+ 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;
