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Message-ID: <b10252e3-41bf-4d5c-bbd1-0af4c723884f@opensource.cirrus.com>
Date: Tue, 21 Nov 2023 13:58:07 +0000
From: Stefan Binding <sbinding@...nsource.cirrus.com>
To: "Mahapatra, Amit Kumar" <amit.kumar-mahapatra@....com>,
"broonie@...nel.org" <broonie@...nel.org>,
"tudor.ambarus@...aro.org" <tudor.ambarus@...aro.org>,
"pratyush@...nel.org" <pratyush@...nel.org>,
"miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
"richard@....at" <richard@....at>,
"vigneshr@...com" <vigneshr@...com>
CC: "linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"michael@...le.cc" <michael@...le.cc>,
"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
"nicolas.ferre@...rochip.com" <nicolas.ferre@...rochip.com>,
"alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>,
"claudiu.beznea@...on.dev" <claudiu.beznea@...on.dev>,
"Simek, Michal" <michal.simek@....com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"git (AMD-Xilinx)" <git@....com>,
"amitrkcian2002@...il.com" <amitrkcian2002@...il.com>,
"patches@...nsource.cirrus.com" <patches@...nsource.cirrus.com>
Subject: Re: [PATCH v10 1/8] spi: Add multi-cs memories support in SPI core
On 21/11/2023 07:39, Mahapatra, Amit Kumar wrote:
> Hello Stefan,
>
>> -----Original Message-----
>> From: Stefan Binding <sbinding@...nsource.cirrus.com>
>> Sent: Monday, November 20, 2023 8:00 PM
>> To: Mahapatra, Amit Kumar <amit.kumar-mahapatra@....com>;
>> broonie@...nel.org; tudor.ambarus@...aro.org; pratyush@...nel.org;
>> miquel.raynal@...tlin.com; richard@....at; vigneshr@...com
>> Cc: linux-spi@...r.kernel.org; linux-kernel@...r.kernel.org;
>> michael@...le.cc; linux-mtd@...ts.infradead.org;
>> nicolas.ferre@...rochip.com; alexandre.belloni@...tlin.com;
>> claudiu.beznea@...on.dev; Simek, Michal <michal.simek@....com>; linux-
>> arm-kernel@...ts.infradead.org; git (AMD-Xilinx) <git@....com>;
>> amitrkcian2002@...il.com; patches@...nsource.cirrus.com
>> Subject: Re: [PATCH v10 1/8] spi: Add multi-cs memories support in SPI core
>>
>>
>> On 18/11/2023 13:54, Amit Kumar Mahapatra wrote:
>>> AMD-Xilinx GQSPI controller has two advanced mode that allows the
>>> controller to consider two flashes as one single device.
>>>
>>> One of these two mode is the parallel mode in which each byte of data
>>> is stored in both devices, the even bits in the lower flash & the odd
>>> bits in the upper flash. The byte split is automatically handled by
>>> the QSPI controller.
>>>
>>> The other mode is the stacked mode in which both the flashes share the
>>> same SPI bus but each of the device contain half of the data. In this
>>> mode, the controller does not follow CS requests but instead
>>> internally wires the two CS levels with the value of the most significant
>> address bit.
>>> For supporting both these modes SPI core need to be updated for
>>> providing multiple CS for a single SPI device.
>>>
>>> For adding multi CS support the SPI device need to be aware of all the
>>> CS values. So, the "chip_select" member in the spi_device structure is
>>> now an array that holds all the CS values.
>>>
>>> spi_device structure now has a "cs_index_mask" member. This acts as an
>>> index to the chip_select array. If nth bit of spi->cs_index_mask is
>>> set then the driver would assert spi->chip_select[n].
