---
drivers/spi/spi.c | 231 ++++++++++++++++++++++++++++------------
include/linux/spi/spi.h | 32 ++++--
2 files changed, 189 insertions(+), 74 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 9291b2a0e887..a793e56f6a21 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -612,10 +612,24 @@ static int spi_dev_check(struct device *dev, void *data)
{
struct spi_device *spi = to_spi_device(dev);
struct spi_device *new_spi = data;
+ int idx, nw_idx;
- if (spi->controller == new_spi->controller &&
- spi_get_chipselect(spi, 0) == spi_get_chipselect(new_spi, 0))
- return -EBUSY;
+ if (spi->controller == new_spi->controller) {
+ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
+ for (nw_idx = 0; nw_idx < SPI_CS_CNT_MAX; nw_idx++) {
+ if ((idx != 0 && !spi_get_chipselect(spi, idx)) ||
+ (nw_idx != 0 && !spi_get_chipselect(spi, nw_idx))) {
+ continue;
+ } else if (spi_get_chipselect(spi, idx) ==
+ spi_get_chipselect(new_spi, nw_idx)) {
+ dev_err(dev,
+ "chipselect %d already in use\n",
+ spi_get_chipselect(new_spi, nw_idx));
+ return -EBUSY;
+ }
+ }
+ }
+ }
return 0;
}
@@ -629,7 +643,7 @@ 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;
/*
* We need to make sure there's no other device with this
@@ -638,8 +652,6 @@ static int __spi_add_device(struct spi_device *spi)
*/
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));
return status;
}
@@ -649,8 +661,13 @@ 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) {
+ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
+ if (!(idx != 0 && !spi_get_chipselect(spi, idx)))
+ spi_set_csgpiod(spi, idx,
+ ctlr->cs_gpiods[spi_get_chipselect(spi, idx)]);
+ }
+ }
/*
* Drivers may modify this initial i/o setup, but will
@@ -690,13 +707,15 @@ 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;
- /* 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;
+ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
+ /* Chipselects are numbered 0..max; validate. */
+ if (spi_get_chipselect(spi, idx) >= ctlr->num_chipselect) {
+ dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx),
+ ctlr->num_chipselect);
+ return -EINVAL;
+ }
}
/* Set the bus ID string */
@@ -713,12 +732,15 @@ static int spi_add_device_locked(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
struct device *dev = ctlr->dev.parent;
+ int idx;
- /* 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;
+ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
+ /* Chipselects are numbered 0..max; validate. */
+ if (spi_get_chipselect(spi, idx) >= ctlr->num_chipselect) {
+ dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx),
+ ctlr->num_chipselect);
+ return -EINVAL;
+ }
}
/* Set the bus ID string */
@@ -966,58 +988,122 @@ static void spi_res_release(struct spi_controller *ctlr, struct spi_message *mes
static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
{
bool activate = enable;
+ u32 cs_num = 0;
+ int idx;
/*
- * Avoid calling into the driver (or doing delays) if the chip select
- * isn't actually changing from the last time this was called.
+ * In parallel mode all the chip selects are asserted/de-asserted
+ * at once
*/
- if (!force && ((enable && spi->controller->last_cs == spi_get_chipselect(spi, 0)) ||
- (!enable && spi->controller->last_cs != spi_get_chipselect(spi, 0))) &&
- (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
- return;
-
- trace_spi_set_cs(spi, activate);
+ if ((spi->cs_index_mask & SPI_PARALLEL_CS_MASK) == SPI_PARALLEL_CS_MASK) {
+ 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) && spi_get_csgpiod(spi, 1)) {
+ if (!(spi->mode & SPI_NO_CS)) {
+ /*
+ * Historically ACPI has no means of the GPIO polarity and
+ * thus the SPISerialBus() resource defines it on the per-chip
+ * basis. In order to avoid a chain of negations, the GPIO
+ * polarity is considered being Active High. Even for the cases
+ * when _DSD() is involved (in the updated versions of ACPI)
+ * the GPIO CS polarity must be defined Active High to avoid
+ * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
+ * into account.
