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git.ipfire.org Git - people/ms/u-boot.git/blob - drivers/spi/mpc8xxx_spi.c
2 * Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
3 * With help from the common/soft_spi and arch/powerpc/cpu/mpc8260 drivers
5 * See file CREDITS for list of people who contributed to this
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
28 #include <asm/mpc8xxx_spi.h>
30 #define SPI_EV_NE (0x80000000 >> 22) /* Receiver Not Empty */
31 #define SPI_EV_NF (0x80000000 >> 23) /* Transmitter Not Full */
33 #define SPI_MODE_LOOP (0x80000000 >> 1) /* Loopback mode */
34 #define SPI_MODE_REV (0x80000000 >> 5) /* Reverse mode - MSB first */
35 #define SPI_MODE_MS (0x80000000 >> 6) /* Always master */
36 #define SPI_MODE_EN (0x80000000 >> 7) /* Enable interface */
38 #define SPI_TIMEOUT 1000
40 struct spi_slave
*spi_setup_slave(unsigned int bus
, unsigned int cs
,
41 unsigned int max_hz
, unsigned int mode
)
43 struct spi_slave
*slave
;
45 if (!spi_cs_is_valid(bus
, cs
))
48 slave
= malloc(sizeof(struct spi_slave
));
56 * TODO: Some of the code in spi_init() should probably move
57 * here, or into spi_claim_bus() below.
63 void spi_free_slave(struct spi_slave
*slave
)
70 volatile spi8xxx_t
*spi
= &((immap_t
*) (CONFIG_SYS_IMMR
))->spi
;
73 * SPI pins on the MPC83xx are not muxed, so all we do is initialize
76 spi
->mode
= SPI_MODE_REV
| SPI_MODE_MS
| SPI_MODE_EN
;
77 spi
->mode
= (spi
->mode
& 0xfff0ffff) | (1 << 16); /* Use SYSCLK / 8
79 spi
->event
= 0xffffffff; /* Clear all SPI events */
80 spi
->mask
= 0x00000000; /* Mask all SPI interrupts */
81 spi
->com
= 0; /* LST bit doesn't do anything, so disregard */
84 int spi_claim_bus(struct spi_slave
*slave
)
89 void spi_release_bus(struct spi_slave
*slave
)
94 int spi_xfer(struct spi_slave
*slave
, unsigned int bitlen
, const void *dout
,
95 void *din
, unsigned long flags
)
97 volatile spi8xxx_t
*spi
= &((immap_t
*) (CONFIG_SYS_IMMR
))->spi
;
98 unsigned int tmpdout
, tmpdin
, event
;
99 int numBlks
= bitlen
/ 32 + (bitlen
% 32 ? 1 : 0);
101 unsigned char charSize
= 32;
103 debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
104 slave
->bus
, slave
->cs
, *(uint
*) dout
, *(uint
*) din
, bitlen
);
106 if (flags
& SPI_XFER_BEGIN
)
107 spi_cs_activate(slave
);
109 spi
->event
= 0xffffffff; /* Clear all SPI events */
111 /* handle data in 32-bit chunks */
114 charSize
= (bitlen
>= 32 ? 32 : bitlen
);
116 /* Shift data so it's msb-justified */
117 tmpdout
= *(u32
*) dout
>> (32 - charSize
);
119 /* The LEN field of the SPMODE register is set as follows:
123 * 4 < len <= 16 len - 1
129 spi
->mode
= (spi
->mode
& 0xff0fffff) |
132 spi
->mode
= (spi
->mode
& 0xff0fffff) |
133 ((bitlen
- 1) << 20);
135 spi
->mode
= (spi
->mode
& 0xff0fffff);
136 /* Set up the next iteration if sending > 32 bits */
141 spi
->tx
= tmpdout
; /* Write the data out */
142 debug("*** spi_xfer: ... %08x written\n", tmpdout
);
145 * Wait for SPI transmit to get out
146 * or time out (1 second = 1000 ms)
147 * The NE event must be read and cleared first
149 for (tm
= 0, isRead
= 0; tm
< SPI_TIMEOUT
; ++tm
) {
151 if (event
& SPI_EV_NE
) {
153 spi
->event
|= SPI_EV_NE
;
156 *(u32
*) din
= (tmpdin
<< (32 - charSize
));
157 if (charSize
== 32) {
158 /* Advance output buffer by 32 bits */
163 * Only bail when we've had both NE and NF events.
164 * This will cause timeouts on RO devices, so maybe
165 * in the future put an arbitrary delay after writing
166 * the device. Arbitrary delays suck, though...
168 if (isRead
&& (event
& SPI_EV_NF
))
171 if (tm
>= SPI_TIMEOUT
)
172 puts("*** spi_xfer: Time out during SPI transfer");
174 debug("*** spi_xfer: transfer ended. Value=%08x\n", tmpdin
);
177 if (flags
& SPI_XFER_END
)
178 spi_cs_deactivate(slave
);