>>>
>>> In parallel mode all the chip selects are asserted/de-asserted
>>> simultaneously and each byte of data is stored in both devices, the
>>> even bits in one, the odd bits in the other. The split is
>>> automatically handled by the GQSPI controller. The GQSPI controller
>>> supports a maximum of two flashes connected in parallel mode. A
>>> SPI_CONTROLLER_MULTI_CS flag bit is added in the spi controller flags,
>>> through ctlr->flags the spi core will make sure that the controller is
>>> capable of handling multiple chip selects at once.
>>>
>>> For supporting multiple CS via GPIO the cs_gpiod member of the
>>> spi_device structure is now an array that holds the gpio descriptor
>>> for each chipselect.
>>>
>>> CS GPIO is not tested due to unavailability of necessary hardware setup.
>>>
>>> Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@....com>
>>> ---
>>> Hello @Stefen,
>>> We restructured the SPI core implementation, for handling arbitrary
>>> number of devices connected in parallel(multi-cs) or stacked mode. We
>>> have tested this updated patch on native-cs setup but couldn't test
>>> cs-gpio due to unavailability of a proper setup. If possible, could
>>> you please retest the cs-gpio use case with this updated patch and provide
>> your feedback.
>>
>> Hi,
>>
>> I tested this chain on 2 different systems using GPIOs as chip selects, and see
>> the same error on both:
>> [ 2.842045] pxa2xx-spi pxa2xx-spi.6: chipselect 0 already in use
>>
>> Let me know if you need any further testing.
>>
>> Thanks,
>>
>> Stefan Binding
>>
>>> ---
>>> drivers/spi/spi.c | 192 +++++++++++++++++++++++++++++++---------
>>> include/linux/spi/spi.h | 51 ++++++++---
>>> 2 files changed, 191 insertions(+), 52 deletions(-)
>>>
>>> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index
>>> 8ead7acb99f3..ff66147ba95f 100644
>>> --- a/drivers/spi/spi.c
>>> +++ b/drivers/spi/spi.c
>>> @@ -612,10 +612,21 @@ static int spi_dev_check(struct device *dev, void
>> *data)
>>> {
>>> struct spi_device *spi = to_spi_device(dev);
>>> struct spi_device *new_spi = data;
>>> -
>>> - if (spi->controller == new_spi->controller &&
>>> - spi_get_chipselect(spi, 0) == spi_get_chipselect(new_spi, 0))
>>> - return -EBUSY;
>>> + int idx, nw_idx;
>>> + u8 cs, cs_nw;
>>> +
>>> + if (spi->controller == new_spi->controller) {
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + cs = spi_get_chipselect(spi, idx);
>>> + for (nw_idx = 0; nw_idx < SPI_CS_CNT_MAX;
>> nw_idx++) {
>>> + cs_nw = spi_get_chipselect(spi, nw_idx);
> Thank you for dedicating your time to test my patch.
> As per my analysis the error is reported from here as we are
> supplying the former SPI device structure to retrieve the CS
> value for the new SPI devices.
> To fix this, could you kindly substitute the above line with
>
> cs_nw = spi_get_chipselect(new_spi, nw_idx);
>
> and rerun your tests?
> If it works correctly, I will incorporate this fix into my
> upcoming series.
>
> Regards,
> Amit
Hi,
I still see the same error:
[ 2.748546] pxa2xx-spi pxa2xx-spi.6: chipselect 0 already in use
Thanks,
Stefan
>
>>> + if (cs != 0xFF && cs_nw != 0xFF && cs ==
>> cs_nw) {
>>> + dev_err(dev, "chipselect %d already in
>> use\n", cs_nw);
>>> + return -EBUSY;
>>> + }
>>> + }
>>> + }
>>> + }
>>> return 0;
>>> }
>>>
>>> @@ -629,13 +640,32 @@ static int __spi_add_device(struct spi_device *spi)
>>> {
>>> struct spi_controller *ctlr = spi->controller;
>>> struct device *dev = ctlr->dev.parent;
>>> - int status;
>>> + int status, idx, nw_idx;
>>> + u8 cs, nw_cs;
>>> +
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + /* Chipselects are numbered 0..max; validate. */
>>> + cs = spi_get_chipselect(spi, idx);
>>> + if (cs != 0xFF && cs >= ctlr->num_chipselect) {
>>> + dev_err(dev, "cs%d >= max %d\n",
>> spi_get_chipselect(spi, idx),
>>> + ctlr->num_chipselect);
>>> + return -EINVAL;
>>> + }
>>> + }
>>>
>>> - /* Chipselects are numbered 0..max; validate. */
>>> - if (spi_get_chipselect(spi, 0) >= ctlr->num_chipselect) {
>>> - dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, 0),
>>> - ctlr->num_chipselect);
>>> - return -EINVAL;
>>> + /*
>>> + * Make sure that multiple logical CS doesn't map to the same
>> physical CS.
