2 * SPI controller driver for the Mikrotik RB4xx boards
4 * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
6 * This file was based on the patches for Linux 2.6.27.39 published by
7 * MikroTik for their RouterBoard 4xx series devices.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
15 #include <linux/clk.h>
16 #include <linux/err.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/delay.h>
21 #include <linux/spinlock.h>
22 #include <linux/workqueue.h>
23 #include <linux/platform_device.h>
24 #include <linux/spi/spi.h>
26 #include <asm/mach-ath79/ar71xx_regs.h>
27 #include <asm/mach-ath79/ath79.h>
29 #define DRV_NAME "rb4xx-spi"
30 #define DRV_DESC "Mikrotik RB4xx SPI controller driver"
31 #define DRV_VERSION "0.1.0"
33 #define SPI_CTRL_FASTEST 0x40
34 #define SPI_FLASH_HZ 33333334
35 #define SPI_CPLD_HZ 33333334
37 #define CPLD_CMD_READ_FAST 0x0b
39 #undef RB4XX_SPI_DEBUG
43 struct spi_master
*master
;
45 unsigned spi_ctrl_flash
;
46 unsigned spi_ctrl_fread
;
49 unsigned long ahb_freq
;
52 struct list_head queue
;
57 static unsigned spi_clk_low
= AR71XX_SPI_IOC_CS1
;
59 #ifdef RB4XX_SPI_DEBUG
60 static inline void do_spi_delay(void)
65 static inline void do_spi_delay(void) { }
68 static inline void do_spi_init(struct spi_device
*spi
)
70 unsigned cs
= AR71XX_SPI_IOC_CS0
| AR71XX_SPI_IOC_CS1
;
72 if (!(spi
->mode
& SPI_CS_HIGH
))
73 cs
^= (spi
->chip_select
== 2) ? AR71XX_SPI_IOC_CS1
:
79 static inline void do_spi_finish(void __iomem
*base
)
82 __raw_writel(AR71XX_SPI_IOC_CS0
| AR71XX_SPI_IOC_CS1
,
83 base
+ AR71XX_SPI_REG_IOC
);
86 static inline void do_spi_clk(void __iomem
*base
, int bit
)
88 unsigned bval
= spi_clk_low
| ((bit
& 1) ? AR71XX_SPI_IOC_DO
: 0);
91 __raw_writel(bval
, base
+ AR71XX_SPI_REG_IOC
);
93 __raw_writel(bval
| AR71XX_SPI_IOC_CLK
, base
+ AR71XX_SPI_REG_IOC
);
96 static void do_spi_byte(void __iomem
*base
, unsigned char byte
)
98 do_spi_clk(base
, byte
>> 7);
99 do_spi_clk(base
, byte
>> 6);
100 do_spi_clk(base
, byte
>> 5);
101 do_spi_clk(base
, byte
>> 4);
102 do_spi_clk(base
, byte
>> 3);
103 do_spi_clk(base
, byte
>> 2);
104 do_spi_clk(base
, byte
>> 1);
105 do_spi_clk(base
, byte
);
107 pr_debug("spi_byte sent 0x%02x got 0x%02x\n",
109 (unsigned char)__raw_readl(base
+ AR71XX_SPI_REG_RDS
));
112 static inline void do_spi_clk_fast(void __iomem
*base
, unsigned bit1
,
115 unsigned bval
= (spi_clk_low
|
116 ((bit1
& 1) ? AR71XX_SPI_IOC_DO
: 0) |
117 ((bit2
& 1) ? AR71XX_SPI_IOC_CS2
: 0));
119 __raw_writel(bval
, base
+ AR71XX_SPI_REG_IOC
);
121 __raw_writel(bval
| AR71XX_SPI_IOC_CLK
, base
+ AR71XX_SPI_REG_IOC
);
124 static void do_spi_byte_fast(void __iomem
*base
, unsigned char byte
)
126 do_spi_clk_fast(base
, byte
>> 7, byte
>> 6);
127 do_spi_clk_fast(base
, byte
>> 5, byte
>> 4);
128 do_spi_clk_fast(base
, byte
>> 3, byte
>> 2);
129 do_spi_clk_fast(base
, byte
>> 1, byte
>> 0);
131 pr_debug("spi_byte_fast sent 0x%02x got 0x%02x\n",
