This source file includes following definitions.
- altera_spi_to_hw
- altera_spi_set_cs
- altera_spi_tx_word
- altera_spi_rx_word
- altera_spi_txrx
- altera_spi_irq
- altera_spi_probe
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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>
18 #include <linux/io.h>
19 #include <linux/of.h>
20
21 #define DRV_NAME "spi_altera"
22
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
28
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
35
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
42
43 struct altera_spi {
44 void __iomem *base;
45 int irq;
46 int len;
47 int count;
48 int bytes_per_word;
49 unsigned long imr;
50
51
52 const unsigned char *tx;
53 unsigned char *rx;
54 };
55
56 static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
57 {
58 return spi_master_get_devdata(sdev->master);
59 }
60
61 static void altera_spi_set_cs(struct spi_device *spi, bool is_high)
62 {
63 struct altera_spi *hw = altera_spi_to_hw(spi);
64
65 if (is_high) {
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);
69 } else {
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);
73 }
74 }
75
76 static void altera_spi_tx_word(struct altera_spi *hw)
77 {
78 unsigned int txd = 0;
79
80 if (hw->tx) {
81 switch (hw->bytes_per_word) {
82 case 1:
83 txd = hw->tx[hw->count];
84 break;
85 case 2:
86 txd = (hw->tx[hw->count * 2]
87 | (hw->tx[hw->count * 2 + 1] << 8));
88 break;
89 }
90 }
91
92 writel(txd, hw->base + ALTERA_SPI_TXDATA);
93 }
94
95 static void altera_spi_rx_word(struct altera_spi *hw)
96 {
97 unsigned int rxd;
98
99 rxd = readl(hw->base + ALTERA_SPI_RXDATA);
100 if (hw->rx) {
101 switch (hw->bytes_per_word) {
102 case 1:
103 hw->rx[hw->count] = rxd;
104 break;
105 case 2:
106 hw->rx[hw->count * 2] = rxd;
107 hw->rx[hw->count * 2 + 1] = rxd >> 8;
108 break;
109 }
110 }
111
112 hw->count++;
113 }
114
115 static int altera_spi_txrx(struct spi_master *master,
116 struct spi_device *spi, struct spi_transfer *t)
117 {
118 struct altera_spi *hw = spi_master_get_devdata(master);
119
120 hw->tx = t->tx_buf;
121 hw->rx = t->rx_buf;
122 hw->count = 0;
123 hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
124 hw->len = t->len / hw->bytes_per_word;
125
126 if (hw->irq >= 0) {
127
128 hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
129 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
130
131
132 altera_spi_tx_word(hw);
133 } else {
134 while (hw->count < hw->len) {
135 altera_spi_tx_word(hw);
136
137 while (!(readl(hw->base + ALTERA_SPI_STATUS) &
138 ALTERA_SPI_STATUS_RRDY_MSK))
139 cpu_relax();
140
141 altera_spi_rx_word(hw);
142 }
143 spi_finalize_current_transfer(master);
144 }
145
146 return t->len;
147 }
148
149 static irqreturn_t altera_spi_irq(int irq, void *dev)
150 {
151 struct spi_master *master = dev;
152 struct altera_spi *hw = spi_master_get_devdata(master);
153
154 altera_spi_rx_word(hw);
155
156 if (hw->count < hw->len) {
157 altera_spi_tx_word(hw);
158 } else {
159
160 hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
161 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
162
163 spi_finalize_current_transfer(master);
164 }
165
166 return IRQ_HANDLED;
167 }
168
169 static int altera_spi_probe(struct platform_device *pdev)
170 {
171 struct altera_spi *hw;
172 struct spi_master *master;
173 int err = -ENODEV;
174
175 master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
176 if (!master)
177 return err;
178
179
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;
187
188 hw = spi_master_get_devdata(master);
189
190
191 hw->base = devm_platform_ioremap_resource(pdev, 0);
192 if (IS_ERR(hw->base)) {
193 err = PTR_ERR(hw->base);
194 goto exit;
195 }
196
197 hw->imr = 0;
198 writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
199 writel(0, hw->base + ALTERA_SPI_STATUS);
200 if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
201 readl(hw->base + ALTERA_SPI_RXDATA);
202
203 hw->irq = platform_get_irq(pdev, 0);
204 if (hw->irq >= 0) {
205 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
206 pdev->name, master);
207 if (err)
208 goto exit;
209 }
210
211 err = devm_spi_register_master(&pdev->dev, master);
212 if (err)
213 goto exit;
214 dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
215
216 return 0;
217 exit:
218 spi_master_put(master);
219 return err;
220 }
221
222 #ifdef CONFIG_OF
223 static const struct of_device_id altera_spi_match[] = {
224 { .compatible = "ALTR,spi-1.0", },
225 { .compatible = "altr,spi-1.0", },
226 {},
227 };
228 MODULE_DEVICE_TABLE(of, altera_spi_match);
229 #endif
230
231 static struct platform_driver altera_spi_driver = {
232 .probe = altera_spi_probe,
233 .driver = {
234 .name = DRV_NAME,
235 .pm = NULL,
236 .of_match_table = of_match_ptr(altera_spi_match),
237 },
238 };
239 module_platform_driver(altera_spi_driver);
240
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);