>>> + * For example, spi->chip_select[0] != spi->chip_select[1] and so on.
>>> + */
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + cs = spi_get_chipselect(spi, idx);
>>> + for (nw_idx = idx + 1; nw_idx < SPI_CS_CNT_MAX; nw_idx++) {
>>> + nw_cs = spi_get_chipselect(spi, nw_idx);
>>> + if (cs != 0xFF && nw_cs != 0xFF && cs == nw_cs) {
>>> + dev_err(dev, "chipselect %d already in use\n",
>> nw_cs);
>>> + return -EBUSY;
>>> + }
>>> + }
>>> }
>>>
>>> /* Set the bus ID string */
>>> @@ -647,11 +677,8 @@ static int __spi_add_device(struct spi_device *spi)
>>> * its configuration.
>>> */
>>> status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
>>> - if (status) {
>>> - dev_err(dev, "chipselect %d already in use\n",
>>> - spi_get_chipselect(spi, 0));
>>> + if (status)
>>> return status;
>>> - }
>>>
>>> /* Controller may unregister concurrently */
>>> if (IS_ENABLED(CONFIG_SPI_DYNAMIC) && @@ -659,8 +686,15 @@
>> static
>>> int __spi_add_device(struct spi_device *spi)
>>> return -ENODEV;
>>> }
>>>
>>> - if (ctlr->cs_gpiods)
>>> - spi_set_csgpiod(spi, 0, ctlr->cs_gpiods[spi_get_chipselect(spi,
>> 0)]);
>>> + if (ctlr->cs_gpiods) {
>>> + u8 cs;
>>> +
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + cs = spi_get_chipselect(spi, idx);
>>> + if (cs != 0xFF)
>>> + spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]);
>>> + }
>>> + }
>>>
>>> /*
>>> * Drivers may modify this initial i/o setup, but will @@ -701,6
>>> +735,9 @@ int spi_add_device(struct spi_device *spi)
>>> struct spi_controller *ctlr = spi->controller;
>>> int status;
>>>
>>> + /* Set the bus ID string */
>>> + spi_dev_set_name(spi);
>>> +
>>> mutex_lock(&ctlr->add_lock);
>>> status = __spi_add_device(spi);
>>> mutex_unlock(&ctlr->add_lock);
>>> @@ -942,32 +979,51 @@ static void spi_res_release(struct spi_controller
>> *ctlr, struct spi_message *mes
>>> }
>>>
>>>
>>> /*--------------------------------------------------------------------
>>> -----*/
>>> +static inline bool spi_is_last_cs(struct spi_device *spi) {
>>> + u8 idx;
>>> + bool last = false;
>>> +
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + if ((spi->cs_index_mask >> idx) & 0x01) {
>>> + if (spi->controller->last_cs[idx] ==
>> spi_get_chipselect(spi, idx))
>>> + last = true;
>>> + }
>>> + }
>>> + return last;
>>> +}
>>> +
>>>
>>> static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
>>> {
>>> bool activate = enable;
>>> + u8 idx;
>>>
>>> /*
>>> * Avoid calling into the driver (or doing delays) if the chip select
>>> * isn't actually changing from the last time this was called.
