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Thomas Chou0b782532011-02-14 10:10:43 +08001/*
2 * Altera SPI driver
3 *
4 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
5 *
6 * Based on spi_s3c24xx.c, which is:
7 * Copyright (c) 2006 Ben Dooks
8 * Copyright (c) 2006 Simtec Electronics
9 * Ben Dooks <ben@simtec.co.uk>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16#include <linux/init.h>
17#include <linux/interrupt.h>
18#include <linux/errno.h>
Paul Gortmakerd7614de2011-07-03 15:44:29 -040019#include <linux/module.h>
Thomas Chou0b782532011-02-14 10:10:43 +080020#include <linux/platform_device.h>
21#include <linux/spi/spi.h>
22#include <linux/spi/spi_bitbang.h>
23#include <linux/io.h>
24#include <linux/of.h>
25
26#define DRV_NAME "spi_altera"
27
28#define ALTERA_SPI_RXDATA 0
29#define ALTERA_SPI_TXDATA 4
30#define ALTERA_SPI_STATUS 8
31#define ALTERA_SPI_CONTROL 12
32#define ALTERA_SPI_SLAVE_SEL 20
33
34#define ALTERA_SPI_STATUS_ROE_MSK 0x8
35#define ALTERA_SPI_STATUS_TOE_MSK 0x10
36#define ALTERA_SPI_STATUS_TMT_MSK 0x20
37#define ALTERA_SPI_STATUS_TRDY_MSK 0x40
38#define ALTERA_SPI_STATUS_RRDY_MSK 0x80
39#define ALTERA_SPI_STATUS_E_MSK 0x100
40
41#define ALTERA_SPI_CONTROL_IROE_MSK 0x8
42#define ALTERA_SPI_CONTROL_ITOE_MSK 0x10
43#define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40
44#define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80
45#define ALTERA_SPI_CONTROL_IE_MSK 0x100
46#define ALTERA_SPI_CONTROL_SSO_MSK 0x400
47
48struct altera_spi {
49 /* bitbang has to be first */
50 struct spi_bitbang bitbang;
51 struct completion done;
52
53 void __iomem *base;
54 int irq;
55 int len;
56 int count;
57 int bytes_per_word;
58 unsigned long imr;
59
60 /* data buffers */
61 const unsigned char *tx;
62 unsigned char *rx;
63};
64
65static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
66{
67 return spi_master_get_devdata(sdev->master);
68}
69
70static void altera_spi_chipsel(struct spi_device *spi, int value)
71{
72 struct altera_spi *hw = altera_spi_to_hw(spi);
73
74 if (spi->mode & SPI_CS_HIGH) {
75 switch (value) {
76 case BITBANG_CS_INACTIVE:
77 writel(1 << spi->chip_select,
78 hw->base + ALTERA_SPI_SLAVE_SEL);
79 hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
80 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
81 break;
82
83 case BITBANG_CS_ACTIVE:
84 hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
85 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
86 writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
87 break;
88 }
89 } else {
90 switch (value) {
91 case BITBANG_CS_INACTIVE:
92 hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
93 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
94 break;
95
96 case BITBANG_CS_ACTIVE:
97 writel(1 << spi->chip_select,
98 hw->base + ALTERA_SPI_SLAVE_SEL);
99 hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
100 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
101 break;
102 }
103 }
104}
105
Thomas Chou0b782532011-02-14 10:10:43 +0800106static inline unsigned int hw_txbyte(struct altera_spi *hw, int count)
107{
108 if (hw->tx) {
109 switch (hw->bytes_per_word) {
110 case 1:
111 return hw->tx[count];
112 case 2:
113 return (hw->tx[count * 2]
114 | (hw->tx[count * 2 + 1] << 8));
115 }
116 }
117 return 0;
118}
119
120static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
121{
122 struct altera_spi *hw = altera_spi_to_hw(spi);
123
124 hw->tx = t->tx_buf;
125 hw->rx = t->rx_buf;
126 hw->count = 0;
Axel Linf073d372013-08-29 23:41:20 +0800127 hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
Thomas Chou0b782532011-02-14 10:10:43 +0800128 hw->len = t->len / hw->bytes_per_word;
129
130 if (hw->irq >= 0) {
131 /* enable receive interrupt */
132 hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
133 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
134
135 /* send the first byte */
136 writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
137
138 wait_for_completion(&hw->done);
139 /* disable receive interrupt */
140 hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
141 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
142 } else {
Axel Lin72be0ee2013-08-15 14:18:46 +0800143 while (hw->count < hw->len) {
Thomas Chou0b782532011-02-14 10:10:43 +0800144 unsigned int rxd;
145
Axel Lin72be0ee2013-08-15 14:18:46 +0800146 writel(hw_txbyte(hw, hw->count),
147 hw->base + ALTERA_SPI_TXDATA);
148
Thomas Chou0b782532011-02-14 10:10:43 +0800149 while (!(readl(hw->base + ALTERA_SPI_STATUS) &
150 ALTERA_SPI_STATUS_RRDY_MSK))
151 cpu_relax();
152
153 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
154 if (hw->rx) {
155 switch (hw->bytes_per_word) {
156 case 1:
157 hw->rx[hw->count] = rxd;
158 break;
159 case 2:
