Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

Linux/drivers/spi/spi-altera.c

  1 /*
  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>
 19 #include <linux/module.h>
 20 #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 
 48 struct 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 
 65 static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
 66 {
 67         return spi_master_get_devdata(sdev->master);
 68 }
 69 
 70 static 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 
106 static 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 
120 static 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;
127         hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
128         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 {
143                 while (hw->count < hw->len) {
144                         unsigned int rxd;
145 
146                         writel(hw_txbyte(hw, hw->count),
147                                hw->base + ALTERA_SPI_TXDATA);
148 
149                         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++;
167                 }
168         }
169 
170         return hw->count * hw->bytes_per_word;
171 }
172 
173 static 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 
201 static int altera_spi_probe(struct platform_device *pdev)
202 {
203         struct altera_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
204         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;
217 
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 = master;
223         hw->bitbang.chipselect = altera_spi_chipsel;
224         hw->bitbang.txrx_bufs = altera_spi_txrx;
225 
226         /* find and map our resources */
227         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
228         hw->base = devm_ioremap_resource(&pdev->dev, res);
229         if (IS_ERR(hw->base)) {
230                 err = PTR_ERR(hw->base);
231                 goto exit;
232         }
233         /* program defaults into the registers */
234         hw->imr = 0;            /* disable spi interrupts */
235         writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
236         writel(0, hw->base + ALTERA_SPI_STATUS);        /* clear status reg */
237         if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
238                 readl(hw->base + ALTERA_SPI_RXDATA);    /* flush rxdata */
239         /* irq is optional */
240         hw->irq = platform_get_irq(pdev, 0);
241         if (hw->irq >= 0) {
242                 init_completion(&hw->done);
243                 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
244                                        pdev->name, hw);
245                 if (err)
246                         goto exit;
247         }
248         /* find platform data */
249         if (!platp)
250                 hw->bitbang.master->dev.of_node = pdev->dev.of_node;
251 
252         /* register our spi controller */
253         err = spi_bitbang_start(&hw->bitbang);
254         if (err)
255                 goto exit;
256         dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
257 
258         return 0;
259 exit:
260         spi_master_put(master);
261         return err;
262 }
263 
264 static int altera_spi_remove(struct platform_device *dev)
265 {
266         struct altera_spi *hw = platform_get_drvdata(dev);
267         struct spi_master *master = hw->bitbang.master;
268 
269         spi_bitbang_stop(&hw->bitbang);
270         spi_master_put(master);
271         return 0;
272 }
273 
274 #ifdef CONFIG_OF
275 static const struct of_device_id altera_spi_match[] = {
276         { .compatible = "ALTR,spi-1.0", },
277         { .compatible = "altr,spi-1.0", },
278         {},
279 };
280 MODULE_DEVICE_TABLE(of, altera_spi_match);
281 #endif /* CONFIG_OF */
282 
283 static struct platform_driver altera_spi_driver = {
284         .probe = altera_spi_probe,
285         .remove = altera_spi_remove,
286         .driver = {
287                 .name = DRV_NAME,
288                 .owner = THIS_MODULE,
289                 .pm = NULL,
290                 .of_match_table = of_match_ptr(altera_spi_match),
291         },
292 };
293 module_platform_driver(altera_spi_driver);
294 
295 MODULE_DESCRIPTION("Altera SPI driver");
296 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
297 MODULE_LICENSE("GPL");
298 MODULE_ALIAS("platform:" DRV_NAME);
299 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us