>>> */
>>> - if (!force && ((enable && spi->controller->last_cs ==
>> spi_get_chipselect(spi, 0)) ||
>>> - (!enable && spi->controller->last_cs !=
>> spi_get_chipselect(spi, 0))) &&
>>> + if (!force && ((enable && spi->controller->last_cs_index_mask == spi-
>>> cs_index_mask &&
>>> + spi_is_last_cs(spi)) ||
>>> + (!enable && spi->controller->last_cs_index_mask == spi-
>>> cs_index_mask &&
>>> + !spi_is_last_cs(spi))) &&
>>> (spi->controller->last_cs_mode_high == (spi->mode &
>> SPI_CS_HIGH)))
>>> return;
>>>
>>> trace_spi_set_cs(spi, activate);
>>>
>>> - spi->controller->last_cs = enable ? spi_get_chipselect(spi, 0) : -1;
>>> + spi->controller->last_cs_index_mask = spi->cs_index_mask;
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
>>> + spi->controller->last_cs[idx] = enable ? spi_get_chipselect(spi,
>> 0)
>>> +: -1;
>>> spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
>>>
>>> - if ((spi_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) &&
>> !activate)
>>> - spi_delay_exec(&spi->cs_hold, NULL);
>>> -
>>> if (spi->mode & SPI_CS_HIGH)
>>> enable = !enable;
>>>
>>> - if (spi_get_csgpiod(spi, 0)) {
>>> + if (spi_is_csgpiod(spi)) {
>>> + if (!spi->controller->set_cs_timing && !activate)
>>> + spi_delay_exec(&spi->cs_hold, NULL);
>>> +
>>> if (!(spi->mode & SPI_NO_CS)) {
>>> /*
>>> * Historically ACPI has no means of the GPIO polarity
>> and @@
>>> -979,26 +1035,38 @@ static void spi_set_cs(struct spi_device *spi, bool
>> enable, bool force)
>>> * ambiguity. That's why we use enable, that takes
>> SPI_CS_HIGH
>>> * into account.
>>> */
>>> - if (has_acpi_companion(&spi->dev))
>>> -
>> gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), !enable);
>>> - else
>>> - /* Polarity handled by GPIO library */
>>> -
>> gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), activate);
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + if (((spi->cs_index_mask >> idx) & 0x01) &&
>>> + spi_get_csgpiod(spi, idx)) {
>>> + if (has_acpi_companion(&spi->dev))
>>> +
>> gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx),
>>> +
>> !enable);
>>> + else
>>> + /* Polarity handled by GPIO
>> library */
>>> +
>> gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx),
>>> +
>> activate);
>>> +
>>> + if (activate)
>>> + spi_delay_exec(&spi-
>>> cs_setup, NULL);
>>> + else
>>> + spi_delay_exec(&spi-
>>> cs_inactive, NULL);
>>> + }
>>> + }
>>> }
>>> /* Some SPI masters need both GPIO CS & slave_select */
>>> if ((spi->controller->flags & SPI_CONTROLLER_GPIO_SS) &&
>>> spi->controller->set_cs)
>>> spi->controller->set_cs(spi, !enable);
>>> +
>>> + if (!spi->controller->set_cs_timing) {
>>> + if (activate)
>>> + spi_delay_exec(&spi->cs_setup, NULL);
>>> + else
>>> + spi_delay_exec(&spi->cs_inactive, NULL);
>>> + }
>>> } else if (spi->controller->set_cs) {
>>> spi->controller->set_cs(spi, !enable);
>>> }
>>> -
>>> - if (spi_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) {
>>> - if (activate)
>>> - spi_delay_exec(&spi->cs_setup, NULL);
>>> - else
>>> - spi_delay_exec(&spi->cs_inactive, NULL);
>>> - }
>>> }
>>>
>>> #ifdef CONFIG_HAS_DMA
>>> @@ -2222,8 +2290,8 @@ static void of_spi_parse_dt_cs_delay(struct
>> device_node *nc,
>>> static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
>>> struct device_node *nc)
>>> {
>>> - u32 value;
>>> - int rc;
>>> + u32 value, cs[SPI_CS_CNT_MAX];
>>> + int rc, idx;
>>>
>>> /* Mode (clock phase/polarity/etc.) */
>>> if (of_property_read_bool(nc, "spi-cpha")) @@ -2295,14 +2363,52
>> @@
>>> static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
>>> return 0;
>>> }
>>>
>>> + if (ctlr->num_chipselect > SPI_CS_CNT_MAX) {
>>> + dev_err(&ctlr->dev, "No. of CS is more than max. no. of
>> supported CS\n");
>>> + return -EINVAL;
>>> + }
>>> +
>>> + /*
>>> + * Zero(0) is a valid physical CS value and can be located at any
>>> + * logical CS in the spi->chip_select[]. If all the physical CS
>>> + * are initialized to 0 then It would be difficult to differentiate
>>> + * between a valid physical CS 0 & an unused logical CS whose
>> physical
>>> + * CS can be 0. As a solution to this issue initialize all the CS to 0xFF.
