@@ -608,6 +608,22 @@ static void spi_dev_set_name(struct spi_device *spi)
spi_get_chipselect(spi, 0));
}
+/*
+ * 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 -1.
+ * Now all the unused logical CS will have -1 physical CS value & can be
+ * ignored while performing physical CS validity checks.
+ */
+#define SPI_INVALID_CS ((s8)-1)
+
+static inline bool is_valid_cs(s8 chip_select)
+{
+ return chip_select != SPI_INVALID_CS;
+}
+
static inline int spi_dev_check_cs(struct device *dev,
struct spi_device *spi, u8 idx,
struct spi_device *new_spi, u8 new_idx)
@@ -618,7 +634,7 @@ static inline int spi_dev_check_cs(struct device *dev,
cs = spi_get_chipselect(spi, idx);
for (idx_new = new_idx; idx_new < SPI_CS_CNT_MAX; idx_new++) {
cs_new = spi_get_chipselect(new_spi, idx_new);
- if (cs != 0xFF && cs_new != 0xFF && cs == cs_new) {
+ if (is_valid_cs(cs) && is_valid_cs(cs_new) && cs == cs_new) {
dev_err(dev, "chipselect %u already in use\n", cs_new);
return -EBUSY;
}
@@ -658,7 +674,7 @@ static int __spi_add_device(struct spi_device *spi)
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) {
+ if (is_valid_cs(cs) && cs >= ctlr->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n", spi_get_chipselect(spi, idx),
ctlr->num_chipselect);
return -EINVAL;
@@ -698,7 +714,7 @@ static int __spi_add_device(struct spi_device *spi)
for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) {
cs = spi_get_chipselect(spi, idx);
- if (cs != 0xFF)
+ if (is_valid_cs(cs))
spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]);
}
}
@@ -756,17 +772,8 @@ static void spi_set_all_cs_unused(struct spi_device *spi)
{
u8 idx;
- /*
- * 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);
+ spi_set_chipselect(spi, idx, SPI_INVALID_CS);
}
/**
@@ -1050,7 +1057,7 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
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[idx] = enable ? spi_get_chipselect(spi, 0) : SPI_INVALID_CS;
spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
if (spi->mode & SPI_CS_HIGH)
@@ -3333,9 +3340,9 @@ int spi_register_controller(struct spi_controller *ctlr)
goto free_bus_id;
}
- /* Setting last_cs to -1 means no chip selected */
+ /* Setting last_cs to SPI_INVALID_CS means no chip selected */
for (idx = 0; idx < SPI_CS_CNT_MAX; idx++)
- ctlr->last_cs[idx] = -1;
+ ctlr->last_cs[idx] = SPI_INVALID_CS;
status = device_add(&ctlr->dev);
if (status < 0)
The SPI core inconsistently uses the marker value for unused chip select pin. Define a constant (with appropriate type) and introduce is_valid_cs() helper function to avoid spreading this inconsistency in the future. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- drivers/spi/spi.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-)