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11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/delay.h>
14#include <linux/spinlock.h>
15#include <linux/platform_device.h>
16#include <linux/io.h>
17#include <linux/spi/spi.h>
18#include <linux/spi/spi_bitbang.h>
19#include <linux/bitops.h>
20#include <linux/clk.h>
21#include <linux/err.h>
22#include <linux/platform_data/spi-ath79.h>
23
24#define DRV_NAME "ath79-spi"
25
26#define ATH79_SPI_RRW_DELAY_FACTOR 12000
27#define MHZ (1000 * 1000)
28
29#define AR71XX_SPI_REG_FS 0x00
30#define AR71XX_SPI_REG_CTRL 0x04
31#define AR71XX_SPI_REG_IOC 0x08
32#define AR71XX_SPI_REG_RDS 0x0c
33
34#define AR71XX_SPI_FS_GPIO BIT(0)
35
36#define AR71XX_SPI_IOC_DO BIT(0)
37#define AR71XX_SPI_IOC_CLK BIT(8)
38#define AR71XX_SPI_IOC_CS(n) BIT(16 + (n))
39
40struct ath79_spi {
41 struct spi_bitbang bitbang;
42 u32 ioc_base;
43 u32 reg_ctrl;
44 void __iomem *base;
45 struct clk *clk;
46 unsigned int rrw_delay;
47};
48
49static inline u32 ath79_spi_rr(struct ath79_spi *sp, unsigned int reg)
50{
51 return ioread32(sp->base + reg);
52}
53
54static inline void ath79_spi_wr(struct ath79_spi *sp, unsigned int reg, u32 val)
55{
56 iowrite32(val, sp->base + reg);
57}
58
59static inline struct ath79_spi *ath79_spidev_to_sp(struct spi_device *spi)
60{
61 return spi_master_get_devdata(spi->master);
62}
63
64static inline void ath79_spi_delay(struct ath79_spi *sp, unsigned int nsecs)
65{
66 if (nsecs > sp->rrw_delay)
67 ndelay(nsecs - sp->rrw_delay);
68}
69
70static void ath79_spi_chipselect(struct spi_device *spi, int is_active)
71{
72 struct ath79_spi *sp = ath79_spidev_to_sp(spi);
73 int cs_high = (spi->mode & SPI_CS_HIGH) ? is_active : !is_active;
74 u32 cs_bit = AR71XX_SPI_IOC_CS(spi->chip_select);
75
76 if (cs_high)
77 sp->ioc_base |= cs_bit;
78 else
79 sp->ioc_base &= ~cs_bit;
80
81 ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
82}
83
84static void ath79_spi_enable(struct ath79_spi *sp)
85{
86
87 ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO);
88
89
90 sp->reg_ctrl = ath79_spi_rr(sp, AR71XX_SPI_REG_CTRL);
91 sp->ioc_base = ath79_spi_rr(sp, AR71XX_SPI_REG_IOC);
92
93
94 sp->ioc_base &= ~(AR71XX_SPI_IOC_DO | AR71XX_SPI_IOC_CLK);
95
96
97 ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43);
98}
99
100static void ath79_spi_disable(struct ath79_spi *sp)
101{
102
103 ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl);
104
105 ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
106}
107
108static u32 ath79_spi_txrx_mode0(struct spi_device *spi, unsigned int nsecs,
109 u32 word, u8 bits, unsigned flags)
110{
111 struct ath79_spi *sp = ath79_spidev_to_sp(spi);
112 u32 ioc = sp->ioc_base;
113
114
115 for (word <<= (32 - bits); likely(bits); bits--) {
116 u32 out;
117
118 if (word & (1 << 31))
119 out = ioc | AR71XX_SPI_IOC_DO;
120 else
121 out = ioc & ~AR71XX_SPI_IOC_DO;
122
123
124 ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
125 ath79_spi_delay(sp, nsecs);
126 ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK);
127 ath79_spi_delay(sp, nsecs);
128 if (bits == 1)
129 ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
130