>>> + * Now all the unused logical CS will have 0xFF physical CS value & can
>> be
>>> + * ignore while performing physical CS validity checks.
>>> + */
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
>>> + spi_set_chipselect(spi, idx, 0xFF);
>>> +
>>> /* Device address */
>>> - rc = of_property_read_u32(nc, "reg", &value);
>>> - if (rc) {
>>> + rc = of_property_read_variable_u32_array(nc, "reg", &cs[0], 1,
>>> + SPI_CS_CNT_MAX);
>>> + if (rc < 0) {
>>> dev_err(&ctlr->dev, "%pOF has no valid 'reg' property
>> (%d)\n",
>>> nc, rc);
>>> return rc;
>>> }
>>> - spi_set_chipselect(spi, 0, value);
>>> + if (rc > ctlr->num_chipselect) {
>>> + dev_err(&ctlr->dev, "%pOF has number of CS > ctlr-
>>> num_chipselect (%d)\n",
>>> + nc, rc);
>>> + return rc;
>>> + }
>>> + if ((of_property_read_bool(nc, "parallel-memories")) &&
>>> + (!(ctlr->flags & SPI_CONTROLLER_MULTI_CS))) {
>>> + dev_err(&ctlr->dev, "SPI controller doesn't support multi
>> CS\n");
>>> + return -EINVAL;
>>> + }
>>> + for (idx = 0; idx < rc; idx++)
>>> + spi_set_chipselect(spi, idx, cs[idx]);
>>> +
>>> + /* spi->chip_select[i] gives the corresponding physical CS for logical CS
>> i
>>> + * logical CS number is represented by setting the ith bit in spi-
>>> cs_index_mask
>>> + * So, for example, if spi->cs_index_mask = 0x01 then logical CS
>> number is 0 and
>>> + * spi->chip_select[0] will give the physical CS.
>>> + * By default spi->chip_select[0] will hold the physical CS number so,
>> set
>>> + * spi->cs_index_mask as 0x01.
>>> + */
>>> + spi->cs_index_mask = 0x01;
>>>
>>> /* Device speed */
>>> if (!of_property_read_u32(nc, "spi-max-frequency", &value)) @@
>>> -3100,6 +3206,7 @@ int spi_register_controller(struct spi_controller *ctlr)
>>> struct boardinfo *bi;
>>> int first_dynamic;
>>> int status;
>>> + int idx;
>>>
>>> if (!dev)
>>> return -ENODEV;
>>> @@ -3164,7 +3271,8 @@ int spi_register_controller(struct spi_controller
>> *ctlr)
>>> }
>>>
>>> /* Setting last_cs to -1 means no chip selected */
>>> - ctlr->last_cs = -1;
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
>>> + ctlr->last_cs[idx] = -1;
>>>
>>> status = device_add(&ctlr->dev);
>>> if (status < 0)
>>> @@ -3889,7 +3997,7 @@ static int __spi_validate(struct spi_device *spi,
>> struct spi_message *message)
>>> * cs_change is set for each transfer.
