1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // CS42L43 SPI Controller Driver
4 //
5 // Copyright (C) 2022-2023 Cirrus Logic, Inc. and
6 // Cirrus Logic International Semiconductor Ltd.
7
8 #include <linux/bits.h>
9 #include <linux/bitfield.h>
10 #include <linux/device.h>
11 #include <linux/errno.h>
12 #include <linux/mfd/cs42l43.h>
13 #include <linux/mfd/cs42l43-regs.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/regmap.h>
18 #include <linux/spi/spi.h>
19 #include <linux/units.h>
20
21 #define CS42L43_FIFO_SIZE 16
22 #define CS42L43_SPI_ROOT_HZ (40 * HZ_PER_MHZ)
23 #define CS42L43_SPI_MAX_LENGTH 65532
24
25 enum cs42l43_spi_cmd {
26 CS42L43_WRITE,
27 CS42L43_READ
28 };
29
30 struct cs42l43_spi {
31 struct device *dev;
32 struct regmap *regmap;
33 struct spi_controller *ctlr;
34 };
35
36 static const unsigned int cs42l43_clock_divs[] = {
37 2, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
38 };
39
cs42l43_spi_tx(struct regmap * regmap,const u8 * buf,unsigned int len)40 static int cs42l43_spi_tx(struct regmap *regmap, const u8 *buf, unsigned int len)
41 {
42 const u8 *end = buf + len;
43 u32 val = 0;
44 int ret;
45
46 while (buf < end) {
47 const u8 *block = min(buf + CS42L43_FIFO_SIZE, end);
48
49 while (buf < block) {
50 const u8 *word = min(buf + sizeof(u32), block);
51 int pad = (buf + sizeof(u32)) - word;
52
53 while (buf < word) {
54 val >>= BITS_PER_BYTE;
55 val |= FIELD_PREP(GENMASK(31, 24), *buf);
56
57 buf++;
58 }
59
60 val >>= pad * BITS_PER_BYTE;
61
62 regmap_write(regmap, CS42L43_TX_DATA, val);
63 }
64
65 regmap_write(regmap, CS42L43_TRAN_CONFIG8, CS42L43_SPI_TX_DONE_MASK);
66
67 ret = regmap_read_poll_timeout(regmap, CS42L43_TRAN_STATUS1,
68 val, (val & CS42L43_SPI_TX_REQUEST_MASK),
69 1000, 5000);
70 if (ret)
71 return ret;
72 }
73
74 return 0;
75 }
76
cs42l43_spi_rx(struct regmap * regmap,u8 * buf,unsigned int len)77 static int cs42l43_spi_rx(struct regmap *regmap, u8 *buf, unsigned int len)
78 {
79 u8 *end = buf + len;
80 u32 val;
81 int ret;
82
83 while (buf < end) {
84 u8 *block = min(buf + CS42L43_FIFO_SIZE, end);
85
86 ret = regmap_read_poll_timeout(regmap, CS42L43_TRAN_STATUS1,
87 val, (val & CS42L43_SPI_RX_REQUEST_MASK),
88 1000, 5000);
89 if (ret)
90 return ret;
91
92 while (buf < block) {
93 u8 *word = min(buf + sizeof(u32), block);
94
95 ret = regmap_read(regmap, CS42L43_RX_DATA, &val);
96 if (ret)
97 return ret;
98
99 while (buf < word) {
100 *buf = FIELD_GET(GENMASK(7, 0), val);
101
102 val >>= BITS_PER_BYTE;
103 buf++;
104 }
105 }
106
107 regmap_write(regmap, CS42L43_TRAN_CONFIG8, CS42L43_SPI_RX_DONE_MASK);
108 }
109
110 return 0;
111 }
112
cs42l43_transfer_one(struct spi_controller * ctlr,struct spi_device * spi,struct spi_transfer * tfr)113 static int cs42l43_transfer_one(struct spi_controller *ctlr, struct spi_device *spi,
114 struct spi_transfer *tfr)
115 {
116 struct cs42l43_spi *priv = spi_controller_get_devdata(spi->controller);
117 int i, ret = -EINVAL;
118