160 hw->rx[hw->count * 2] = rxd;
161 hw->rx[hw->count * 2 + 1] = rxd >> 8;
162 break;
163 }
164 }
165
166 hw->count++;
Thomas Chou0b782532011-02-14 10:10:43 +0800167 }
Thomas Chou0b782532011-02-14 10:10:43 +0800168 }
169
170 return hw->count * hw->bytes_per_word;
171}
172
173static irqreturn_t altera_spi_irq(int irq, void *dev)
174{
175 struct altera_spi *hw = dev;
176 unsigned int rxd;
177
178 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
179 if (hw->rx) {
180 switch (hw->bytes_per_word) {
181 case 1:
182 hw->rx[hw->count] = rxd;
183 break;
184 case 2:
185 hw->rx[hw->count * 2] = rxd;
186 hw->rx[hw->count * 2 + 1] = rxd >> 8;
187 break;
188 }
189 }
190
191 hw->count++;
192
193 if (hw->count < hw->len)
194 writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
195 else
196 complete(&hw->done);
197
198 return IRQ_HANDLED;
199}
200
Grant Likelyfd4a3192012-12-07 16:57:14 +0000201static int altera_spi_probe(struct platform_device *pdev)
Thomas Chou0b782532011-02-14 10:10:43 +0800202{
Jingoo Han8074cf02013-07-30 16:58:59 +0900203 struct altera_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
Thomas Chou0b782532011-02-14 10:10:43 +0800204 struct altera_spi *hw;
205 struct spi_master *master;
206 struct resource *res;
207 int err = -ENODEV;
208
209 master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
210 if (!master)
211 return err;
212
213 /* setup the master state. */
214 master->bus_num = pdev->id;
215 master->num_chipselect = 16;
216 master->mode_bits = SPI_CS_HIGH;
Thomas Chou0b782532011-02-14 10:10:43 +0800217
218 hw = spi_master_get_devdata(master);
219 platform_set_drvdata(pdev, hw);
220
221 /* setup the state for the bitbang driver */
222 hw->bitbang.master = spi_master_get(master);
223 if (!hw->bitbang.master)
224 return err;
Thomas Chou0b782532011-02-14 10:10:43 +0800225 hw->bitbang.chipselect = altera_spi_chipsel;
226 hw->bitbang.txrx_bufs = altera_spi_txrx;
227
228 /* find and map our resources */
229 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Julia Lawallb3136f82013-08-24 19:13:15 +0200230 hw->base = devm_ioremap_resource(&pdev->dev, res);
231 if (IS_ERR(hw->base)) {
232 err = PTR_ERR(hw->base);
233 goto exit;
234 }
Thomas Chou0b782532011-02-14 10:10:43 +0800235 /* program defaults into the registers */
236 hw->imr = 0; /* disable spi interrupts */
237 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
238 writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
239 if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
240 readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
241 /* irq is optional */
242 hw->irq = platform_get_irq(pdev, 0);
243 if (hw->irq >= 0) {
244 init_completion(&hw->done);
245 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
246 pdev->name, hw);
247 if (err)
248 goto exit;
249 }
250 /* find platform data */
251 if (!platp)
252 hw->bitbang.master->dev.of_node = pdev->dev.of_node;
253
254 /* register our spi controller */
255 err = spi_bitbang_start(&hw->bitbang);
256 if (err)
257 goto exit;
258 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
259
260 return 0;
Thomas Chou0b782532011-02-14 10:10:43 +0800261exit:
Thomas Chou0b782532011-02-14 10:10:43 +0800262 spi_master_put(master);
263 return err;
264}
265
Grant Likelyfd4a3192012-12-07 16:57:14 +0000266static int altera_spi_remove(struct platform_device *dev)
Thomas Chou0b782532011-02-14 10:10:43 +0800267{
268 struct altera_spi *hw = platform_get_drvdata(dev);
269 struct spi_master *master = hw->bitbang.master;
270
271 spi_bitbang_stop(&hw->bitbang);
Thomas Chou0b782532011-02-14 10:10:43 +0800272 spi_master_put(master);
273 return 0;
274}
275
276#ifdef CONFIG_OF
277static const struct of_device_id altera_spi_match[] = {
278 { .compatible = "ALTR,spi-1.0", },
Dinh Nguyen13960b42013-08-14 15:25:19 -0500279 { .compatible = "altr,spi-1.0", },
Thomas Chou0b782532011-02-14 10:10:43 +0800280 {},
281};
282MODULE_DEVICE_TABLE(of, altera_spi_match);
Thomas Chou0b782532011-02-14 10:10:43 +0800283#endif /* CONFIG_OF */
284
285static struct platform_driver altera_spi_driver = {
286 .probe = altera_spi_probe,
Grant Likelyfd4a3192012-12-07 16:57:14 +0000287 .remove = altera_spi_remove,
Thomas Chou0b782532011-02-14 10:10:43 +0800288 .driver = {
289 .name = DRV_NAME,
290 .owner = THIS_MODULE,
291 .pm = NULL,
Tobias Klauser89f98dc2012-08-15 09:30:28 +0200292 .of_match_table = of_match_ptr(altera_spi_match),
Thomas Chou0b782532011-02-14 10:10:43 +0800293 },
294};
Grant Likely940ab882011-10-05 11:29:49 -0600295module_platform_driver(altera_spi_driver);
Thomas Chou0b782532011-02-14 10:10:43 +0800296
297MODULE_DESCRIPTION("Altera SPI driver");
298MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
299MODULE_LICENSE("GPL");
300MODULE_ALIAS("platform:" DRV_NAME);