spi: spi-ath79: support multiple internal chip select lines

Several devices with multiple flash chips use the internal chip select
lines. Don't assume that chip select 1 and above are GPIO lines.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c
index f369174..3e9b928 100644 (file)
--- a/drivers/spi/spi-ath79.c
+++ b/drivers/spi/spi-ath79.c
@@ -78,14 +78,16 @@ static void ath79_spi_chipselect(struct spi_device *spi, int is_active)
                ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
        }
 
-       if (spi->chip_select) {
+       if (gpio_is_valid(spi->cs_gpio)) {
                /* SPI is normally active-low */
                gpio_set_value(spi->cs_gpio, cs_high);
        } else {
+               u32 cs_bit = AR71XX_SPI_IOC_CS(spi->chip_select);
+
                if (cs_high)
-                       sp->ioc_base |= AR71XX_SPI_IOC_CS0;
+                       sp->ioc_base |= cs_bit;
                else
-                       sp->ioc_base &= ~AR71XX_SPI_IOC_CS0;
+                       sp->ioc_base &= ~cs_bit;
 
                ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
        }
@@ -118,11 +120,8 @@ static int ath79_spi_setup_cs(struct spi_device *spi)
        struct ath79_spi *sp = ath79_spidev_to_sp(spi);
        int status;
 
-       if (spi->chip_select && !gpio_is_valid(spi->cs_gpio))
-               return -EINVAL;
-
        status = 0;
-       if (spi->chip_select) {
+       if (gpio_is_valid(spi->cs_gpio)) {
                unsigned long flags;
 
                flags = GPIOF_DIR_OUT;
@@ -134,10 +133,12 @@ static int ath79_spi_setup_cs(struct spi_device *spi)
                status = gpio_request_one(spi->cs_gpio, flags,
                                          dev_name(&spi->dev));
        } else {
+               u32 cs_bit = AR71XX_SPI_IOC_CS(spi->chip_select);
+
                if (spi->mode & SPI_CS_HIGH)
-                       sp->ioc_base &= ~AR71XX_SPI_IOC_CS0;
+                       sp->ioc_base &= ~cs_bit;
                else
-                       sp->ioc_base |= AR71XX_SPI_IOC_CS0;
+                       sp->ioc_base |= cs_bit;
 
                ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
        }
@@ -147,7 +148,7 @@ static int ath79_spi_setup_cs(struct spi_device *spi)
 
 static void ath79_spi_cleanup_cs(struct spi_device *spi)
 {
-       if (spi->chip_select) {
+       if (gpio_is_valid(spi->cs_gpio)) {
                gpio_free(spi->cs_gpio);
        }
 }