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1 | /* | |
2 | * SPI controller driver for the Atheros AR71XX/AR724X/AR913X SoCs | |
3 | * | |
4 | * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org> | |
5 | * | |
6 | * This driver has been based on the spi-gpio.c: | |
7 | * Copyright (C) 2006,2008 David Brownell | |
8 | * | |
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. | |
12 | * | |
13 | */ | |
14 | ||
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/delay.h> | |
18 | #include <linux/spinlock.h> | |
19 | #include <linux/workqueue.h> | |
20 | #include <linux/platform_device.h> | |
21 | #include <linux/io.h> | |
22 | #include <linux/spi/spi.h> | |
23 | #include <linux/spi/spi_bitbang.h> | |
24 | #include <linux/bitops.h> | |
25 | #include <linux/gpio.h> | |
26 | #include <linux/clk.h> | |
27 | #include <linux/err.h> | |
28 | ||
29 | #include <asm/mach-ath79/ar71xx_regs.h> | |
30 | #include <asm/mach-ath79/ath79_spi_platform.h> | |
31 | ||
32 | #define DRV_NAME "ath79-spi" | |
33 | ||
34 | #define ATH79_SPI_RRW_DELAY_FACTOR 12000 | |
35 | #define MHZ (1000 * 1000) | |
36 | ||
37 | struct ath79_spi { | |
38 | struct spi_bitbang bitbang; | |
39 | u32 ioc_base; | |
40 | u32 reg_ctrl; | |
41 | void __iomem *base; | |
42 | struct clk *clk; | |
43 | unsigned rrw_delay; | |
44 | }; | |
45 | ||
46 | static inline u32 ath79_spi_rr(struct ath79_spi *sp, unsigned reg) | |
47 | { | |
48 | return ioread32(sp->base + reg); | |
49 | } | |
50 | ||
51 | static inline void ath79_spi_wr(struct ath79_spi *sp, unsigned reg, u32 val) | |
52 | { | |
53 | iowrite32(val, sp->base + reg); | |
54 | } | |
55 | ||
56 | static inline struct ath79_spi *ath79_spidev_to_sp(struct spi_device *spi) | |
57 | { | |
58 | return spi_master_get_devdata(spi->master); | |
59 | } | |
60 | ||
61 | static inline void ath79_spi_delay(struct ath79_spi *sp, unsigned nsecs) | |
62 | { | |
63 | if (nsecs > sp->rrw_delay) | |
64 | ndelay(nsecs - sp->rrw_delay); | |
65 | } | |
66 | ||
67 | static void ath79_spi_chipselect(struct spi_device *spi, int is_active) | |
68 | { | |
69 | struct ath79_spi *sp = ath79_spidev_to_sp(spi); | |
70 | int cs_high = (spi->mode & SPI_CS_HIGH) ? is_active : !is_active; | |
71 | ||
72 | if (is_active) { | |
73 | /* set initial clock polarity */ | |
74 | if (spi->mode & SPI_CPOL) | |
75 | sp->ioc_base |= AR71XX_SPI_IOC_CLK; | |
76 | else | |
77 | sp->ioc_base &= ~AR71XX_SPI_IOC_CLK; | |
78 | ||
79 | ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base); | |
80 | } | |
81 | ||
82 | if (spi->chip_select) { | |
83 | struct ath79_spi_controller_data *cdata = spi->controller_data; | |
84 | ||
85 | /* SPI is normally active-low */ | |
86 | gpio_set_value(cdata->gpio, cs_high); | |
87 | } else { | |
88 | if (cs_high) | |
89 | sp->ioc_base |= AR71XX_SPI_IOC_CS0; | |
90 | else | |
91 | sp->ioc_base &= ~AR71XX_SPI_IOC_CS0; | |
92 | ||
93 | ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base); | |
94 | } | |
95 | ||
96 | } | |
97 | ||
98 | static void ath79_spi_enable(struct ath79_spi *sp) | |
99 | { | |
100 | /* enable GPIO mode */ | |
101 | ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO); | |
102 | ||
103 | /* save CTRL register */ | |
104 | sp->reg_ctrl = ath79_spi_rr(sp, AR71XX_SPI_REG_CTRL); | |
105 | sp->ioc_base = ath79_spi_rr(sp, AR71XX_SPI_REG_IOC); | |
