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Message-ID: <20230307022002.28874-1-blarson@amd.com>
Date: Mon, 6 Mar 2023 18:20:02 -0800
From: Brad Larson <blarson@....com>
To: <fancer.lancer@...il.com>
CC: <adrian.hunter@...el.com>, <alcooperx@...il.com>,
<andy.shevchenko@...il.com>, <arnd@...db.de>, <blarson@....com>,
<brendan.higgins@...ux.dev>, <briannorris@...omium.org>,
<brijeshkumar.singh@....com>, <broonie@...nel.org>,
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<devicetree@...r.kernel.org>, <gerg@...ux-m68k.org>,
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<krzysztof.kozlowski+dt@...aro.org>, <lee.jones@...aro.org>,
<lee@...nel.org>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-mmc@...r.kernel.org>,
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<samuel@...lland.org>, <skhan@...uxfoundation.org>,
<suravee.suthikulpanit@....com>, <thomas.lendacky@....com>,
<tonyhuang.sunplus@...il.com>, <ulf.hansson@...aro.org>,
<vaishnav.a@...com>, <will@...nel.org>,
<yamada.masahiro@...ionext.com>
Subject: Re: [PATCH v10 10/15] spi: dw: Add support for AMD Pensando Elba SoC
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@....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
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