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-rw-r--r--arch/arm/mach-u300/spi.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/arm/mach-u300/spi.c b/arch/arm/mach-u300/spi.c
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1/*
2 * arch/arm/mach-u300/spi.c
3 *
4 * Copyright (C) 2009 ST-Ericsson AB
5 * License terms: GNU General Public License (GPL) version 2
6 *
7 * Author: Linus Walleij <linus.walleij@stericsson.com>
8 */
9#include <linux/device.h>
10#include <linux/amba/bus.h>
11#include <linux/spi/spi.h>
12#include <linux/amba/pl022.h>
13#include <linux/err.h>
14#include "padmux.h"
15
16/*
17 * The following is for the actual devices on the SSP/SPI bus
18 */
19#ifdef CONFIG_MACH_U300_SPIDUMMY
20static void select_dummy_chip(u32 chipselect)
21{
22 pr_debug("CORE: %s called with CS=0x%x (%s)\n",
23 __func__,
24 chipselect,
25 chipselect ? "unselect chip" : "select chip");
26 /*
27 * Here you would write the chip select value to the GPIO pins if
28 * this was a real chip (but this is a loopback dummy).
29 */
30}
31
32struct pl022_config_chip dummy_chip_info = {
33 /* Nominally this is LOOPBACK_DISABLED, but this is our dummy chip! */
34 .lbm = LOOPBACK_ENABLED,
35 /*
36 * available POLLING_TRANSFER and INTERRUPT_TRANSFER,
37 * DMA_TRANSFER does not work
38 */
39 .com_mode = INTERRUPT_TRANSFER,
40 .iface = SSP_INTERFACE_MOTOROLA_SPI,
41 /* We can only act as master but SSP_SLAVE is possible in theory */
42 .hierarchy = SSP_MASTER,
43 /* 0 = drive TX even as slave, 1 = do not drive TX as slave */
44 .slave_tx_disable = 0,
45 /* LSB first */
46 .endian_tx = SSP_TX_LSB,
47 .endian_rx = SSP_RX_LSB,
48 .data_size = SSP_DATA_BITS_8, /* used to be 12 in some default */
49 .rx_lev_trig = SSP_RX_1_OR_MORE_ELEM,
50 .tx_lev_trig = SSP_TX_1_OR_MORE_EMPTY_LOC,
51 .clk_phase = SSP_CLK_SECOND_EDGE,
52 .clk_pol = SSP_CLK_POL_IDLE_LOW,
53 .ctrl_len = SSP_BITS_12,
54 .wait_state = SSP_MWIRE_WAIT_ZERO,
55 .duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
56 /*
57 * This is where you insert a call to a function to enable CS
58 * (usually GPIO) for a certain chip.
59 */
60 .cs_control = select_dummy_chip,
61};
62#endif
63
64static struct spi_board_info u300_spi_devices[] = {
65#ifdef CONFIG_MACH_U300_SPIDUMMY
66 {
67 /* A dummy chip used for loopback tests */
68 .modalias = "spi-dummy",
69 /* Really dummy, pass in additional chip config here */
70 .platform_data = NULL,
71 /* This defines how the controller shall handle the device */
72 .controller_data = &dummy_chip_info,
73 /* .irq - no external IRQ routed from this device */
74 .max_speed_hz = 1000000,
75 .bus_num = 0, /* Only one bus on this chip */
76 .chip_select = 0,
77 /* Means SPI_CS_HIGH, change if e.g low CS */
78 .mode = 0,
79 },
80#endif
81};
82
83static struct pl022_ssp_controller ssp_platform_data = {
84 /* If you have several SPI buses this varies, we have only bus 0 */
85 .bus_id = 0,
86 /* Set this to 1 when we think we got DMA working */
87 .enable_dma = 0,
88 /*
89 * On the APP CPU GPIO 4, 5 and 6 are connected as generic
90 * chip selects for SPI. (Same on U330, U335 and U365.)
91 * TODO: make sure the GPIO driver can select these properly
92 * and do padmuxing accordingly too.
93 */
94 .num_chipselect = 3,
95};
96
97
98void __init u300_spi_init(struct amba_device *adev)
99{
100 struct pmx *pmx;
101
102 adev->dev.platform_data = &ssp_platform_data;
103 /*
104 * Setup padmuxing for SPI. Since this must always be
105 * compiled into the kernel, pmx is never released.
106 */
107 pmx = pmx_get(&adev->dev, U300_APP_PMX_SPI_SETTING);
108
109 if (IS_ERR(pmx))
110 dev_warn(&adev->dev, "Could not get padmux handle\n");
111 else {
112 int ret;
113
114 ret = pmx_activate(&adev->dev, pmx);
115 if (IS_ERR_VALUE(ret))
116 dev_warn(&adev->dev, "Could not activate padmuxing\n");
117 }
118
119}
120void __init u300_spi_register_board_devices(void)
121{
122 /* Register any SPI devices */
123 spi_register_board_info(u300_spi_devices, ARRAY_SIZE(u300_spi_devices));
124}