106 | ||
107 | /* TODO: setup speed? */ | |
108 | ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43); | |
109 | } | |
110 | ||
111 | static void ath79_spi_disable(struct ath79_spi *sp) | |
112 | { | |
113 | /* restore CTRL register */ | |
114 | ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl); | |
115 | /* disable GPIO mode */ | |
116 | ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0); | |
117 | } | |
118 | ||
119 | static int ath79_spi_setup_cs(struct spi_device *spi) | |
120 | { | |
121 | struct ath79_spi_controller_data *cdata; | |
122 | int status; | |
123 | ||
124 | cdata = spi->controller_data; | |
125 | if (spi->chip_select && !cdata) | |
126 | return -EINVAL; | |
127 | ||
128 | status = 0; | |
129 | if (spi->chip_select) { | |
130 | unsigned long flags; | |
131 | ||
132 | flags = GPIOF_DIR_OUT; | |
133 | if (spi->mode & SPI_CS_HIGH) | |
134 | flags |= GPIOF_INIT_LOW; | |
135 | else | |
136 | flags |= GPIOF_INIT_HIGH; | |
137 | ||
138 | status = gpio_request_one(cdata->gpio, flags, | |
139 | dev_name(&spi->dev)); | |
140 | } | |
141 | ||
142 | return status; | |
143 | } | |
144 | ||
145 | static void ath79_spi_cleanup_cs(struct spi_device *spi) | |
146 | { | |
147 | if (spi->chip_select) { | |
148 | struct ath79_spi_controller_data *cdata = spi->controller_data; | |
149 | gpio_free(cdata->gpio); | |
150 | } | |
151 | } | |
152 | ||
153 | static int ath79_spi_setup(struct spi_device *spi) | |
154 | { | |
155 | int status = 0; | |
156 | ||
157 | if (!spi->controller_state) { | |
158 | status = ath79_spi_setup_cs(spi); | |
159 | if (status) | |
160 | return status; | |
161 | } | |
162 | ||
163 | status = spi_bitbang_setup(spi); | |
164 | if (status && !spi->controller_state) | |
165 | ath79_spi_cleanup_cs(spi); | |
166 | ||
167 | return status; | |
168 | } | |
169 | ||
170 | static void ath79_spi_cleanup(struct spi_device *spi) | |
171 | { | |
172 | ath79_spi_cleanup_cs(spi); | |
173 | spi_bitbang_cleanup(spi); | |
174 | } | |
175 | ||
176 | static u32 ath79_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs, | |
177 | u32 word, u8 bits) | |
178 | { | |
179 | struct ath79_spi *sp = ath79_spidev_to_sp(spi); | |
180 | u32 ioc = sp->ioc_base; | |
181 | ||
182 | /* clock starts at inactive polarity */ | |
183 | for (word <<= (32 - bits); likely(bits); bits--) { | |
184 | u32 out; | |
185 | ||
186 | if (word & (1 << 31)) | |
187 | out = ioc | AR71XX_SPI_IOC_DO; | |
188 | else | |
189 | out = ioc & ~AR71XX_SPI_IOC_DO; | |
190 | ||
191 | /* setup MSB (to slave) on trailing edge */ | |
192 | ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out); | |
193 | ath79_spi_delay(sp, nsecs); | |
194 | ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK); | |
195 | ath79_spi_delay(sp, nsecs); | |
196 | if (bits == 1) | |
197 | ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out); | |
198 | ||
199 | word <<= 1; | |
200 | } | |
201 | ||
202 | return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS); | |
203 | } | |
204 | ||
205 | static int ath79_spi_probe(struct platform_device *pdev) | |
206 | { | |
207 | struct spi_master *master; | |
208 | struct ath79_spi *sp; | |
209 | struct ath79_spi_platform_data *pdata; | |
210 | struct resource *r; | |
211 | unsigned long rate; | |
212 | int ret; | |
213 | ||
214 | master = spi_alloc_master(&pdev->dev, sizeof(*sp)); | |
