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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SuperH HSPI bus driver
4 *
5 * Copyright (C) 2011 Kuninori Morimoto
6 *
7 * Based on spi-sh.c:
8 * Based on pxa2xx_spi.c:
9 * Copyright (C) 2011 Renesas Solutions Corp.
10 * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
11 */
12
13#include <linux/clk.h>
14#include <linux/module.h>
15#include <linux/kernel.h>
16#include <linux/timer.h>
17#include <linux/delay.h>
18#include <linux/list.h>
19#include <linux/interrupt.h>
20#include <linux/platform_device.h>
21#include <linux/pm_runtime.h>
22#include <linux/io.h>
23#include <linux/spi/spi.h>
24#include <linux/spi/sh_hspi.h>
25
26#define SPCR 0x00
27#define SPSR 0x04
28#define SPSCR 0x08
29#define SPTBR 0x0C
30#define SPRBR 0x10
31#define SPCR2 0x14
32
33/* SPSR */
34#define RXFL (1 << 2)
35
36struct hspi_priv {
37 void __iomem *addr;
38 struct spi_controller *ctlr;
39 struct device *dev;
40 struct clk *clk;
41};
42
43/*
44 * basic function
45 */
46static void hspi_write(struct hspi_priv *hspi, int reg, u32 val)
47{
48 iowrite32(val, hspi->addr + reg);
49}
50
51static u32 hspi_read(struct hspi_priv *hspi, int reg)
52{
53 return ioread32(hspi->addr + reg);
54}
55
56static void hspi_bit_set(struct hspi_priv *hspi, int reg, u32 mask, u32 set)
57{
58 u32 val = hspi_read(hspi, reg);
59
60 val &= ~mask;
61 val |= set & mask;
62
63 hspi_write(hspi, reg, val);
64}
65
66/*
67 * transfer function
68 */
69static int hspi_status_check_timeout(struct hspi_priv *hspi, u32 mask, u32 val)
70{
71 int t = 256;
72
73 while (t--) {
74 if ((mask & hspi_read(hspi, SPSR)) == val)
75 return 0;
76
77 udelay(10);
78 }
79
80 dev_err(hspi->dev, "timeout\n");
81 return -ETIMEDOUT;
82}
83
84/*
85 * spi host function
86 */
87
88#define hspi_hw_cs_enable(hspi) hspi_hw_cs_ctrl(hspi, 0)
89#define hspi_hw_cs_disable(hspi) hspi_hw_cs_ctrl(hspi, 1)
90static void hspi_hw_cs_ctrl(struct hspi_priv *hspi, int hi)
91{
92 hspi_bit_set(hspi, SPSCR, (1 << 6), (hi) << 6);
93}
94
95static void hspi_hw_setup(struct hspi_priv *hspi,
96 struct spi_message *msg,
97 struct spi_transfer *t)
98{
99 struct spi_device *spi = msg->spi;
100 struct device *dev = hspi->dev;
101 u32 spcr, idiv_clk;
102 u32 rate, best_rate, min, tmp;
103
104 /*
105 * find best IDIV/CLKCx settings
106 */
107 min = ~0;
108 best_rate = 0;
109 spcr = 0;
110 for (idiv_clk = 0x00; idiv_clk <= 0x3F; idiv_clk++) {
111 rate = clk_get_rate(hspi->clk);
112
113 /* IDIV calculation */
114 if (idiv_clk & (1 << 5))
115 rate /= 128;
116 else
117 rate /= 16;
118
119 /* CLKCx calculation */
120 rate /= (((idiv_clk & 0x1F) + 1) * 2);
121
122 /* save best settings */
123 tmp = abs(t->speed_hz - rate);
124 if (tmp < min) {
125 min = tmp;
126 spcr = idiv_clk;
127 best_rate = rate;
128 }
129 }
130
131 if (spi->mode & SPI_CPHA)
132 spcr |= 1 << 7;
133 if (spi->mode & SPI_CPOL)
134 spcr |= 1 << 6;
135
136 dev_dbg(dev, "speed %d/%d\n", t->speed_hz, best_rate);
