Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git...
[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / spi / spi-xcomm.c
1 /*
2  * Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver
3  *
4  * Copyright 2012 Analog Devices Inc.
5  * Author: Lars-Peter Clausen <lars@metafoo.de>
6  *
7  * Licensed under the GPL-2 or later.
8  */
9
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/delay.h>
14 #include <linux/i2c.h>
15 #include <linux/spi/spi.h>
16 #include <asm/unaligned.h>
17
18 #define SPI_XCOMM_SETTINGS_LEN_OFFSET           10
19 #define SPI_XCOMM_SETTINGS_3WIRE                BIT(6)
20 #define SPI_XCOMM_SETTINGS_CS_HIGH              BIT(5)
21 #define SPI_XCOMM_SETTINGS_SAMPLE_END           BIT(4)
22 #define SPI_XCOMM_SETTINGS_CPHA                 BIT(3)
23 #define SPI_XCOMM_SETTINGS_CPOL                 BIT(2)
24 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK       0x3
25 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_64         0x2
26 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_16         0x1
27 #define SPI_XCOMM_SETTINGS_CLOCK_DIV_4          0x0
28
29 #define SPI_XCOMM_CMD_UPDATE_CONFIG     0x03
30 #define SPI_XCOMM_CMD_WRITE             0x04
31
32 #define SPI_XCOMM_CLOCK 48000000
33
34 struct spi_xcomm {
35         struct i2c_client *i2c;
36
37         uint16_t settings;
38         uint16_t chipselect;
39
40         unsigned int current_speed;
41
42         uint8_t buf[63];
43 };
44
45 static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len)
46 {
47         uint16_t settings;
48         uint8_t *buf = spi_xcomm->buf;
49
50         settings = spi_xcomm->settings;
51         settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET;
52
53         buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG;
54         put_unaligned_be16(settings, &buf[1]);
55         put_unaligned_be16(spi_xcomm->chipselect, &buf[3]);
56
57         return i2c_master_send(spi_xcomm->i2c, buf, 5);
58 }
59
60 static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
61         struct spi_device *spi, int is_active)
62 {
63         unsigned long cs = spi->chip_select;
64         uint16_t chipselect = spi_xcomm->chipselect;
65
66         if (is_active)
67                 chipselect |= BIT(cs);
68         else
69                 chipselect &= ~BIT(cs);
70
71         spi_xcomm->chipselect = chipselect;
72 }
73
74 static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm,
75         struct spi_device *spi, struct spi_transfer *t, unsigned int *settings)
76 {
77         unsigned int speed;
78
79         if (t->len > 62)
80                 return -EINVAL;
81
82         speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
83
84         if (speed != spi_xcomm->current_speed) {
85                 unsigned int divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, speed);
86                 if (divider >= 64)
87                         *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64;
88                 else if (divider >= 16)
89                         *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16;
90                 else
91                         *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4;
92
93                 spi_xcomm->current_speed = speed;
94         }
95
96         if (spi->mode & SPI_CPOL)
97                 *settings |= SPI_XCOMM_SETTINGS_CPOL;
98         else
99                 *settings &= ~SPI_XCOMM_SETTINGS_CPOL;
100
101         if (spi->mode & SPI_CPHA)
102                 *settings &= ~SPI_XCOMM_SETTINGS_CPHA;
103         else
104                 *settings |= SPI_XCOMM_SETTINGS_CPHA;
105
106         if (spi->mode & SPI_3WIRE)
107                 *settings |= SPI_XCOMM_SETTINGS_3WIRE;
108         else
109                 *settings &= ~SPI_XCOMM_SETTINGS_3WIRE;
110
111         return 0;
112 }
113
114 static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm,
115         struct spi_device *spi, struct spi_transfer *t)
116 {
117         int ret;
118
119         if (t->tx_buf) {
120                 spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE;
121                 memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len);
122
123                 ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1);
124                 if (ret < 0)
125                         return ret;
126                 else if (ret != t->len + 1)
127                         return -EIO;
128         } else if (t->rx_buf) {