133 (unsigned char) __raw_readl(base
+ AR71XX_SPI_REG_RDS
));
136 static int rb4xx_spi_txrx(void __iomem
*base
, struct spi_transfer
*t
)
138 const unsigned char *tx_ptr
= t
->tx_buf
;
139 unsigned char *rx_ptr
= t
->rx_buf
;
142 pr_debug("spi_txrx len %u tx %u rx %u\n",
145 (t
->rx_buf
? 1 : 0));
147 for (i
= 0; i
< t
->len
; ++i
) {
148 unsigned char sdata
= tx_ptr
? tx_ptr
[i
] : 0;
150 if (t
->tx_nbits
== SPI_NBITS_DUAL
)
151 do_spi_byte_fast(base
, sdata
);
153 do_spi_byte(base
, sdata
);
156 rx_ptr
[i
] = __raw_readl(base
+ AR71XX_SPI_REG_RDS
) & 0xff;
162 static int rb4xx_spi_msg(struct rb4xx_spi
*rbspi
, struct spi_message
*m
)
164 struct spi_transfer
*t
= NULL
;
165 void __iomem
*base
= rbspi
->base
;
168 if (list_empty(&m
->transfers
))
171 __raw_writel(AR71XX_SPI_FS_GPIO
, base
+ AR71XX_SPI_REG_FS
);
172 __raw_writel(SPI_CTRL_FASTEST
, base
+ AR71XX_SPI_REG_CTRL
);
175 list_for_each_entry(t
, &m
->transfers
, transfer_list
) {
178 len
= rb4xx_spi_txrx(base
, t
);
180 m
->status
= -EMSGSIZE
;
183 m
->actual_length
+= len
;
186 if (list_is_last(&t
->transfer_list
, &m
->transfers
)) {
187 /* wait for continuation */
188 return m
->spi
->chip_select
;
196 __raw_writel(rbspi
->spi_ctrl_flash
, base
+ AR71XX_SPI_REG_CTRL
);
197 __raw_writel(0, base
+ AR71XX_SPI_REG_FS
);
201 static void rb4xx_spi_process_queue_locked(struct rb4xx_spi
*rbspi
,
202 unsigned long *flags
)
204 int cs
= rbspi
->cs_wait
;
207 while (!list_empty(&rbspi
->queue
)) {
208 struct spi_message
*m
;
210 list_for_each_entry(m
, &rbspi
->queue
, queue
)
211 if (cs
< 0 || cs
== m
->spi
->chip_select
)
214 if (&m
->queue
== &rbspi
->queue
)
217 list_del_init(&m
->queue
);
218 spin_unlock_irqrestore(&rbspi
->lock
, *flags
);
220 cs
= rb4xx_spi_msg(rbspi
, m
);
221 m
->complete(m
->context
);
223 spin_lock_irqsave(&rbspi
->lock
, *flags
);
230 /* TODO: add timer to unlock cs after 1s inactivity */
234 static int rb4xx_spi_transfer(struct spi_device
*spi
,
235 struct spi_message
*m
)
237 struct rb4xx_spi
*rbspi
= spi_master_get_devdata(spi
->master
);
240 m
->actual_length
= 0;
241 m
->status
= -EINPROGRESS
;
243 spin_lock_irqsave(&rbspi
->lock
, flags
);
244 list_add_tail(&m
->queue
, &rbspi
->queue
);
246 (rbspi
->cs_wait
>= 0 && rbspi
->cs_wait
!= m
->spi
->chip_select
)) {
247 /* job will be done later */
248 spin_unlock_irqrestore(&rbspi
->lock
, flags
);
252 /* process job in current context */
253 rb4xx_spi_process_queue_locked(rbspi
, &flags
);
254 spin_unlock_irqrestore(&rbspi
->lock
, flags
);
259 static int rb4xx_spi_setup(struct spi_device
*spi
)
261 struct rb4xx_spi
*rbspi
= spi_master_get_devdata(spi
->master
);
264 if (spi
->mode
& ~(SPI_CS_HIGH
)) {
265 dev_err(&spi
->dev
, "mode %x not supported\n",
266 (unsigned) spi
->mode
);
270 if (spi
->bits_per_word
!= 8 && spi
->bits_per_word
!= 0) {
271 dev_err(&spi
->dev
, "bits_per_word %u not supported\n",
272 (unsigned) spi
->bits_per_word
);
