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authorMark Brown <broonie@kernel.org>2023-12-07 20:20:35 +0000
committerMark Brown <broonie@kernel.org>2023-12-07 20:20:35 +0000
commit88a50c1663ffa9f6b31705c6bf7a887a2c8d9434 (patch)
tree77e9b65ad3b670133c14c9b8a90ec3b3ce471443 /drivers/spi
parent18f78b5e609b19b56237f0dae47068d44b8b0ecd (diff)
parent4d8ff6b0991d5e86b17b235fc46ec62e9195cb9b (diff)
spi: Add support for stacked/parallel memories
Merge series from Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>: This patch series adds support to the SPI framework for using multiple chip selects.
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi.c259
1 files changed, 217 insertions, 42 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a4b8c07c5951..7477a11e12be 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(new_spi, nw_idx);
+ 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);
@@ -727,6 +764,7 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr,
{
struct spi_device *proxy;
int status;
+ u8 idx;
/*
* NOTE: caller did any chip->bus_num checks necessary.
@@ -742,6 +780,18 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr,
WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
+ /*
+ * 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(proxy, idx, 0xFF);
+
spi_set_chipselect(proxy, 0, chip->chip_select);
proxy->max_speed_hz = chip->max_speed_hz;
proxy->mode = chip->mode;
@@ -750,6 +800,15 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr,
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL;
+ /*
+ * 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.
+ */
+ proxy->cs_index_mask = 0x01;
if (chip->swnode) {
status = device_add_software_node(&proxy->dev, chip->swnode);
@@ -942,32 +1001,51 @@ 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 +1057,38 @@ 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
@@ -2225,8 +2315,8 @@ 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"))
@@ -2298,14 +2388,53 @@ 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))
@@ -2411,6 +2540,7 @@ struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
struct spi_controller *ctlr = spi->controller;
struct spi_device *ancillary;
int rc = 0;
+ u8 idx;
/* Alloc an spi_device */
ancillary = spi_alloc_device(ctlr);
@@ -2421,12 +2551,33 @@ struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
+ /*
+ * 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(ancillary, idx, 0xFF);
+
/* Use provided chip-select for ancillary device */
spi_set_chipselect(ancillary, 0, chip_select);
/* Take over SPI mode/speed from SPI main device */
ancillary->max_speed_hz = spi->max_speed_hz;
ancillary->mode = spi->mode;
+ /*
+ * 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.
+ */
+ ancillary->cs_index_mask = 0x01;
WARN_ON(!mutex_is_locked(&ctlr->add_lock));
@@ -2629,6 +2780,7 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
struct acpi_spi_lookup lookup = {};
struct spi_device *spi;
int ret;
+ u8 idx;
if (!ctlr && index == -1)
return ERR_PTR(-EINVAL);
@@ -2664,12 +2816,33 @@ struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
return ERR_PTR(-ENOMEM);
}
+ /*
+ * 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);
+
ACPI_COMPANION_SET(&spi->dev, adev);
spi->max_speed_hz = lookup.max_speed_hz;
spi->mode |= lookup.mode;
spi->irq = lookup.irq;
spi->bits_per_word = lookup.bits_per_word;
spi_set_chipselect(spi, 0, lookup.chip_select);
+ /*
+ * 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;
return spi;
}
@@ -3103,6 +3276,7 @@ int spi_register_controller(struct spi_controller *ctlr)
struct boardinfo *bi;
int first_dynamic;
int status;
+ int idx;
if (!dev)
return -ENODEV;
@@ -3167,7 +3341,8 @@ 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)
@@ -3892,7 +4067,7 @@ 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;