1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
/*
* Freescale i.MX28 SPI driver
*
* Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
* on behalf of DENX Software Engineering GmbH
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
* NOTE: This driver only supports the SPI-controller chipselects,
* GPIO driven chipselects are not supported.
*/
#include <common.h>
#include <malloc.h>
#include <spi.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/arch/sys_proto.h>
#define MXS_SPI_MAX_TIMEOUT 1000000
#define MXS_SPI_PORT_OFFSET 0x2000
struct mxs_spi_slave {
struct spi_slave slave;
uint32_t max_khz;
uint32_t mode;
struct mx28_ssp_regs *regs;
};
static inline struct mxs_spi_slave *to_mxs_slave(struct spi_slave *slave)
{
return container_of(slave, struct mxs_spi_slave, slave);
}
void spi_init(void)
{
}
int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
/* MXS SPI: 4 ports and 3 chip selects maximum */
if (bus > 3 || cs > 2)
return 0;
else
return 1;
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct mxs_spi_slave *mxs_slave;
uint32_t addr;
if (!spi_cs_is_valid(bus, cs)) {
printf("mxs_spi: invalid bus %d / chip select %d\n", bus, cs);
return NULL;
}
mxs_slave = malloc(sizeof(struct mxs_spi_slave));
if (!mxs_slave)
return NULL;
addr = MXS_SSP0_BASE + (bus * MXS_SPI_PORT_OFFSET);
mxs_slave->slave.bus = bus;
mxs_slave->slave.cs = cs;
mxs_slave->max_khz = max_hz / 1000;
mxs_slave->mode = mode;
mxs_slave->regs = (struct mx28_ssp_regs *)addr;
return &mxs_slave->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
free(mxs_slave);
}
int spi_claim_bus(struct spi_slave *slave)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
struct mx28_ssp_regs *ssp_regs = mxs_slave->regs;
uint32_t reg = 0;
mx28_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
writel(SSP_CTRL0_BUS_WIDTH_ONE_BIT, &ssp_regs->hw_ssp_ctrl0);
reg = SSP_CTRL1_SSP_MODE_SPI | SSP_CTRL1_WORD_LENGTH_EIGHT_BITS;
reg |= (mxs_slave->mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0;
reg |= (mxs_slave->mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0;
writel(reg, &ssp_regs->hw_ssp_ctrl1);
writel(0, &ssp_regs->hw_ssp_cmd0);
mx28_set_ssp_busclock(slave->bus, mxs_slave->max_khz);
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
}
static void mxs_spi_start_xfer(struct mx28_ssp_regs *ssp_regs)
{
writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_set);
writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_clr);
}
static void mxs_spi_end_xfer(struct mx28_ssp_regs *ssp_regs)
{
writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_clr);
writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set);
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
struct mx28_ssp_regs *ssp_regs = mxs_slave->regs;
int len = bitlen / 8;
const char *tx = dout;
char *rx = din;
char dummy;
if (bitlen == 0) {
if (flags & SPI_XFER_END) {
rx = &dummy;
len = 1;
} else
return 0;
}
if (!rx && !tx)
return 0;
if (flags & SPI_XFER_BEGIN)
mxs_spi_start_xfer(ssp_regs);
while (len--) {
/* We transfer 1 byte */
writel(1, &ssp_regs->hw_ssp_xfer_size);
if ((flags & SPI_XFER_END) && !len)
mxs_spi_end_xfer(ssp_regs);
if (tx)
writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_clr);
else
writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_set);
writel(SSP_CTRL0_RUN, &ssp_regs->hw_ssp_ctrl0_set);
if (mx28_wait_mask_set(&ssp_regs->hw_ssp_ctrl0_reg,
SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
printf("MXS SPI: Timeout waiting for start\n");
return -ETIMEDOUT;
}
if (tx)
writel(*tx++, &ssp_regs->hw_ssp_data);
writel(SSP_CTRL0_DATA_XFER, &ssp_regs->hw_ssp_ctrl0_set);
if (rx) {
if (mx28_wait_mask_clr(&ssp_regs->hw_ssp_status_reg,
SSP_STATUS_FIFO_EMPTY, MXS_SPI_MAX_TIMEOUT)) {
printf("MXS SPI: Timeout waiting for data\n");
return -ETIMEDOUT;
}
*rx = readl(&ssp_regs->hw_ssp_data);
rx++;
}
if (mx28_wait_mask_clr(&ssp_regs->hw_ssp_ctrl0_reg,
SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
printf("MXS SPI: Timeout waiting for finish\n");
return -ETIMEDOUT;
}
}
return 0;
}
|