119 for (i = 0; i < ARRAY_SIZE(cs42l43_clock_divs); i++) {
120 if (CS42L43_SPI_ROOT_HZ / cs42l43_clock_divs[i] <= tfr->speed_hz)
121 break;
122 }
123
124 if (i == ARRAY_SIZE(cs42l43_clock_divs))
125 return -EINVAL;
126
127 regmap_write(priv->regmap, CS42L43_SPI_CLK_CONFIG1, i);
128
129 if (tfr->tx_buf) {
130 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG3, CS42L43_WRITE);
131 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG4, tfr->len - 1);
132 } else if (tfr->rx_buf) {
133 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG3, CS42L43_READ);
134 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG5, tfr->len - 1);
135 }
136
137 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG1, CS42L43_SPI_START_MASK);
138
139 if (tfr->tx_buf)
140 ret = cs42l43_spi_tx(priv->regmap, (const u8 *)tfr->tx_buf, tfr->len);
141 else if (tfr->rx_buf)
142 ret = cs42l43_spi_rx(priv->regmap, (u8 *)tfr->rx_buf, tfr->len);
143
144 return ret;
145 }
146
cs42l43_set_cs(struct spi_device * spi,bool is_high)147 static void cs42l43_set_cs(struct spi_device *spi, bool is_high)
148 {
149 struct cs42l43_spi *priv = spi_controller_get_devdata(spi->controller);
150
151 if (spi_get_chipselect(spi, 0) == 0)
152 regmap_write(priv->regmap, CS42L43_SPI_CONFIG2, !is_high);
153 }
154
cs42l43_prepare_message(struct spi_controller * ctlr,struct spi_message * msg)155 static int cs42l43_prepare_message(struct spi_controller *ctlr, struct spi_message *msg)
156 {
157 struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
158 struct spi_device *spi = msg->spi;
159 unsigned int spi_config1 = 0;
160
161 /* select another internal CS, which doesn't exist, so CS 0 is not used */
162 if (spi_get_csgpiod(spi, 0))
163 spi_config1 |= 1 << CS42L43_SPI_SS_SEL_SHIFT;
164 if (spi->mode & SPI_CPOL)
165 spi_config1 |= CS42L43_SPI_CPOL_MASK;
166 if (spi->mode & SPI_CPHA)
167 spi_config1 |= CS42L43_SPI_CPHA_MASK;
168 if (spi->mode & SPI_3WIRE)
169 spi_config1 |= CS42L43_SPI_THREE_WIRE_MASK;
170
171 regmap_write(priv->regmap, CS42L43_SPI_CONFIG1, spi_config1);
172
173 return 0;
174 }
175
cs42l43_prepare_transfer_hardware(struct spi_controller * ctlr)176 static int cs42l43_prepare_transfer_hardware(struct spi_controller *ctlr)
177 {
178 struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
179 int ret;
180
181 ret = regmap_write(priv->regmap, CS42L43_BLOCK_EN2, CS42L43_SPI_MSTR_EN_MASK);
182 if (ret)
183 dev_err(priv->dev, "Failed to enable SPI controller: %d\n", ret);
184
185 return ret;
186 }
187
cs42l43_unprepare_transfer_hardware(struct spi_controller * ctlr)188 static int cs42l43_unprepare_transfer_hardware(struct spi_controller *ctlr)
189 {
190 struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
191 int ret;
192
193 ret = regmap_write(priv->regmap, CS42L43_BLOCK_EN2, 0);
194 if (ret)
195 dev_err(priv->dev, "Failed to disable SPI controller: %d\n", ret);
196
197 return ret;
198 }
199
cs42l43_spi_max_length(struct spi_device * spi)200 static size_t cs42l43_spi_max_length(struct spi_device *spi)
