4 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
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>
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.
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>
26 #define DRV_NAME "spi_altera"
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
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
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
49 /* bitbang has to be first */
50 struct spi_bitbang bitbang;
51 struct completion done;
61 const unsigned char *tx;
65 static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
67 return spi_master_get_devdata(sdev->master);
70 static void altera_spi_chipsel(struct spi_device *spi, int value)
72 struct altera_spi *hw = altera_spi_to_hw(spi);
74 if (spi->mode & SPI_CS_HIGH) {
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);
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);
91 case BITBANG_CS_INACTIVE:
92 hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
93 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
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);
106 static int altera_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
111 static int altera_spi_setup(struct spi_device *spi)
116 static inline unsigned int hw_txbyte(struct altera_spi *hw, int count)
119 switch (hw->bytes_per_word) {
121 return hw->tx[count];
123 return (hw->tx[count * 2]
124 | (hw->tx[count * 2 + 1] << 8));
130 static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
132 struct altera_spi *hw = altera_spi_to_hw(spi);
137 hw->bytes_per_word = t->bits_per_word / 8;
138 hw->len = t->len / hw->bytes_per_word;
141 /* enable receive interrupt */
142 hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
143 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
145 /* send the first byte */
146 writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
148 wait_for_completion(&hw->done);
149 /* disable receive interrupt */
150 hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
151 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
153 while (hw->count < hw->len) {
156 writel(hw_txbyte(hw, hw->count),
157 hw->base + ALTERA_SPI_TXDATA);
159 while (!(readl(hw->base + ALTERA_SPI_STATUS) &
160 ALTERA_SPI_STATUS_RRDY_MSK))
163 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
165 switch (hw->bytes_per_word) {
167 hw->rx[hw->count] = rxd;
170 hw->rx[hw->count * 2] = rxd;
171 hw->rx[hw->count * 2 + 1] = rxd >> 8;
180 return hw->count * hw->bytes_per_word;
183 static irqreturn_t altera_spi_irq(int irq, void *dev)
185 struct altera_spi *hw = dev;
188 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
190 switch (hw->bytes_per_word) {
192 hw->rx[hw->count] = rxd;
195 hw->rx[hw->count * 2] = rxd;
196 hw->rx[hw->count * 2 + 1] = rxd >> 8;
203 if (hw->count < hw->len)
204 writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
211 static int altera_spi_probe(struct platform_device *pdev)
213 struct altera_spi_platform_data *platp = pdev->dev.platform_data;
214 struct altera_spi *hw;
215 struct spi_master *master;
216 struct resource *res;
219 master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
223 /* setup the master state. */
224 master->bus_num = pdev->id;
225 master->num_chipselect = 16;
226 master->mode_bits = SPI_CS_HIGH;
227 master->setup = altera_spi_setup;
229 hw = spi_master_get_devdata(master);
230 platform_set_drvdata(pdev, hw);
232 /* setup the state for the bitbang driver */
233 hw->bitbang.master = spi_master_get(master);
234 if (!hw->bitbang.master)
236 hw->bitbang.setup_transfer = altera_spi_setupxfer;
237 hw->bitbang.chipselect = altera_spi_chipsel;
238 hw->bitbang.txrx_bufs = altera_spi_txrx;
240 /* find and map our resources */
241 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
242 hw->base = devm_ioremap_resource(&pdev->dev, res);
243 if (IS_ERR(hw->base)) {
244 err = PTR_ERR(hw->base);
247 /* program defaults into the registers */
248 hw->imr = 0; /* disable spi interrupts */
249 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
250 writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
251 if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
252 readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
253 /* irq is optional */
254 hw->irq = platform_get_irq(pdev, 0);
256 init_completion(&hw->done);
257 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
262 /* find platform data */
264 hw->bitbang.master->dev.of_node = pdev->dev.of_node;
266 /* register our spi controller */
267 err = spi_bitbang_start(&hw->bitbang);
270 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
274 spi_master_put(master);
278 static int altera_spi_remove(struct platform_device *dev)
280 struct altera_spi *hw = platform_get_drvdata(dev);
281 struct spi_master *master = hw->bitbang.master;
283 spi_bitbang_stop(&hw->bitbang);
284 spi_master_put(master);
289 static const struct of_device_id altera_spi_match[] = {
290 { .compatible = "ALTR,spi-1.0", },
293 MODULE_DEVICE_TABLE(of, altera_spi_match);
294 #endif /* CONFIG_OF */
296 static struct platform_driver altera_spi_driver = {
297 .probe = altera_spi_probe,
298 .remove = altera_spi_remove,
301 .owner = THIS_MODULE,
303 .of_match_table = of_match_ptr(altera_spi_match),
306 module_platform_driver(altera_spi_driver);
308 MODULE_DESCRIPTION("Altera SPI driver");
309 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
310 MODULE_LICENSE("GPL");
311 MODULE_ALIAS("platform:" DRV_NAME);