELBA_SPICS_MASK(cs),
>> + ELBA_SPICS_SET(cs, enable));
>> +}
>> +
>> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
>> +{
>> + struct dw_spi *dws = spi_master_get_devdata(spi->master);
>> + struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
>> + struct regmap *syscon = dwsmmio->priv;
>> + u8 cs;
>> +
>> + cs = spi->chip_select;
>> + if (cs < 2)
>> + dw_spi_elba_override_cs(syscon, spi->chip_select, enable);
>> +
>> + /*
>> + * The DW SPI controller needs a native CS bit selected to start
>> + * the serial engine.
>> + */
>> + spi->chip_select = 0;
>> + dw_spi_set_cs(spi, enable);
>> + spi->chip_select = cs;
>> +}
>> +
>> +static int dw_spi_elba_init(struct platform_device *pdev,
>> + struct dw_spi_mmio *dwsmmio)
>> +{
>> + const char *syscon_name = "amd,pensando-elba-syscon";
>
>> + struct device_node *np = pdev->dev.of_node;
>
> Drop this since it's used only once below.
>
Removed
>> + struct device_node *node;
Renamed *node to *np
>> + struct regmap *syscon;
>> +
>> - node = of_parse_phandle(np, syscon_name, 0);
>
> node = of_parse_phandle(dev_of_node(pdev->dev), syscon_name, 0);
>
> + if (!node)
>
>> + return dev_err_probe(&pdev->dev, -ENODEV, "failed to find %s\n",
>> + syscon_name);
>
> Hm, using dev_err_probe() with known error value seems overkill.
Changed to: return -ENODEV
>> +
>
>> + syscon = syscon_node_to_regmap(node);
>> + if (IS_ERR(syscon))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
>> + "syscon regmap lookup failed\n");
>
> of_node_put() is missing in the error and success paths.
Result of the above changes are:
+ const char *syscon_name = "amd,pensando-elba-syscon";
+ struct device_node *np;
+ struct regmap *syscon;
+
+ np = of_parse_phandle(pdev->dev.of_node, syscon_name, 0);
+ if (!np)
+ return -ENODEV;
+
+ syscon = syscon_node_to_regmap(np);
+ of_node_put(np);
+ if (IS_ERR(syscon))
+ return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
+ "syscon regmap lookup failed\n");
Regards,
Brad
On Mon, Mar 06, 2023 at 06:20:02PM -0800, Brad Larson wrote:
> On Mon, Mar 06, 2023 at 16:00, Serge Semin wrote:
> > On Sun, Mar 05, 2023 at 08:07:34PM -0800, Brad Larson wrote:
> >> The AMD Pensando Elba SoC includes a DW apb_ssi v4 controller
> >> with device specific chip-select control. The Elba SoC
> >> provides four chip-selects where the native DW IP supports
> >> two chip-selects. The Elba DW_SPI instance has two native
> >> CS signals that are always overridden.
> >>
> >> Signed-off-by: Brad Larson <blarson@amd.com>
> >> ---
> >>
> >> v10 changes:
> >> - Delete struct dw_spi_elba, use regmap directly in priv
> >>
> >> v9 changes:
> >> - Add use of macros GENMASK() and BIT()
> >> - Change ELBA_SPICS_SHIFT() to ELBA_SPICS_OFFSET()
> >>
> >> ---
> >> drivers/spi/spi-dw-mmio.c | 65 +++++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 65 insertions(+)
> >>
> >> diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
> >> index 26c40ea6dd12..2076cb83a11b 100644
> >> --- a/drivers/spi/spi-dw-mmio.c
> >> +++ b/drivers/spi/spi-dw-mmio.c
> >> @@ -53,6 +53,20 @@ struct dw_spi_mscc {
> >> void __iomem *spi_mst; /* Not sparx5 */
> >> };
> >>
> >> +/*
> >> + * Elba SoC does not use ssi, pin override is used for cs 0,1 and
> >> + * gpios for cs 2,3 as defined in the device tree.
> >> + *
> >> + * cs: | 1 0
> >> + * bit: |---3-------2-------1-------0
> >> + * | cs1 cs1_ovr cs0 cs0_ovr
> >> + */
> >> +#define ELBA_SPICS_REG 0x2468
> >> +#define ELBA_SPICS_OFFSET(cs) ((cs) << 1)
> >> +#define ELBA_SPICS_MASK(cs) (GENMASK(1, 0) << ELBA_SPICS_OFFSET(cs))
> >> +#define ELBA_SPICS_SET(cs, val) \
> >> + ((((val) << 1) | BIT(0)) << ELBA_SPICS_OFFSET(cs))
> >> +
> >> /*
> >> * The Designware SPI controller (referred to as master in the documentation)
> >> * automatically deasserts chip select when the tx fifo is empty. The chip
> >> @@ -237,6 +251,56 @@ static int dw_spi_canaan_k210_init(struct platform_device *pdev,
> >> return 0;
> >> }
> >>
> >> +static void dw_spi_elba_override_cs(struct regmap *syscon, int cs, int enable)
> >> +{
> >> + regmap_update_bits(syscon, ELBA_SPICS_REG, ELBA_SPICS_MASK(cs),
> >> + ELBA_SPICS_SET(cs, enable));
> >> +}
> >> +
> >> +static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
> >> +{
> >> + struct dw_spi *dws = spi_master_get_devdata(spi->master);
> >> + struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
> >> + struct regmap *syscon = dwsmmio->priv;
> >> + u8 cs;
> >> +
> >> + cs = spi->chip_select;
> >> + if (cs < 2)
> >> + dw_spi_elba_override_cs(syscon, spi->chip_select, enable);
> >> +
> >> + /*
> >> + * The DW SPI controller needs a native CS bit selected to start
> >> + * the serial engine.
