62145a2f07d500db43da2c03b7020db12f2003f4
[openwrt/openwrt.git] / target / linux / brcm2708 / patches-4.9 / 950-0015-spi-bcm2835-Support-pin-groups-other-than-7-11.patch
1 From 6603973d0897c1a9b3b1a813c8ab1204efe98fe0 Mon Sep 17 00:00:00 2001
2 From: Phil Elwell <phil@raspberrypi.org>
3 Date: Wed, 24 Jun 2015 14:10:44 +0100
4 Subject: [PATCH] spi-bcm2835: Support pin groups other than 7-11
5
6 The spi-bcm2835 driver automatically uses GPIO chip-selects due to
7 some unreliability of the native ones. In doing so it chooses the
8 same pins as the native chip-selects would use, but the existing
9 code always uses pins 7 and 8, wherever the SPI function is mapped.
10
11 Search the pinctrl group assigned to the driver for pins that
12 correspond to native chip-selects, and use those for GPIO chip-
13 selects.
14
15 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
16 ---
17 drivers/spi/spi-bcm2835.c | 45 +++++++++++++++++++++++++++++++++++++--------
18 1 file changed, 37 insertions(+), 8 deletions(-)
19
20 --- a/drivers/spi/spi-bcm2835.c
21 +++ b/drivers/spi/spi-bcm2835.c
22 @@ -688,6 +688,8 @@ static int bcm2835_spi_setup(struct spi_
23 {
24 int err;
25 struct gpio_chip *chip;
26 + struct device_node *pins;
27 + u32 pingroup_index;
28 /*
29 * sanity checking the native-chipselects
30 */
31 @@ -704,15 +706,42 @@ static int bcm2835_spi_setup(struct spi_
32 "setup: only two native chip-selects are supported\n");
33 return -EINVAL;
34 }
35 - /* now translate native cs to GPIO */
36
37 - /* get the gpio chip for the base */
38 - chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
39 - if (!chip)
40 - return 0;
41 + /* now translate native cs to GPIO */
42 + /* first look for chip select pins in the devices pin groups */
43 + for (pingroup_index = 0;
44 + (pins = of_parse_phandle(spi->master->dev.of_node,
45 + "pinctrl-0",
46 + pingroup_index)) != 0;
47 + pingroup_index++) {
48 + u32 pin;
49 + u32 pin_index;
50 + for (pin_index = 0;
51 + of_property_read_u32_index(pins,
52 + "brcm,pins",
53 + pin_index,
54 + &pin) == 0;
55 + pin_index++) {
56 + if (((spi->chip_select == 0) &&
57 + ((pin == 8) || (pin == 36) || (pin == 46))) ||
58 + ((spi->chip_select == 1) &&
59 + ((pin == 7) || (pin == 35)))) {
60 + spi->cs_gpio = pin;
61 + break;
62 + }
63 + }
64 + of_node_put(pins);
65 + }
66 + /* if that fails, assume GPIOs 7-11 are used */
67 + if (!gpio_is_valid(spi->cs_gpio) ) {
68 + /* get the gpio chip for the base */
69 + chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
70 + if (!chip)
71 + return 0;
72
73 - /* and calculate the real CS */
74 - spi->cs_gpio = chip->base + 8 - spi->chip_select;
75 + /* and calculate the real CS */
76 + spi->cs_gpio = chip->base + 8 - spi->chip_select;
77 + }
78
79 /* and set up the "mode" and level */
80 dev_info(&spi->dev, "setting up native-CS%i as GPIO %i\n",