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0b782531 TC |
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 | ||
0b782531 TC |
16 | #include <linux/interrupt.h> |
17 | #include <linux/errno.h> | |
d7614de4 | 18 | #include <linux/module.h> |
0b782531 TC |
19 | #include <linux/platform_device.h> |
20 | #include <linux/spi/spi.h> | |
0b782531 TC |
21 | #include <linux/io.h> |
22 | #include <linux/of.h> | |
23 | ||
24 | #define DRV_NAME "spi_altera" | |
25 | ||
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 | |
31 | ||
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 | |
38 | ||
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 | |
45 | ||
46 | struct altera_spi { | |
0b782531 TC |
47 | void __iomem *base; |
48 | int irq; | |
49 | int len; | |
50 | int count; | |
51 | int bytes_per_word; | |
52 | unsigned long imr; | |
53 | ||
54 | /* data buffers */ | |
55 | const unsigned char *tx; | |
56 | unsigned char *rx; | |
57 | }; | |
58 | ||
59 | static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev) | |
60 | { | |
61 | return spi_master_get_devdata(sdev->master); | |
62 | } | |
63 | ||
e19b63cd | 64 | static void altera_spi_set_cs(struct spi_device *spi, bool is_high) |
0b782531 TC |
65 | { |
66 | struct altera_spi *hw = altera_spi_to_hw(spi); | |
67 | ||
e19b63cd LPC |
68 | if (is_high) { |
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); | |
0b782531 | 72 | } else { |
e19b63cd LPC |
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); | |
0b782531 TC |
76 | } |
77 | } | |
78 | ||
b64836a5 | 79 | static void altera_spi_tx_word(struct altera_spi *hw) |
0b782531 | 80 | { |
b64836a5 LPC |
81 | unsigned int txd = 0; |
82 | ||
0b782531 TC |
83 | if (hw->tx) { |
84 | switch (hw->bytes_per_word) { | |
85 | case 1: | |
b64836a5 LPC |
86 | txd = hw->tx[hw->count]; |
87 | break; | |
0b782531 | 88 | case 2: |
b64836a5 LPC |
89 | txd = (hw->tx[hw->count * 2] |
90 | | (hw->tx[hw->count * 2 + 1] << 8)); | |
91 | break; | |
0b782531 TC |
92 | } |
93 | } | |
b64836a5 LPC |
94 | |
95 | writel(txd, hw->base + ALTERA_SPI_TXDATA); | |
96 | } | |
97 | ||
98 | static void altera_spi_rx_word(struct altera_spi *hw) | |
99 | { | |
100 | unsigned int rxd; | |
101 | ||
102 | rxd = readl(hw->base + ALTERA_SPI_RXDATA); | |
103 | if (hw->rx) { | |
104 | switch (hw->bytes_per_word) { | |
105 | case 1: | |
106 | hw->rx[hw->count] = rxd; | |
107 | break; | |
108 | case 2: | |
109 | hw->rx[hw->count * 2] = rxd; | |
110 | hw->rx[hw->count * 2 + 1] = rxd >> 8; | |
111 | break; | |
112 | } | |
113 | } | |
114 | ||
115 | hw->count++; | |
0b782531 TC |
116 | } |
117 | ||
e19b63cd LPC |
118 | static int altera_spi_txrx(struct spi_master *master, |
119 | struct spi_device *spi, struct spi_transfer *t) | |
0b782531 | 120 | { |
e19b63cd | 121 | struct altera_spi *hw = spi_master_get_devdata(master); |
0b782531 TC |
122 | |
123 | hw->tx = t->tx_buf; | |
124 | hw->rx = t->rx_buf; | |
125 | hw->count = 0; | |
f073d37d | 126 | hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8); |
0b782531 TC |
127 | hw->len = t->len / hw->bytes_per_word; |
128 | ||
129 | if (hw->irq >= 0) { | |
130 | /* enable receive interrupt */ | |
131 | hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK; | |
132 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
133 | ||
134 | /* send the first byte */ | |
b64836a5 | 135 | altera_spi_tx_word(hw); |
0b782531 | 136 | } else { |
72be0ee4 | 137 | while (hw->count < hw->len) { |
b64836a5 | 138 | altera_spi_tx_word(hw); |
72be0ee4 | 139 | |
0b782531 TC |
140 | while (!(readl(hw->base + ALTERA_SPI_STATUS) & |
141 | ALTERA_SPI_STATUS_RRDY_MSK)) | |
142 | cpu_relax(); | |
143 | ||
b64836a5 | 144 | altera_spi_rx_word(hw); |
0b782531 | 145 | } |
e19b63cd | 146 | spi_finalize_current_transfer(master); |
0b782531 TC |
147 | } |
148 | ||
e19b63cd | 149 | return t->len; |