129                 ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len);
130                 if (ret < 0)
131                         return ret;
132                 else if (ret != t->len)
133                         return -EIO;
134         }
135
136         return t->len;
137 }
138
139 static int spi_xcomm_transfer_one(struct spi_master *master,
140         struct spi_message *msg)
141 {
142         struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master);
143         unsigned int settings = spi_xcomm->settings;
144         struct spi_device *spi = msg->spi;
145         unsigned cs_change = 0;
146         struct spi_transfer *t;
147         bool is_first = true;
148         int status = 0;
149         bool is_last;
150
151         is_first = true;
152
153         spi_xcomm_chipselect(spi_xcomm, spi, true);
154
155         list_for_each_entry(t, &msg->transfers, transfer_list) {
156
157                 if (!t->tx_buf && !t->rx_buf && t->len) {
158                         status = -EINVAL;
159                         break;
160                 }
161
162                 status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings);
163                 if (status < 0)
164                         break;
165
166                 is_last = list_is_last(&t->transfer_list, &msg->transfers);
167                 cs_change = t->cs_change;
168
169                 if (cs_change ^ is_last)
170                         settings |= BIT(5);
171                 else
172                         settings &= ~BIT(5);
173
174                 if (t->rx_buf) {
175                         spi_xcomm->settings = settings;
176                         status = spi_xcomm_sync_config(spi_xcomm, t->len);
177                         if (status < 0)
178                                 break;
179                 } else if (settings != spi_xcomm->settings || is_first) {
180                         spi_xcomm->settings = settings;
181                         status = spi_xcomm_sync_config(spi_xcomm, 0);
182                         if (status < 0)
183                                 break;
184                 }
185
186                 if (t->len) {
187                         status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t);
188
189                         if (status < 0)
190                                 break;
191
192                         if (status > 0)
193                                 msg->actual_length += status;
194                 }
195                 status = 0;
196
197                 if (t->delay_usecs)
198                         udelay(t->delay_usecs);
199
200                 is_first = false;
201         }
202
203         if (status != 0 || !cs_change)
204                 spi_xcomm_chipselect(spi_xcomm, spi, false);
205
206         msg->status = status;
207         spi_finalize_current_message(master);
208
209         return status;
210 }
211
212 static int spi_xcomm_probe(struct i2c_client *i2c,
213         const struct i2c_device_id *id)
214 {
215         struct spi_xcomm *spi_xcomm;
216         struct spi_master *master;
217         int ret;
218
219         master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm));
220         if (!master)
221                 return -ENOMEM;
222
223         spi_xcomm = spi_master_get_devdata(master);
224         spi_xcomm->i2c = i2c;
225
226         master->num_chipselect = 16;
227         master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE;
228         master->bits_per_word_mask = SPI_BPW_MASK(8);
229         master->flags = SPI_MASTER_HALF_DUPLEX;
230         master->transfer_one_message = spi_xcomm_transfer_one;
231         master->dev.of_node = i2c->dev.of_node;
232         i2c_set_clientdata(i2c, master);
233
234         ret = devm_spi_register_master(&i2c->dev, master);
235         if (ret < 0)
236                 spi_master_put(master);
237
238         return ret;
239 }
240
241 static const struct i2c_device_id spi_xcomm_ids[] = {
242         { "spi-xcomm" },
243         { },
244 };
245
246 static struct i2c_driver spi_xcomm_driver = {
247         .driver = {
248                 .name   = "spi-xcomm",
249                 .owner  = THIS_MODULE,
250         },
251         .id_table       = spi_xcomm_ids,
252         .probe          = spi_xcomm_probe,
253 };
254 module_i2c_driver(spi_xcomm_driver);
255
256 MODULE_LICENSE("GPL");
257 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
258 MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");