From: Jonas Gorski Date: Mon, 15 Sep 2025 18:37:20 +0000 (+0200) Subject: spi: keep track of number of chipselects in spi_device X-Git-Tag: v6.18-rc1~165^2~2^2~5 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=099f942182e3695554cba44e4bafb08a4111b50f;p=thirdparty%2Fkernel%2Flinux.git spi: keep track of number of chipselects in spi_device There are several places where we need to iterate over a device's chipselect. To be able to do it efficiently, store the number of chipselects in spi_device, like we do for controllers. Since we now use a device supplied value, add a check to make sure it isn't more than we can support. Signed-off-by: Jonas Gorski Link: https://patch.msgid.link/20250915183725.219473-3-jonas.gorski@gmail.com Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b07d6cdf587ce..6598fb862d80a 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -586,6 +586,7 @@ struct spi_device *spi_alloc_device(struct spi_controller *ctlr) spi->dev.bus = &spi_bus_type; spi->dev.release = spidev_release; spi->mode = ctlr->buswidth_override_bits; + spi->num_chipselect = 1; device_initialize(&spi->dev); return spi; @@ -635,7 +636,7 @@ static inline int spi_dev_check_cs(struct device *dev, u8 idx_new; cs = spi_get_chipselect(spi, idx); - for (idx_new = new_idx; idx_new < SPI_CS_CNT_MAX; idx_new++) { + for (idx_new = new_idx; idx_new < new_spi->num_chipselect; idx_new++) { cs_new = spi_get_chipselect(new_spi, idx_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); @@ -652,7 +653,7 @@ static int spi_dev_check(struct device *dev, void *data) int status, idx; if (spi->controller == new_spi->controller) { - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + for (idx = 0; idx < spi->num_chipselect; idx++) { status = spi_dev_check_cs(dev, spi, idx, new_spi, 0); if (status) return status; @@ -674,7 +675,13 @@ static int __spi_add_device(struct spi_device *spi) int status, idx; u8 cs; - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + if (spi->num_chipselect > SPI_CS_CNT_MAX) { + dev_err(dev, "num_cs %d > max %d\n", spi->num_chipselect, + SPI_CS_CNT_MAX); + return -EOVERFLOW; + } + + for (idx = 0; idx < spi->num_chipselect; idx++) { /* Chipselects are numbered 0..max; validate. */ cs = spi_get_chipselect(spi, idx); if (is_valid_cs(cs) && cs >= ctlr->num_chipselect) { @@ -689,7 +696,7 @@ static int __spi_add_device(struct spi_device *spi) * For example, spi->chip_select[0] != spi->chip_select[1] and so on. */ if (!spi_controller_is_target(ctlr)) { - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + for (idx = 0; idx < spi->num_chipselect; idx++) { status = spi_dev_check_cs(dev, spi, idx, spi, idx + 1); if (status) return status; @@ -717,7 +724,7 @@ static int __spi_add_device(struct spi_device *spi) if (ctlr->cs_gpiods) { u8 cs; - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + for (idx = 0; idx < spi->num_chipselect; idx++) { cs = spi_get_chipselect(spi, idx); if (is_valid_cs(cs)) spi_set_csgpiod(spi, idx, ctlr->cs_gpiods[cs]); @@ -1024,7 +1031,7 @@ static void spi_res_release(struct spi_controller *ctlr, struct spi_message *mes /*-------------------------------------------------------------------------*/ #define spi_for_each_valid_cs(spi, idx) \ - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) \ + for (idx = 0; idx < spi->num_chipselect; idx++) \ if (!(spi->cs_index_mask & BIT(idx))) {} else static inline bool spi_is_last_cs(struct spi_device *spi) @@ -1080,8 +1087,12 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force) trace_spi_set_cs(spi, activate); 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) : SPI_INVALID_CS; + for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + if (enable && idx < spi->num_chipselect) + spi->controller->last_cs[idx] = spi_get_chipselect(spi, 0); + else + spi->controller->last_cs[idx] = SPI_INVALID_CS; + } spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH; if (spi->controller->last_cs_mode_high) @@ -2452,6 +2463,8 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, dev_err(&ctlr->dev, "SPI controller doesn't support multi CS\n"); return -EINVAL; } + + spi->num_chipselect = rc; for (idx = 0; idx < rc; idx++) spi_set_chipselect(spi, idx, cs[idx]); diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index e9ea43234d9a8..49c048277e979 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -170,6 +170,7 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg, * two delays will be added up. * @chip_select: Array of physical chipselect, spi->chipselect[i] gives * the corresponding physical CS for logical CS i. + * @num_chipselect: Number of physical chipselects used. * @cs_index_mask: Bit mask of the active chipselect(s) in the chipselect array * @cs_gpiod: Array of GPIO descriptors of the corresponding chipselect lines * (optional, NULL when not using a GPIO line) @@ -229,6 +230,7 @@ struct spi_device { struct spi_delay cs_inactive; u8 chip_select[SPI_CS_CNT_MAX]; + u8 num_chipselect; /* * Bit mask of the chipselect(s) that the driver need to use from @@ -315,7 +317,7 @@ static inline bool spi_is_csgpiod(struct spi_device *spi) { u8 idx; - for (idx = 0; idx < SPI_CS_CNT_MAX; idx++) { + for (idx = 0; idx < spi->num_chipselect; idx++) { if (spi_get_csgpiod(spi, idx)) return true; }