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- From f58037ac49ec4233848397cf67f84afa97a3ab38 Mon Sep 17 00:00:00 2001
- From: Phil Elwell <phil@raspberrypi.org>
- Date: Wed, 24 Jun 2015 14:10:44 +0100
- Subject: [PATCH] spi-bcm2835: Support pin groups other than 7-11
- The spi-bcm2835 driver automatically uses GPIO chip-selects due to
- some unreliability of the native ones. In doing so it chooses the
- same pins as the native chip-selects would use, but the existing
- code always uses pins 7 and 8, wherever the SPI function is mapped.
- Search the pinctrl group assigned to the driver for pins that
- correspond to native chip-selects, and use those for GPIO chip-
- selects.
- Signed-off-by: Phil Elwell <phil@raspberrypi.org>
- ---
- drivers/spi/spi-bcm2835.c | 45 +++++++++++++++++++++++++++++++++++++--------
- 1 file changed, 37 insertions(+), 8 deletions(-)
- --- a/drivers/spi/spi-bcm2835.c
- +++ b/drivers/spi/spi-bcm2835.c
- @@ -687,6 +687,8 @@ static int bcm2835_spi_setup(struct spi_
- {
- int err;
- struct gpio_chip *chip;
- + struct device_node *pins;
- + u32 pingroup_index;
- /*
- * sanity checking the native-chipselects
- */
- @@ -703,15 +705,42 @@ static int bcm2835_spi_setup(struct spi_
- "setup: only two native chip-selects are supported\n");
- return -EINVAL;
- }
- - /* now translate native cs to GPIO */
-
- - /* get the gpio chip for the base */
- - chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
- - if (!chip)
- - return 0;
- + /* now translate native cs to GPIO */
- + /* first look for chip select pins in the devices pin groups */
- + for (pingroup_index = 0;
- + (pins = of_parse_phandle(spi->master->dev.of_node,
- + "pinctrl-0",
- + pingroup_index)) != 0;
- + pingroup_index++) {
- + u32 pin;
- + u32 pin_index;
- + for (pin_index = 0;
- + of_property_read_u32_index(pins,
- + "brcm,pins",
- + pin_index,
- + &pin) == 0;
- + pin_index++) {
- + if (((spi->chip_select == 0) &&
- + ((pin == 8) || (pin == 36) || (pin == 46))) ||
- + ((spi->chip_select == 1) &&
- + ((pin == 7) || (pin == 35)))) {
- + spi->cs_gpio = pin;
- + break;
- + }
- + }
- + of_node_put(pins);
- + }
- + /* if that fails, assume GPIOs 7-11 are used */
- + if (!gpio_is_valid(spi->cs_gpio) ) {
- + /* get the gpio chip for the base */
- + chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
- + if (!chip)
- + return 0;
-
- - /* and calculate the real CS */
- - spi->cs_gpio = chip->base + 8 - spi->chip_select;
- + /* and calculate the real CS */
- + spi->cs_gpio = chip->base + 8 - spi->chip_select;
- + }
-
- /* and set up the "mode" and level */
- dev_info(&spi->dev, "setting up native-CS%i as GPIO %i\n",
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