1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
7 * Based on spi_s3c24xx.c, which is:
8 * Copyright (c) 2006 Ben Dooks
9 * Copyright (c) 2006 Simtec Electronics
10 * Ben Dooks <ben@simtec.co.uk>
13 #include <linux/interrupt.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/spi/spi.h>
21 #define DRV_NAME "spi_altera"
23 #define ALTERA_SPI_RXDATA 0
24 #define ALTERA_SPI_TXDATA 4
25 #define ALTERA_SPI_STATUS 8
26 #define ALTERA_SPI_CONTROL 12
27 #define ALTERA_SPI_SLAVE_SEL 20
29 #define ALTERA_SPI_STATUS_ROE_MSK 0x8
30 #define ALTERA_SPI_STATUS_TOE_MSK 0x10
31 #define ALTERA_SPI_STATUS_TMT_MSK 0x20
32 #define ALTERA_SPI_STATUS_TRDY_MSK 0x40
33 #define ALTERA_SPI_STATUS_RRDY_MSK 0x80
34 #define ALTERA_SPI_STATUS_E_MSK 0x100
36 #define ALTERA_SPI_CONTROL_IROE_MSK 0x8
37 #define ALTERA_SPI_CONTROL_ITOE_MSK 0x10
38 #define ALTERA_SPI_CONTROL_ITRDY_MSK 0x40
39 #define ALTERA_SPI_CONTROL_IRRDY_MSK 0x80
40 #define ALTERA_SPI_CONTROL_IE_MSK 0x100
41 #define ALTERA_SPI_CONTROL_SSO_MSK 0x400
52 const unsigned char *tx;
56 static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
58 return spi_master_get_devdata(sdev->master);
61 static void altera_spi_set_cs(struct spi_device *spi, bool is_high)
63 struct altera_spi *hw = altera_spi_to_hw(spi);
66 hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
67 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
68 writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
70 writel(BIT(spi->chip_select), hw->base + ALTERA_SPI_SLAVE_SEL);
71 hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
72 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
76 static void altera_spi_tx_word(struct altera_spi *hw)
81 switch (hw->bytes_per_word) {
83 txd = hw->tx[hw->count];
86 txd = (hw->tx[hw->count * 2]
87 | (hw->tx[hw->count * 2 + 1] << 8));
92 writel(txd, hw->base + ALTERA_SPI_TXDATA);
95 static void altera_spi_rx_word(struct altera_spi *hw)
99 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
101 switch (hw->bytes_per_word) {
103 hw->rx[hw->count] = rxd;
106 hw->rx[hw->count * 2] = rxd;
107 hw->rx[hw->count * 2 + 1] = rxd >> 8;
115 static int altera_spi_txrx(struct spi_master *master,
116 struct spi_device *spi, struct spi_transfer *t)
118 struct altera_spi *hw = spi_master_get_devdata(master);
123 hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
124 hw->len = t->len / hw->bytes_per_word;
127 /* enable receive interrupt */
128 hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
129 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
131 /* send the first byte */
132 altera_spi_tx_word(hw);
134 while (hw->count < hw->len) {
135 altera_spi_tx_word(hw);
137 while (!(readl(hw->base + ALTERA_SPI_STATUS) &
138 ALTERA_SPI_STATUS_RRDY_MSK))
141 altera_spi_rx_word(hw);
143 spi_finalize_current_transfer(master);
149 static irqreturn_t altera_spi_irq(int irq, void *dev)
151 struct spi_master *master = dev;
152 struct altera_spi *hw = spi_master_get_devdata(master);
154 altera_spi_rx_word(hw);
156 if (hw->count < hw->len) {
157 altera_spi_tx_word(hw);
159 /* disable receive interrupt */
160 hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
161 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
163 spi_finalize_current_transfer(master);
169 static int altera_spi_probe(struct platform_device *pdev)
171 struct altera_spi *hw;
172 struct spi_master *master;
175 master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
179 /* setup the master state. */
180 master->bus_num = pdev->id;
181 master->num_chipselect = 16;
182 master->mode_bits = SPI_CS_HIGH;
183 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
184 master->dev.of_node = pdev->dev.of_node;
185 master->transfer_one = altera_spi_txrx;
186 master->set_cs = altera_spi_set_cs;
188 hw = spi_master_get_devdata(master);
190 /* find and map our resources */
191 hw->base = devm_platform_ioremap_resource(pdev, 0);
192 if (IS_ERR(hw->base)) {
193 err = PTR_ERR(hw->base);
196 /* program defaults into the registers */
197 hw->imr = 0; /* disable spi interrupts */
198 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
199 writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
200 if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
201 readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
202 /* irq is optional */
203 hw->irq = platform_get_irq(pdev, 0);
205 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
211 err = devm_spi_register_master(&pdev->dev, master);
214 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
218 spi_master_put(master);
223 static const struct of_device_id altera_spi_match[] = {
224 { .compatible = "ALTR,spi-1.0", },
225 { .compatible = "altr,spi-1.0", },
228 MODULE_DEVICE_TABLE(of, altera_spi_match);
229 #endif /* CONFIG_OF */
231 static struct platform_driver altera_spi_driver = {
232 .probe = altera_spi_probe,
236 .of_match_table = of_match_ptr(altera_spi_match),
239 module_platform_driver(altera_spi_driver);
241 MODULE_DESCRIPTION("Altera SPI driver");
242 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
243 MODULE_LICENSE("GPL");
244 MODULE_ALIAS("platform:" DRV_NAME);