276 spin_lock_irqsave(&rbspi
->lock
, flags
);
277 if (rbspi
->cs_wait
== spi
->chip_select
&& !rbspi
->busy
) {
279 rb4xx_spi_process_queue_locked(rbspi
, &flags
);
281 spin_unlock_irqrestore(&rbspi
->lock
, flags
);
286 static unsigned get_spi_ctrl(struct rb4xx_spi
*rbspi
, unsigned hz_max
,
291 div
= (rbspi
->ahb_freq
- 1) / (2 * hz_max
);
294 * CPU has a bug at (div == 0) - first bit read is random
300 unsigned ahb_khz
= (rbspi
->ahb_freq
+ 500) / 1000;
301 unsigned div_real
= 2 * (div
+ 1);
302 pr_debug("rb4xx: %s SPI clock %u kHz (AHB %u kHz / %u)\n",
308 return SPI_CTRL_FASTEST
+ div
;
311 static int rb4xx_spi_probe(struct platform_device
*pdev
)
313 struct spi_master
*master
;
314 struct rb4xx_spi
*rbspi
;
318 master
= spi_alloc_master(&pdev
->dev
, sizeof(*rbspi
));
319 if (master
== NULL
) {
320 dev_err(&pdev
->dev
, "no memory for spi_master\n");
326 master
->num_chipselect
= 3;
327 master
->mode_bits
= SPI_TX_DUAL
;
328 master
->setup
= rb4xx_spi_setup
;
329 master
->transfer
= rb4xx_spi_transfer
;
331 rbspi
= spi_master_get_devdata(master
);
333 rbspi
->ahb_clk
= clk_get(&pdev
->dev
, "ahb");
334 if (IS_ERR(rbspi
->ahb_clk
)) {
335 err
= PTR_ERR(rbspi
->ahb_clk
);
339 err
= clk_prepare_enable(rbspi
->ahb_clk
);
343 rbspi
->ahb_freq
= clk_get_rate(rbspi
->ahb_clk
);
344 if (!rbspi
->ahb_freq
) {
346 goto err_clk_disable
;
349 platform_set_drvdata(pdev
, rbspi
);
351 r
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
354 goto err_clk_disable
;
357 rbspi
->base
= ioremap(r
->start
, r
->end
- r
->start
+ 1);
360 goto err_clk_disable
;
363 rbspi
->master
= master
;
364 rbspi
->spi_ctrl_flash
= get_spi_ctrl(rbspi
, SPI_FLASH_HZ
, "FLASH");
365 rbspi
->spi_ctrl_fread
= get_spi_ctrl(rbspi
, SPI_CPLD_HZ
, "CPLD");
368 spin_lock_init(&rbspi
->lock
);
369 INIT_LIST_HEAD(&rbspi
->queue
);
371 err
= spi_register_master(master
);
373 dev_err(&pdev
->dev
, "failed to register SPI master\n");
380 iounmap(rbspi
->base
);
382 clk_disable(rbspi
->ahb_clk
);
384 clk_put(rbspi
->ahb_clk
);
386 platform_set_drvdata(pdev
, NULL
);
387 spi_master_put(master
);
392 static int rb4xx_spi_remove(struct platform_device
*pdev
)
394 struct rb4xx_spi
*rbspi
= platform_get_drvdata(pdev
);
396 iounmap(rbspi
->base
);
397 clk_disable(rbspi
->ahb_clk
);
398 clk_put(rbspi
->ahb_clk
);
399 platform_set_drvdata(pdev
, NULL
);
400 spi_master_put(rbspi
->master
);
405 static struct platform_driver rb4xx_spi_drv
= {
406 .probe
= rb4xx_spi_probe
,
407 .remove
= rb4xx_spi_remove
,
410 .owner
= THIS_MODULE
,
414 static int __init
rb4xx_spi_init(void)
416 return platform_driver_register(&rb4xx_spi_drv
);
418 subsys_initcall(rb4xx_spi_init
);
420 static void __exit
rb4xx_spi_exit(void)
422 platform_driver_unregister(&rb4xx_spi_drv
);
425 module_exit(rb4xx_spi_exit
);
427 MODULE_DESCRIPTION(DRV_DESC
);
428 MODULE_VERSION(DRV_VERSION
);
429 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
430 MODULE_LICENSE("GPL v2");