> >> + */
> >> + spi->chip_select = 0;
> >> + dw_spi_set_cs(spi, enable);
> >> + spi->chip_select = cs;
> >> +}
> >> +
> >> +static int dw_spi_elba_init(struct platform_device *pdev,
> >> + struct dw_spi_mmio *dwsmmio)
> >> +{
> >> + const char *syscon_name = "amd,pensando-elba-syscon";
> >
> >> + struct device_node *np = pdev->dev.of_node;
> >
> > Drop this since it's used only once below.
> >
>
> Removed
>
> >> + struct device_node *node;
>
> Renamed *node to *np
>
> >> + struct regmap *syscon;
> >> +
> >> - node = of_parse_phandle(np, syscon_name, 0);
> >
> > node = of_parse_phandle(dev_of_node(pdev->dev), syscon_name, 0);
> >
> > + if (!node)
> >
> >> + return dev_err_probe(&pdev->dev, -ENODEV, "failed to find %s\n",
> >> + syscon_name);
> >
> > Hm, using dev_err_probe() with known error value seems overkill.
>
> Changed to: return -ENODEV
>
> >> +
> >
> >> + syscon = syscon_node_to_regmap(node);
> >> + if (IS_ERR(syscon))
> >> + return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
> >> + "syscon regmap lookup failed\n");
> >
> > of_node_put() is missing in the error and success paths.
>
> Result of the above changes are:
>
> + const char *syscon_name = "amd,pensando-elba-syscon";
> + struct device_node *np;
> + struct regmap *syscon;
> +
> + np = of_parse_phandle(pdev->dev.of_node, syscon_name, 0);
> + if (!np)
> + return -ENODEV;
> +
> + syscon = syscon_node_to_regmap(np);
> + of_node_put(np);
> + if (IS_ERR(syscon))
> + return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
> + "syscon regmap lookup failed\n");
As Andy correctly noted this can be fully converted to just a single call:
syscon_regmap_lookup_by_phandle().
and replace pdev->dev.of_node with dev_of_node(pdev->dev).
-Serge(y)
>
> Regards,
> Brad
On Mon, Mar 6, 2023 at 6:00 PM Serge Semin <fancer.lancer@gmail.com> wrote: > On Sun, Mar 05, 2023 at 08:07:34PM -0800, Brad Larson wrote: ... > > - node = of_parse_phandle(np, syscon_name, 0); > > node = of_parse_phandle(dev_of_node(pdev->dev), syscon_name, 0); Side note: I would rather see syscon_fwnode_to_regmap() instead of this. And IIRC syscon already has an API to find by name. > > + if (!node) > > > + return dev_err_probe(&pdev->dev, -ENODEV, "failed to find %s\n", > > + syscon_name); > > Hm, using dev_err_probe() with known error value seems overkill. It's allowed use and it helps to drop a few unnecessary lines of code. > > + syscon = syscon_node_to_regmap(node); > > + if (IS_ERR(syscon)) > > + return dev_err_probe(&pdev->dev, PTR_ERR(syscon), > > + "syscon regmap lookup failed\n"); -- With Best Regards, Andy Shevchenko
On Mon, Mar 06, 2023 at 09:59:29PM +0200, Andy Shevchenko wrote: > On Mon, Mar 6, 2023 at 6:00 PM Serge Semin <fancer.lancer@gmail.com> wrote: > > On Sun, Mar 05, 2023 at 08:07:34PM -0800, Brad Larson wrote: > > ... > > > > - node = of_parse_phandle(np, syscon_name, 0); > > > > node = of_parse_phandle(dev_of_node(pdev->dev), syscon_name, 0); > > Side note: I would rather see syscon_fwnode_to_regmap() instead of > this. And IIRC syscon already has an API to find by name. Ah, right. Though it's called syscon_regmap_lookup_by_phandle() and it can be used to replace the entire pattern: "Parse property; Find node by phandle; Get regmap by node". Basically the of_parse_phandle() and syscon_node_to_regmap() methods invocation can be replaced with just a single function call. Thus there won't be need to worry about decrementing the found DT-node ref-counter. > > > > + if (!node) > > > > > + return dev_err_probe(&pdev->dev, -ENODEV, "failed to find %s\n", > > > + syscon_name); > > > > Hm, using dev_err_probe() with known error value seems overkill. > > It's allowed use and it helps to drop a few unnecessary lines of code. Ok, seeing there is no alternative to that method which would return the passed error but wouldn't have a name implying the silent deferred-probe error semantics. -Serge(y) > > > > + syscon = syscon_node_to_regmap(node); > > > + if (IS_ERR(syscon)) > > > + return dev_err_probe(&pdev->dev, PTR_ERR(syscon), > > > + "syscon regmap lookup failed\n"); > > -- > With Best Regards, > Andy Shevchenko
© 2016 - 2026 Red Hat, Inc.