diff options
author | Michal Marek <mmarek@suse.cz> | 2010-10-27 18:15:57 -0400 |
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committer | Michal Marek <mmarek@suse.cz> | 2010-10-27 18:15:57 -0400 |
commit | b74b953b998bcc2db91b694446f3a2619ec32de6 (patch) | |
tree | 6ce24caabd730f6ae9287ed0676ec32e6ff31e9d /Documentation/spi/ep93xx_spi | |
parent | abb438526201c6a79949ad45375c051b6681c253 (diff) | |
parent | f6f94e2ab1b33f0082ac22d71f66385a60d8157f (diff) |
Merge commit 'v2.6.36' into kbuild/misc
Update to be able to fix a recent change to scripts/basic/docproc.c
(commit eda603f).
Diffstat (limited to 'Documentation/spi/ep93xx_spi')
-rw-r--r-- | Documentation/spi/ep93xx_spi | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/Documentation/spi/ep93xx_spi b/Documentation/spi/ep93xx_spi new file mode 100644 index 000000000000..6325f5b48635 --- /dev/null +++ b/Documentation/spi/ep93xx_spi | |||
@@ -0,0 +1,95 @@ | |||
1 | Cirrus EP93xx SPI controller driver HOWTO | ||
2 | ========================================= | ||
3 | |||
4 | ep93xx_spi driver brings SPI master support for EP93xx SPI controller. Chip | ||
5 | selects are implemented with GPIO lines. | ||
6 | |||
7 | NOTE: If possible, don't use SFRMOUT (SFRM1) signal as a chip select. It will | ||
8 | not work correctly (it cannot be controlled by software). Use GPIO lines | ||
9 | instead. | ||
10 | |||
11 | Sample configuration | ||
12 | ==================== | ||
13 | |||
14 | Typically driver configuration is done in platform board files (the files under | ||
15 | arch/arm/mach-ep93xx/*.c). In this example we configure MMC over SPI through | ||
16 | this driver on TS-7260 board. You can adapt the code to suit your needs. | ||
17 | |||
18 | This example uses EGPIO9 as SD/MMC card chip select (this is wired in DIO1 | ||
19 | header on the board). | ||
20 | |||
21 | You need to select CONFIG_MMC_SPI to use mmc_spi driver. | ||
22 | |||
23 | arch/arm/mach-ep93xx/ts72xx.c: | ||
24 | |||
25 | ... | ||
26 | #include <linux/gpio.h> | ||
27 | #include <linux/spi/spi.h> | ||
28 | |||
29 | #include <mach/ep93xx_spi.h> | ||
30 | |||
31 | /* this is our GPIO line used for chip select */ | ||
32 | #define MMC_CHIP_SELECT_GPIO EP93XX_GPIO_LINE_EGPIO9 | ||
33 | |||
34 | static int ts72xx_mmc_spi_setup(struct spi_device *spi) | ||
35 | { | ||
36 | int err; | ||
37 | |||
38 | err = gpio_request(MMC_CHIP_SELECT_GPIO, spi->modalias); | ||
39 | if (err) | ||
40 | return err; | ||
41 | |||
42 | gpio_direction_output(MMC_CHIP_SELECT_GPIO, 1); | ||
43 | |||
44 | return 0; | ||
45 | } | ||
46 | |||
47 | static void ts72xx_mmc_spi_cleanup(struct spi_device *spi) | ||
48 | { | ||
49 | gpio_set_value(MMC_CHIP_SELECT_GPIO, 1); | ||
50 | gpio_direction_input(MMC_CHIP_SELECT_GPIO); | ||
51 | gpio_free(MMC_CHIP_SELECT_GPIO); | ||
52 | } | ||
53 | |||
54 | static void ts72xx_mmc_spi_cs_control(struct spi_device *spi, int value) | ||
55 | { | ||
56 | gpio_set_value(MMC_CHIP_SELECT_GPIO, value); | ||
57 | } | ||
58 | |||
59 | static struct ep93xx_spi_chip_ops ts72xx_mmc_spi_ops = { | ||
60 | .setup = ts72xx_mmc_spi_setup, | ||
61 | .cleanup = ts72xx_mmc_spi_cleanup, | ||
62 | .cs_control = ts72xx_mmc_spi_cs_control, | ||
63 | }; | ||
64 | |||
65 | static struct spi_board_info ts72xx_spi_devices[] __initdata = { | ||
66 | { | ||
67 | .modalias = "mmc_spi", | ||
68 | .controller_data = &ts72xx_mmc_spi_ops, | ||
69 | /* | ||
70 | * We use 10 MHz even though the maximum is 7.4 MHz. The driver | ||
71 | * will limit it automatically to max. frequency. | ||
72 | */ | ||
73 | .max_speed_hz = 10 * 1000 * 1000, | ||
74 | .bus_num = 0, | ||
75 | .chip_select = 0, | ||
76 | .mode = SPI_MODE_0, | ||
77 | }, | ||
78 | }; | ||
79 | |||
80 | static struct ep93xx_spi_info ts72xx_spi_info = { | ||
81 | .num_chipselect = ARRAY_SIZE(ts72xx_spi_devices), | ||
82 | }; | ||
83 | |||
84 | static void __init ts72xx_init_machine(void) | ||
85 | { | ||
86 | ... | ||
87 | ep93xx_register_spi(&ts72xx_spi_info, ts72xx_spi_devices, | ||
88 | ARRAY_SIZE(ts72xx_spi_devices)); | ||
89 | } | ||
90 | |||
91 | Thanks to | ||
92 | ========= | ||
93 | Martin Guy, H. Hartley Sweeten and others who helped me during development of | ||
94 | the driver. Simplemachines.it donated me a Sim.One board which I used testing | ||
95 | the driver on EP9307. | ||