2 * Xtensa xtfpga SPI controller driver
4 * Copyright (c) 2014 Cadence Design Systems Inc.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/delay.h>
13 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/spi/spi.h>
17 #include <linux/spi/spi_bitbang.h>
19 #define XTFPGA_SPI_NAME "xtfpga_spi"
21 #define XTFPGA_SPI_START 0x0
22 #define XTFPGA_SPI_BUSY 0x4
23 #define XTFPGA_SPI_DATA 0x8
25 #define BUSY_WAIT_US 100
28 struct spi_bitbang bitbang
;
34 static inline void xtfpga_spi_write32(const struct xtfpga_spi
*spi
,
35 unsigned addr
, u32 val
)
37 iowrite32(val
, spi
->regs
+ addr
);
40 static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi
*spi
,
43 return ioread32(spi
->regs
+ addr
);
46 static inline void xtfpga_spi_wait_busy(struct xtfpga_spi
*xspi
)
49 for (i
= 0; xtfpga_spi_read32(xspi
, XTFPGA_SPI_BUSY
) &&
50 i
< BUSY_WAIT_US
; ++i
)
52 WARN_ON_ONCE(i
== BUSY_WAIT_US
);
55 static u32
xtfpga_spi_txrx_word(struct spi_device
*spi
, unsigned nsecs
,
58 struct xtfpga_spi
*xspi
= spi_master_get_devdata(spi
->master
);
60 xspi
->data
= (xspi
->data
<< bits
) | (v
& GENMASK(bits
- 1, 0));
61 xspi
->data_sz
+= bits
;
62 if (xspi
->data_sz
>= 16) {
63 xtfpga_spi_write32(xspi
, XTFPGA_SPI_DATA
,
64 xspi
->data
>> (xspi
->data_sz
- 16));
66 xtfpga_spi_write32(xspi
, XTFPGA_SPI_START
, 1);
67 xtfpga_spi_wait_busy(xspi
);
68 xtfpga_spi_write32(xspi
, XTFPGA_SPI_START
, 0);
74 static void xtfpga_spi_chipselect(struct spi_device
*spi
, int is_on
)
76 struct xtfpga_spi
*xspi
= spi_master_get_devdata(spi
->master
);
78 WARN_ON(xspi
->data_sz
!= 0);
82 static int xtfpga_spi_probe(struct platform_device
*pdev
)
84 struct xtfpga_spi
*xspi
;
87 struct spi_master
*master
;
89 master
= spi_alloc_master(&pdev
->dev
, sizeof(struct xtfpga_spi
));
93 master
->flags
= SPI_MASTER_NO_RX
;
94 master
->bits_per_word_mask
= SPI_BPW_RANGE_MASK(1, 16);
95 master
->bus_num
= pdev
->dev
.id
;
96 master
->dev
.of_node
= pdev
->dev
.of_node
;
98 xspi
= spi_master_get_devdata(master
);
99 xspi
->bitbang
.master
= master
;
100 xspi
->bitbang
.chipselect
= xtfpga_spi_chipselect
;
101 xspi
->bitbang
.txrx_word
[SPI_MODE_0
] = xtfpga_spi_txrx_word
;
103 mem
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
105 dev_err(&pdev
->dev
, "No memory resource\n");
109 xspi
->regs
= devm_ioremap_resource(&pdev
->dev
, mem
);
110 if (IS_ERR(xspi
->regs
)) {
111 ret
= PTR_ERR(xspi
->regs
);
115 xtfpga_spi_write32(xspi
, XTFPGA_SPI_START
, 0);
116 usleep_range(1000, 2000);
117 if (xtfpga_spi_read32(xspi
, XTFPGA_SPI_BUSY
)) {
118 dev_err(&pdev
->dev
, "Device stuck in busy state\n");
123 ret
= spi_bitbang_start(&xspi
->bitbang
);
125 dev_err(&pdev
->dev
, "spi_bitbang_start failed\n");
129 platform_set_drvdata(pdev
, master
);
132 spi_master_put(master
);
136 static int xtfpga_spi_remove(struct platform_device
*pdev
)
138 struct spi_master
*master
= platform_get_drvdata(pdev
);
139 struct xtfpga_spi
*xspi
= spi_master_get_devdata(master
);
141 spi_bitbang_stop(&xspi
->bitbang
);
142 spi_master_put(master
);
147 MODULE_ALIAS("platform:" XTFPGA_SPI_NAME
);
150 static const struct of_device_id xtfpga_spi_of_match
[] = {
151 { .compatible
= "cdns,xtfpga-spi", },
154 MODULE_DEVICE_TABLE(of
, xtfpga_spi_of_match
);
157 static struct platform_driver xtfpga_spi_driver
= {
158 .probe
= xtfpga_spi_probe
,
159 .remove
= xtfpga_spi_remove
,
161 .name
= XTFPGA_SPI_NAME
,
162 .owner
= THIS_MODULE
,
163 .of_match_table
= of_match_ptr(xtfpga_spi_of_match
),
166 module_platform_driver(xtfpga_spi_driver
);
168 MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
169 MODULE_DESCRIPTION("xtensa xtfpga SPI driver");
170 MODULE_LICENSE("GPL");