0b782531 TC |
150 | } |
151 | ||
152 | static irqreturn_t altera_spi_irq(int irq, void *dev) | |
153 | { | |
e19b63cd LPC |
154 | struct spi_master *master = dev; |
155 | struct altera_spi *hw = spi_master_get_devdata(master); | |
0b782531 | 156 | |
b64836a5 | 157 | altera_spi_rx_word(hw); |
0b782531 | 158 | |
e19b63cd | 159 | if (hw->count < hw->len) { |
b64836a5 | 160 | altera_spi_tx_word(hw); |
e19b63cd LPC |
161 | } else { |
162 | /* disable receive interrupt */ | |
163 | hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK; | |
164 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
165 | ||
166 | spi_finalize_current_transfer(master); | |
167 | } | |
0b782531 TC |
168 | |
169 | return IRQ_HANDLED; | |
170 | } | |
171 | ||
fd4a319b | 172 | static int altera_spi_probe(struct platform_device *pdev) |
0b782531 | 173 | { |
0b782531 TC |
174 | struct altera_spi *hw; |
175 | struct spi_master *master; | |
176 | struct resource *res; | |
177 | int err = -ENODEV; | |
178 | ||
179 | master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi)); | |
180 | if (!master) | |
181 | return err; | |
182 | ||
183 | /* setup the master state. */ | |
184 | master->bus_num = pdev->id; | |
185 | master->num_chipselect = 16; | |
186 | master->mode_bits = SPI_CS_HIGH; | |
72bb79d0 | 187 | master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16); |
bf2f2f79 | 188 | master->dev.of_node = pdev->dev.of_node; |
e19b63cd LPC |
189 | master->transfer_one = altera_spi_txrx; |
190 | master->set_cs = altera_spi_set_cs; | |
0b782531 TC |
191 | |
192 | hw = spi_master_get_devdata(master); | |
0b782531 TC |
193 | |
194 | /* find and map our resources */ | |
195 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
b3136f8f JL |
196 | hw->base = devm_ioremap_resource(&pdev->dev, res); |
197 | if (IS_ERR(hw->base)) { | |
198 | err = PTR_ERR(hw->base); | |
199 | goto exit; | |
200 | } | |
0b782531 TC |
201 | /* program defaults into the registers */ |
202 | hw->imr = 0; /* disable spi interrupts */ | |
203 | writel(hw->imr, hw->base + ALTERA_SPI_CONTROL); | |
204 | writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */ | |
205 | if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK) | |
206 | readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */ | |
207 | /* irq is optional */ | |
208 | hw->irq = platform_get_irq(pdev, 0); | |
209 | if (hw->irq >= 0) { | |
0b782531 | 210 | err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0, |
e19b63cd | 211 | pdev->name, master); |
0b782531 TC |
212 | if (err) |
213 | goto exit; | |
214 | } | |
0b782531 | 215 | |
e19b63cd | 216 | err = devm_spi_register_master(&pdev->dev, master); |
0b782531 TC |
217 | if (err) |
218 | goto exit; | |
219 | dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq); | |
220 | ||
221 | return 0; | |
0b782531 | 222 | exit: |
0b782531 TC |
223 | spi_master_put(master); |
224 | return err; | |
225 | } | |
226 | ||
0b782531 TC |
227 | #ifdef CONFIG_OF |
228 | static const struct of_device_id altera_spi_match[] = { | |
229 | { .compatible = "ALTR,spi-1.0", }, | |
13960b47 | 230 | { .compatible = "altr,spi-1.0", }, |
0b782531 TC |
231 | {}, |
232 | }; | |
233 | MODULE_DEVICE_TABLE(of, altera_spi_match); | |
0b782531 TC |
234 | #endif /* CONFIG_OF */ |
235 | ||
236 | static struct platform_driver altera_spi_driver = { | |
237 | .probe = altera_spi_probe, | |
0b782531 TC |
238 | .driver = { |
239 | .name = DRV_NAME, | |
0b782531 | 240 | .pm = NULL, |
89f98dc5 | 241 | .of_match_table = of_match_ptr(altera_spi_match), |
0b782531 TC |
242 | }, |
243 | }; | |
940ab889 | 244 | module_platform_driver(altera_spi_driver); |
0b782531 TC |
245 | |
246 | MODULE_DESCRIPTION("Altera SPI driver"); | |
247 | MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>"); | |
248 | MODULE_LICENSE("GPL"); | |
249 | MODULE_ALIAS("platform:" DRV_NAME); |