>>> */
>>> if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits &
>> SPI_CS_WORD) ||
>>> - spi_get_csgpiod(spi, 0))) {
>>> + spi_is_csgpiod(spi))) {
>>> size_t maxsize = BITS_TO_BYTES(spi->bits_per_word);
>>> int ret;
>>>
>>> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index
>>> 7b4baff63c5c..871d3a6d879b 100644
>>> --- a/include/linux/spi/spi.h
>>> +++ b/include/linux/spi/spi.h
>>> @@ -20,6 +20,9 @@
>>>
>>> #include <uapi/linux/spi/spi.h>
>>>
>>> +/* Max no. of CS supported per spi device */ #define SPI_CS_CNT_MAX 4
>>> +
>>> struct dma_chan;
>>> struct software_node;
>>> struct ptp_system_timestamp;
>>> @@ -132,7 +135,8 @@ extern void
>> spi_transfer_cs_change_delay_exec(struct spi_message *msg,
>>> * @max_speed_hz: Maximum clock rate to be used with this chip
>>> * (on this board); may be changed by the device's driver.
>>> * The spi_transfer.speed_hz can override this for each transfer.
>>> - * @chip_select: Chipselect, distinguishing chips handled by @controller.
>>> + * @chip_select: Array of physical chipselect, spi->chipselect[i] gives
>>> + * the corresponding physical CS for logical CS i.
>>> * @mode: The spi mode defines how data is clocked out and in.
>>> * This may be changed by the device's driver.
>>> * The "active low" default for chipselect mode can be overridden
>>> @@ -157,8 +161,8 @@ extern void
>> spi_transfer_cs_change_delay_exec(struct spi_message *msg,
>>> * the device will bind to the named driver and only the named driver.
>>> * Do not set directly, because core frees it; use driver_set_override() to
>>> * set or clear it.
>>> - * @cs_gpiod: GPIO descriptor of the chipselect line (optional, NULL when
>>> - * not using a GPIO line)
>>> + * @cs_gpiod: Array of GPIO descriptors of the corresponding chipselect
>> lines
>>> + * (optional, NULL when not using a GPIO line)
>>> * @word_delay: delay to be inserted between consecutive
>>> * words of a transfer
>>> * @cs_setup: delay to be introduced by the controller after CS is
>>> asserted @@ -167,6 +171,7 @@ extern void
>> spi_transfer_cs_change_delay_exec(struct spi_message *msg,
>>> * deasserted. If @cs_change_delay is used from @spi_transfer, then
>> the
>>> * two delays will be added up.
>>> * @pcpu_statistics: statistics for the spi_device
>>> + * @cs_index_mask: Bit mask of the active chipselect(s) in the
>>> + chipselect array
>>> *
>>> * A @spi_device is used to interchange data between an SPI slave
>>> * (usually a discrete chip) and CPU memory.
>>> @@ -182,7 +187,7 @@ struct spi_device {
>>> struct spi_controller *controller;
>>> struct spi_controller *master; /* Compatibility layer */
>>> u32 max_speed_hz;
>>> - u8 chip_select;
>>> + u8 chip_select[SPI_CS_CNT_MAX];
>>> u8 bits_per_word;
>>> bool rt;
>>> #define SPI_NO_TX BIT(31) /* No transmit wire */
>>> @@ -213,7 +218,7 @@ struct spi_device {
>>> void *controller_data;
>>> char modalias[SPI_NAME_SIZE];
>>> const char *driver_override;
>>> - struct gpio_desc *cs_gpiod; /* Chip select GPIO descriptor
>> */
>>> + struct gpio_desc *cs_gpiod[SPI_CS_CNT_MAX]; /* Chip select
>> gpio desc */
>>> struct spi_delay word_delay; /* Inter-word delay */
>>> /* CS delays */
>>> struct spi_delay cs_setup;
>>> @@ -223,6 +228,13 @@ struct spi_device {
>>> /* The statistics */
>>> struct spi_statistics __percpu *pcpu_statistics;
>>>
>>> + /* Bit mask of the chipselect(s) that the driver need to use from
>>> + * the chipselect array.When the controller is capable to handle
>>> + * multiple chip selects & memories are connected in parallel
>>> + * then more than one bit need to be set in cs_index_mask.