+ */
+ if (has_acpi_companion(&spi->dev)) {
+ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
+ gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx),
+ !enable);
+ } else {
+ for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
+ /* Polarity handled by GPIO library */
+ gpiod_set_value_cansleep(spi_get_csgpiod(spi, idx),
+ activate);
+ }
+ }
+ /* Some SPI masters need both GPIO CS & slave_select */
+ if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
+ spi->controller->set_cs)
+ spi->controller->set_cs(spi, !enable);
+ } else if (spi->controller->set_cs) {
+ spi->controller->set_cs(spi, !enable);
+ }
- spi->controller->last_cs = 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_get_csgpiod(spi, 1) ||
+ !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_get_csgpiod(spi, 0) || !spi->controller->set_cs_timing) && !activate)
- spi_delay_exec(&spi->cs_hold, NULL);
+ if (spi->cs_index_mask)
+ cs_num = ffs(spi->cs_index_mask) - 1;
- if (spi->mode & SPI_CS_HIGH)
- enable = !enable;
+ /*
+ * 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, cs_num)) ||
+ (!enable && spi->controller->last_cs !=
+ spi_get_chipselect(spi, cs_num))) &&
+ (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, cs_num) : -1;
+ spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
+
+ if ((spi_get_csgpiod(spi, cs_num) || !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, cs_num)) {
+ if (!(spi->mode & SPI_NO_CS)) {
+ /*
+ * Historically ACPI has no means of the GPIO polarity and
+ * thus the SPISerialBus() resource defines it on the per-chip
+ * basis. In order to avoid a chain of negations, the GPIO
+ * polarity is considered being Active High. Even for the cases
+ * when _DSD() is involved (in the updated versions of ACPI)
+ * the GPIO CS polarity must be defined Active High to avoid
+ * 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, cs_num),
+ !enable);
+ else
+ /* Polarity handled by GPIO library */
+ gpiod_set_value_cansleep(spi_get_csgpiod(spi, cs_num),
+ activate);
+ }
+ /* Some SPI masters need both GPIO CS & slave_select */
+ if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
+ spi->controller->set_cs)
+ spi->controller->set_cs(spi, !enable);
+ } else if (spi->controller->set_cs) {
+ spi->controller->set_cs(spi, !enable);
+ }
- if (spi_get_csgpiod(spi, 0)) {
- if (!(spi->mode & SPI_NO_CS)) {
- /*
- * Historically ACPI has no means of the GPIO polarity and
- * thus the SPISerialBus() resource defines it on the per-chip
- * basis. In order to avoid a chain of negations, the GPIO
- * polarity is considered being Active High. Even for the cases
- * when _DSD() is involved (in the updated versions of ACPI)
- * the GPIO CS polarity must be defined Active High to avoid
- * 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);
+ if (spi_get_csgpiod(spi, cs_num) || !spi->controller->set_cs_timing) {
+ if (activate)
+ spi_delay_exec(&spi->cs_setup, NULL);
else
- /* Polarity handled by GPIO library */
- gpiod_set_value_cansleep(spi_get_csgpiod(spi, 0), activate);
+ spi_delay_exec(&spi->cs_inactive, NULL);
}
- /* Some SPI masters need both GPIO CS & slave_select */
- if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
- spi->controller->set_cs)
- spi->controller->set_cs(spi, !enable);
- } 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);
}
}
@@ -2246,8 +2332,8 @@ 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] = {0};
+ int rc, idx;
/* Mode (clock phase/polarity/etc.) */
if (of_property_read_bool(nc, "spi-cpha"))
@@ -2320,13 +2406,21 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
}
/* 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 || rc > ctlr->num_chipselect) {
dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
nc, rc);
return rc;
+ } else 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;
}
- spi_set_chipselect(spi, 0, value);
+ for (idx = 0; idx < rc; idx++)
+ spi_set_chipselect(spi, idx, cs[idx]);
+ /* By default set the spi->cs_index_mask as 1 */
+ spi->cs_index_mask = 0x01;
/* Device speed */
if (!of_property_read_u32(nc, "spi-max-frequency", &value))
@@ -3905,7 +3999,8 @@ 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_get_csgpiod(spi, 0) ||
+ spi_get_csgpiod(spi, 1))) {
size_t maxsize;
int ret;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index cfe42f8cd7a4..d0f9a9a8b6d8 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -19,6 +19,11 @@
#include <linux/acpi.h>
#include <linux/u64_stats_sync.h>
+/* Max no. of CS supported per spi device */
+#define SPI_CS_CNT_MAX 2
+
+/* chip select mask */
+#define SPI_PARALLEL_CS_MASK (BIT(0) | BIT(1))
struct dma_chan;
struct software_node;
struct ptp_system_timestamp;
@@ -166,6 +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.
@@ -181,7 +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 */
@@ -212,7 +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 desc */
+ 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;
@@ -222,6 +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:
@@ -278,22 +291,22 @@ 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;
}
/**
@@ -398,6 +411,8 @@ 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.
@@ -564,6 +579,11 @@ struct spi_controller {
#define SPI_CONTROLLER_MUST_TX BIT(4) /* Requires tx */
#define SPI_MASTER_GPIO_SS BIT(5) /* GPIO CS must select slave */
+ /*
+ * 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(6)
/* Flag indicating if the allocation of this struct is devres-managed */
bool devm_allocated;