201 {
202 return CS42L43_SPI_MAX_LENGTH;
203 }
204
cs42l43_spi_probe(struct platform_device * pdev)205 static int cs42l43_spi_probe(struct platform_device *pdev)
206 {
207 struct cs42l43 *cs42l43 = dev_get_drvdata(pdev->dev.parent);
208 struct cs42l43_spi *priv;
209 struct fwnode_handle *fwnode = dev_fwnode(cs42l43->dev);
210 int ret;
211
212 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
213 if (!priv)
214 return -ENOMEM;
215
216 priv->ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*priv->ctlr));
217 if (!priv->ctlr)
218 return -ENOMEM;
219
220 spi_controller_set_devdata(priv->ctlr, priv);
221
222 priv->dev = &pdev->dev;
223 priv->regmap = cs42l43->regmap;
224
225 priv->ctlr->prepare_message = cs42l43_prepare_message;
226 priv->ctlr->prepare_transfer_hardware = cs42l43_prepare_transfer_hardware;
227 priv->ctlr->unprepare_transfer_hardware = cs42l43_unprepare_transfer_hardware;
228 priv->ctlr->transfer_one = cs42l43_transfer_one;
229 priv->ctlr->set_cs = cs42l43_set_cs;
230 priv->ctlr->max_transfer_size = cs42l43_spi_max_length;
231
232 if (is_of_node(fwnode))
233 fwnode = fwnode_get_named_child_node(fwnode, "spi");
234
235 device_set_node(&priv->ctlr->dev, fwnode);
236
237 priv->ctlr->mode_bits = SPI_3WIRE | SPI_MODE_X_MASK;
238 priv->ctlr->flags = SPI_CONTROLLER_HALF_DUPLEX;
239 priv->ctlr->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16) |
240 SPI_BPW_MASK(32);
241 priv->ctlr->min_speed_hz = CS42L43_SPI_ROOT_HZ /
242 cs42l43_clock_divs[ARRAY_SIZE(cs42l43_clock_divs) - 1];
243 priv->ctlr->max_speed_hz = CS42L43_SPI_ROOT_HZ / cs42l43_clock_divs[0];
244 priv->ctlr->use_gpio_descriptors = true;
245 priv->ctlr->auto_runtime_pm = true;
246
247 devm_pm_runtime_enable(priv->dev);
248 pm_runtime_idle(priv->dev);
249
250 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG6, CS42L43_FIFO_SIZE - 1);
251 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG7, CS42L43_FIFO_SIZE - 1);
252
253 // Disable Watchdog timer and enable stall
254 regmap_write(priv->regmap, CS42L43_SPI_CONFIG3, 0);
255 regmap_write(priv->regmap, CS42L43_SPI_CONFIG4, CS42L43_SPI_STALL_ENA_MASK);
256
257 ret = devm_spi_register_controller(priv->dev, priv->ctlr);
258 if (ret) {
259 dev_err(priv->dev, "Failed to register SPI controller: %d\n", ret);
260 }
261
262 return ret;
263 }
264
265 static const struct platform_device_id cs42l43_spi_id_table[] = {
266 { "cs42l43-spi", },
267 {}
268 };
269 MODULE_DEVICE_TABLE(platform, cs42l43_spi_id_table);
270
271 static struct platform_driver cs42l43_spi_driver = {
272 .driver = {
273 .name = "cs42l43-spi",
274 },
275 .probe = cs42l43_spi_probe,
276 .id_table = cs42l43_spi_id_table,
277 };
278 module_platform_driver(cs42l43_spi_driver);
279
280 MODULE_DESCRIPTION("CS42L43 SPI Driver");
281 MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
282 MODULE_AUTHOR("Maciej Strozek <mstrozek@opensource.cirrus.com>");
283 MODULE_LICENSE("GPL");
284
