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/interrupt.h>
17 #include <linux/errno.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/spi/spi.h>
24 #define DRV_NAME "spi_altera"
26 #define ALTERA_SPI_RXDATA 0
27 #define ALTERA_SPI_TXDATA 4
28 #define ALTERA_SPI_STATUS 8
29 #define ALTERA_SPI_CONTROL 12
30 #define ALTERA_SPI_SLAVE_SEL 20
32 #define ALTERA_SPI_STATUS_ROE_MSK 0x8
33 #define ALTERA_SPI_STATUS_TOE_MSK 0x10
34 #define ALTERA_SPI_STATUS_TMT_MSK 0x20
35 #define ALTERA_SPI_STATUS_TRDY_MSK 0x40
36 #define ALTERA_SPI_STATUS_RRDY_MSK 0x80
37 #define ALTERA_SPI_STATUS_E_MSK 0x100
39 #define ALTERA_SPI_CONTROL_IROE_MSK 0x8
40 #define ALTERA_SPI_CONTROL_ITOE_MSK 0x10
41 #define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40
42 #define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80
43 #define ALTERA_SPI_CONTROL_IE_MSK 0x100
44 #define ALTERA_SPI_CONTROL_SSO_MSK 0x400
55 const unsigned char *tx;
59 static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
61 return spi_master_get_devdata(sdev->master);
64 static void altera_spi_set_cs(struct spi_device *spi, bool is_high)
66 struct altera_spi *hw = altera_spi_to_hw(spi);
69 hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
70 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
71 writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
73 writel(BIT(spi->chip_select), hw->base + ALTERA_SPI_SLAVE_SEL);
74 hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
75 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
79 static inline unsigned int hw_txbyte(struct altera_spi *hw, int count)
82 switch (hw->bytes_per_word) {
86 return (hw->tx[count * 2]
87 | (hw->tx[count * 2 + 1] << 8));
93 static int altera_spi_txrx(struct spi_master *master,
94 struct spi_device *spi, struct spi_transfer *t)
96 struct altera_spi *hw = spi_master_get_devdata(master);
101 hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
102 hw->len = t->len / hw->bytes_per_word;
105 /* enable receive interrupt */
106 hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
107 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
109 /* send the first byte */
110 writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
112 while (hw->count < hw->len) {
115 writel(hw_txbyte(hw, hw->count),
116 hw->base + ALTERA_SPI_TXDATA);
118 while (!(readl(hw->base + ALTERA_SPI_STATUS) &
119 ALTERA_SPI_STATUS_RRDY_MSK))
122 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
124 switch (hw->bytes_per_word) {
126 hw->rx[hw->count] = rxd;
129 hw->rx[hw->count * 2] = rxd;
130 hw->rx[hw->count * 2 + 1] = rxd >> 8;
137 spi_finalize_current_transfer(master);
143 static irqreturn_t altera_spi_irq(int irq, void *dev)
145 struct spi_master *master = dev;
146 struct altera_spi *hw = spi_master_get_devdata(master);
149 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
151 switch (hw->bytes_per_word) {
153 hw->rx[hw->count] = rxd;
156 hw->rx[hw->count * 2] = rxd;
157 hw->rx[hw->count * 2 + 1] = rxd >> 8;
164 if (hw->count < hw->len) {
165 writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
167 /* disable receive interrupt */
168 hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
169 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
171 spi_finalize_current_transfer(master);
177 static int altera_spi_probe(struct platform_device *pdev)
179 struct altera_spi *hw;
180 struct spi_master *master;
181 struct resource *res;
184 master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
188 /* setup the master state. */
189 master->bus_num = pdev->id;
190 master->num_chipselect = 16;
191 master->mode_bits = SPI_CS_HIGH;
192 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
193 master->dev.of_node = pdev->dev.of_node;
194 master->transfer_one = altera_spi_txrx;
195 master->set_cs = altera_spi_set_cs;
197 hw = spi_master_get_devdata(master);
199 /* find and map our resources */
200 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
201 hw->base = devm_ioremap_resource(&pdev->dev, res);
202 if (IS_ERR(hw->base)) {
203 err = PTR_ERR(hw->base);
206 /* program defaults into the registers */
207 hw->imr = 0; /* disable spi interrupts */
208 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
209 writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
210 if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
211 readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
212 /* irq is optional */
213 hw->irq = platform_get_irq(pdev, 0);
215 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
221 err = devm_spi_register_master(&pdev->dev, master);
224 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
228 spi_master_put(master);
233 static const struct of_device_id altera_spi_match[] = {
234 { .compatible = "ALTR,spi-1.0", },
235 { .compatible = "altr,spi-1.0", },
238 MODULE_DEVICE_TABLE(of, altera_spi_match);
239 #endif /* CONFIG_OF */
241 static struct platform_driver altera_spi_driver = {
242 .probe = altera_spi_probe,
246 .of_match_table = of_match_ptr(altera_spi_match),
249 module_platform_driver(altera_spi_driver);
251 MODULE_DESCRIPTION("Altera SPI driver");
252 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
253 MODULE_LICENSE("GPL");
254 MODULE_ALIAS("platform:" DRV_NAME);