Unverified Commit be84be4a authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Mark Brown
Browse files

spi: Introduce SPI_INVALID_CS and is_valid_cs() 



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: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://msgid.link/r/20240307150256.3789138-4-andriy.shevchenko@linux.intel.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 14fe5a98

drivers/spi/spi.c

+23 −16
Original line number Diff line number Diff line
@@ -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)