215 | if (master == NULL) { | |
216 | dev_err(&pdev->dev, "failed to allocate spi master\n"); | |
217 | return -ENOMEM; | |
218 | } | |
219 | ||
220 | sp = spi_master_get_devdata(master); | |
221 | platform_set_drvdata(pdev, sp); | |
222 | ||
223 | pdata = dev_get_platdata(&pdev->dev); | |
224 | ||
225 | master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32); | |
226 | master->setup = ath79_spi_setup; | |
227 | master->cleanup = ath79_spi_cleanup; | |
228 | if (pdata) { | |
229 | master->bus_num = pdata->bus_num; | |
230 | master->num_chipselect = pdata->num_chipselect; | |
231 | } | |
232 | ||
233 | sp->bitbang.master = master; | |
234 | sp->bitbang.chipselect = ath79_spi_chipselect; | |
235 | sp->bitbang.txrx_word[SPI_MODE_0] = ath79_spi_txrx_mode0; | |
236 | sp->bitbang.setup_transfer = spi_bitbang_setup_transfer; | |
237 | sp->bitbang.flags = SPI_CS_HIGH; | |
238 | ||
239 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
240 | if (r == NULL) { | |
241 | ret = -ENOENT; | |
242 | goto err_put_master; | |
243 | } | |
244 | ||
245 | sp->base = devm_ioremap(&pdev->dev, r->start, resource_size(r)); | |
246 | if (!sp->base) { | |
247 | ret = -ENXIO; | |
248 | goto err_put_master; | |
249 | } | |
250 | ||
251 | sp->clk = devm_clk_get(&pdev->dev, "ahb"); | |
252 | if (IS_ERR(sp->clk)) { | |
253 | ret = PTR_ERR(sp->clk); | |
254 | goto err_put_master; | |
255 | } | |
256 | ||
257 | ret = clk_enable(sp->clk); | |
258 | if (ret) | |
259 | goto err_put_master; | |
260 | ||
261 | rate = DIV_ROUND_UP(clk_get_rate(sp->clk), MHZ); | |
262 | if (!rate) { | |
263 | ret = -EINVAL; | |
264 | goto err_clk_disable; | |
265 | } | |
266 | ||
267 | sp->rrw_delay = ATH79_SPI_RRW_DELAY_FACTOR / rate; | |
268 | dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n", | |
269 | sp->rrw_delay); | |
270 | ||
271 | ath79_spi_enable(sp); | |
272 | ret = spi_bitbang_start(&sp->bitbang); | |
273 | if (ret) | |
274 | goto err_disable; | |
275 | ||
276 | return 0; | |
277 | ||
278 | err_disable: | |
279 | ath79_spi_disable(sp); | |
280 | err_clk_disable: | |
281 | clk_disable(sp->clk); | |
282 | err_put_master: | |
283 | spi_master_put(sp->bitbang.master); | |
284 | ||
285 | return ret; | |
286 | } | |
287 | ||
288 | static int ath79_spi_remove(struct platform_device *pdev) | |
289 | { | |
290 | struct ath79_spi *sp = platform_get_drvdata(pdev); | |
291 | ||
292 | spi_bitbang_stop(&sp->bitbang); | |
293 | ath79_spi_disable(sp); | |
294 | clk_disable(sp->clk); | |
295 | spi_master_put(sp->bitbang.master); | |
296 | ||
297 | return 0; | |
298 | } | |
299 | ||
300 | static void ath79_spi_shutdown(struct platform_device *pdev) | |
301 | { | |
302 | ath79_spi_remove(pdev); | |
303 | } | |
304 | ||
305 | static struct platform_driver ath79_spi_driver = { | |
306 | .probe = ath79_spi_probe, | |
307 | .remove = ath79_spi_remove, | |
308 | .shutdown = ath79_spi_shutdown, | |
309 | .driver = { | |
310 | .name = DRV_NAME, | |
311 | .owner = THIS_MODULE, | |
312 | }, | |
313 | }; | |
314 | module_platform_driver(ath79_spi_driver); | |
315 | ||
316 | MODULE_DESCRIPTION("SPI controller driver for Atheros AR71XX/AR724X/AR913X"); | |
317 | MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); | |
318 | MODULE_LICENSE("GPL v2"); | |
319 | MODULE_ALIAS("platform:" DRV_NAME); |