target/linux/bcm27xx/patches-5.10/950-0595-spi-bcm2835-Increase-the-CS-limit-to-24.patch

   1 From c3fbb1e6771dabb14571552c036a049ffa470eb1 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Fri, 30 Apr 2021 08:34:36 +0100
   4 Subject: [PATCH] spi: bcm2835: Increase the CS limit to 24
   5
   6 Increase the maximum number of CS lines to 24, and ensure this limit is
   7 not exceeded.
   8
   9 See: https://github.com/raspberrypi/linux/pull/4281
  10
  11 Suggested-by: Joe Burmeister <joe.burmeister@devtank.co.uk>
  12 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  13 ---
  14  drivers/spi/spi-bcm2835.c | 6 ++++++
  15  1 file changed, 6 insertions(+)
  16
  17 --- a/drivers/spi/spi-bcm2835.c
  18 +++ b/drivers/spi/spi-bcm2835.c
  19 @@ -28,6 +28,7 @@
  20  #include <linux/gpio/consumer.h>
  21  #include <linux/gpio/machine.h> /* FIXME: using chip internals */
  22  #include <linux/gpio/driver.h> /* FIXME: using chip internals */
  23 +#include <linux/of_gpio.h>
  24  #include <linux/of_irq.h>
  25  #include <linux/spi/spi.h>
  26
  27 @@ -1299,6 +1300,11 @@ static int bcm2835_spi_probe(struct plat
  28         struct bcm2835_spi *bs;
  29         int err;
  30
  31 +       if (of_gpio_named_count(pdev->dev.of_node, "cs-gpios") >
  32 +           BCM2835_SPI_NUM_CS)
  33 +               return dev_err_probe(&pdev->dev, -EINVAL,
  34 +                                    "too many chip selects\n");
  35 +
  36         ctlr = devm_spi_alloc_master(&pdev->dev, ALIGN(sizeof(*bs),
  37                                                   dma_get_cache_alignment()));
  38         if (!ctlr)