>>> + */
>>> + u32 cs_index_mask : SPI_CS_CNT_MAX;
>>> +
>>> /*
>>> * Likely need more hooks for more protocol options affecting how
>>> * the controller talks to each chip, like:
>>> @@ -279,22 +291,33 @@ static inline void *spi_get_drvdata(const struct
>>> spi_device *spi)
>>>
>>> static inline u8 spi_get_chipselect(const struct spi_device *spi, u8 idx)
>>> {
>>> - return spi->chip_select;
>>> + return spi->chip_select[idx];
>>> }
>>>
>>> static inline void spi_set_chipselect(struct spi_device *spi, u8 idx, u8
>> chipselect)
>>> {
>>> - spi->chip_select = chipselect;
>>> + spi->chip_select[idx] = chipselect;
>>> }
>>>
>>> static inline struct gpio_desc *spi_get_csgpiod(const struct spi_device *spi,
>> u8 idx)
>>> {
>>> - return spi->cs_gpiod;
>>> + return spi->cs_gpiod[idx];
>>> }
>>>
>>> static inline void spi_set_csgpiod(struct spi_device *spi, u8 idx, struct
>> gpio_desc *csgpiod)
>>> {
>>> - spi->cs_gpiod = csgpiod;
>>> + spi->cs_gpiod[idx] = csgpiod;
>>> +}
>>> +
>>> +static inline bool spi_is_csgpiod(struct spi_device *spi) {
>>> + u8 idx;
>>> +
>>> + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
>>> + if (spi_get_csgpiod(spi, idx))
>>> + return true;
>>> + }
>>> + return false;
>>> }
>>>
>>> /**
>>> @@ -399,6 +422,8 @@ extern struct spi_device
>> *spi_new_ancillary_device(struct spi_device *spi, u8 ch
>>> * @bus_lock_spinlock: spinlock for SPI bus locking
>>> * @bus_lock_mutex: mutex for exclusion of multiple callers
>>> * @bus_lock_flag: indicates that the SPI bus is locked for
>>> exclusive use
>>> + * @multi_cs_cap: indicates that the SPI Controller can assert/de-assert
>>> + * more than one chip select at once.
>>> * @setup: updates the device mode and clocking records used by a
>>> * device's SPI controller; protocol code may call this. This
>>> * must fail if an unrecognized or unsupported mode is requested.
>>> @@ -567,6 +592,11 @@ struct spi_controller {
>>> #define SPI_CONTROLLER_MUST_TX BIT(4) /* Requires tx */
>>> #define SPI_CONTROLLER_GPIO_SS BIT(5) /* GPIO CS must
>> select slave */
>>> #define SPI_CONTROLLER_SUSPENDED BIT(6) /* Currently
>> suspended */
>>> + /*
>>> + * The spi-controller has multi chip select capability and can
>>> + * assert/de-assert more than one chip select at once.
>>> + */
>>> +#define SPI_CONTROLLER_MULTI_CS BIT(7)
>>>
>>> /* Flag indicating if the allocation of this struct is devres-managed */
>>> bool devm_allocated;
>>> @@ -677,7 +707,8 @@ struct spi_controller {
>>> bool rt;
>>> bool auto_runtime_pm;
>>> bool cur_msg_mapped;
>>> - char last_cs;
>>> + char last_cs[SPI_CS_CNT_MAX];
>>> + char last_cs_index_mask;
>>> bool last_cs_mode_high;
>>> bool fallback;
>>> struct completion xfer_completion;
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