131 word <<= 1;
132 }
133
134 return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);
135}
136
137static int ath79_spi_probe(struct platform_device *pdev)
138{
139 struct spi_master *master;
140 struct ath79_spi *sp;
141 struct ath79_spi_platform_data *pdata;
142 unsigned long rate;
143 int ret;
144
145 master = spi_alloc_master(&pdev->dev, sizeof(*sp));
146 if (master == NULL) {
147 dev_err(&pdev->dev, "failed to allocate spi master\n");
148 return -ENOMEM;
149 }
150
151 sp = spi_master_get_devdata(master);
152 master->dev.of_node = pdev->dev.of_node;
153 platform_set_drvdata(pdev, sp);
154
155 pdata = dev_get_platdata(&pdev->dev);
156
157 master->use_gpio_descriptors = true;
158 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
159 master->setup = spi_bitbang_setup;
160 master->cleanup = spi_bitbang_cleanup;
161 if (pdata) {
162 master->bus_num = pdata->bus_num;
163 master->num_chipselect = pdata->num_chipselect;
164 }
165
166 sp->bitbang.master = master;
167 sp->bitbang.chipselect = ath79_spi_chipselect;
168 sp->bitbang.txrx_word[SPI_MODE_0] = ath79_spi_txrx_mode0;
169 sp->bitbang.flags = SPI_CS_HIGH;
170
171 sp->base = devm_platform_ioremap_resource(pdev, 0);
172 if (IS_ERR(sp->base)) {
173 ret = PTR_ERR(sp->base);
174 goto err_put_master;
175 }
176
177 sp->clk = devm_clk_get(&pdev->dev, "ahb");
178 if (IS_ERR(sp->clk)) {
179 ret = PTR_ERR(sp->clk);
180 goto err_put_master;
181 }
182
183 ret = clk_prepare_enable(sp->clk);
184 if (ret)
185 goto err_put_master;
186
187 rate = DIV_ROUND_UP(clk_get_rate(sp->clk), MHZ);
188 if (!rate) {
189 ret = -EINVAL;
190 goto err_clk_disable;
191 }
192
193 sp->rrw_delay = ATH79_SPI_RRW_DELAY_FACTOR / rate;
194 dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n",
195 sp->rrw_delay);
196
197 ath79_spi_enable(sp);
198 ret = spi_bitbang_start(&sp->bitbang);
199 if (ret)
200 goto err_disable;
201
202 return 0;
203
204err_disable:
205 ath79_spi_disable(sp);
206err_clk_disable:
207 clk_disable_unprepare(sp->clk);
208err_put_master:
209 spi_master_put(sp->bitbang.master);
210
211 return ret;
212}
213
214static int ath79_spi_remove(struct platform_device *pdev)
215{
216 struct ath79_spi *sp = platform_get_drvdata(pdev);
217
218 spi_bitbang_stop(&sp->bitbang);
219 ath79_spi_disable(sp);
220 clk_disable_unprepare(sp->clk);
221 spi_master_put(sp->bitbang.master);
222
223 return 0;
224}
225
226static void ath79_spi_shutdown(struct platform_device *pdev)
227{
228 ath79_spi_remove(pdev);
229}
230
231static const struct of_device_id ath79_spi_of_match[] = {
232 { .compatible = "qca,ar7100-spi", },
233 { },
234};
235MODULE_DEVICE_TABLE(of, ath79_spi_of_match);
236
237static struct platform_driver ath79_spi_driver = {
238 .probe = ath79_spi_probe,
239 .remove = ath79_spi_remove,
240 .shutdown = ath79_spi_shutdown,
241 .driver = {
242 .name = DRV_NAME,
243 .of_match_table = ath79_spi_of_match,
244 },
245};
246module_platform_driver(ath79_spi_driver);
247
248MODULE_DESCRIPTION("SPI controller driver for Atheros AR71XX/AR724X/AR913X");
249MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
250MODULE_LICENSE("GPL v2");
251MODULE_ALIAS("platform:" DRV_NAME);
252