137
138 hspi_write(hspi, SPCR, spcr);
139 hspi_write(hspi, SPSR, 0x0);
140 hspi_write(hspi, SPSCR, 0x21); /* master mode / CS control */
141}
142
143static int hspi_transfer_one_message(struct spi_controller *ctlr,
144 struct spi_message *msg)
145{
146 struct hspi_priv *hspi = spi_controller_get_devdata(ctlr);
147 struct spi_transfer *t;
148 u32 tx;
149 u32 rx;
150 int ret, i;
151 unsigned int cs_change;
152 const int nsecs = 50;
153
154 dev_dbg(hspi->dev, "%s\n", __func__);
155
156 cs_change = 1;
157 ret = 0;
158 list_for_each_entry(t, &msg->transfers, transfer_list) {
159
160 if (cs_change) {
161 hspi_hw_setup(hspi, msg, t);
162 hspi_hw_cs_enable(hspi);
163 ndelay(nsecs);
164 }
165 cs_change = t->cs_change;
166
167 for (i = 0; i < t->len; i++) {
168
169 /* wait remains */
170 ret = hspi_status_check_timeout(hspi, 0x1, 0);
171 if (ret < 0)
172 break;
173
174 tx = 0;
175 if (t->tx_buf)
176 tx = (u32)((u8 *)t->tx_buf)[i];
177
178 hspi_write(hspi, SPTBR, tx);
179
180 /* wait receive */
181 ret = hspi_status_check_timeout(hspi, 0x4, 0x4);
182 if (ret < 0)
183 break;
184
185 rx = hspi_read(hspi, SPRBR);
186 if (t->rx_buf)
187 ((u8 *)t->rx_buf)[i] = (u8)rx;
188
189 }
190
191 msg->actual_length += t->len;
192
193 spi_transfer_delay_exec(t);
194
195 if (cs_change) {
196 ndelay(nsecs);
197 hspi_hw_cs_disable(hspi);
198 ndelay(nsecs);
199 }
200 }
201
202 msg->status = ret;
203 if (!cs_change) {
204 ndelay(nsecs);
205 hspi_hw_cs_disable(hspi);
206 }
207 spi_finalize_current_message(ctlr);
208
209 return ret;
210}
211
212static int hspi_probe(struct platform_device *pdev)
213{
214 struct resource *res;
215 struct spi_controller *ctlr;
216 struct hspi_priv *hspi;
217 struct clk *clk;
218 int ret;
219
220 /* get base addr */
221 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
222 if (!res) {
223 dev_err(&pdev->dev, "invalid resource\n");
224 return -EINVAL;
225 }
226
227 ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*hspi));
228 if (!ctlr)
229 return -ENOMEM;
230
231 clk = clk_get(&pdev->dev, NULL);
232 if (IS_ERR(clk)) {
233 dev_err(&pdev->dev, "couldn't get clock\n");
234 return PTR_ERR(clk);
235 }
236
237 hspi = spi_controller_get_devdata(ctlr);
238 platform_set_drvdata(pdev, hspi);
239
240 /* init hspi */
241 hspi->ctlr = ctlr;
242 hspi->dev = &pdev->dev;
243 hspi->clk = clk;
244 hspi->addr = devm_ioremap(hspi->dev,
245 res->start, resource_size(res));
246 if (!hspi->addr) {
247 ret = -ENOMEM;
248 goto error1;
249 }
250
251 pm_runtime_enable(&pdev->dev);
252
253 ctlr->bus_num = pdev->id;
254 ctlr->mode_bits = SPI_CPOL | SPI_CPHA;
255 ctlr->auto_runtime_pm = true;
256 ctlr->transfer_one_message = hspi_transfer_one_message;
257 ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
258
259 ret = spi_register_controller(ctlr);
260 if (ret < 0) {
261 dev_err(&pdev->dev, "failed to register controller\n");
262 goto error2;
263 }
264
265 return 0;
266
267 error2:
268 pm_runtime_disable(&pdev->dev);
269 error1:
270 clk_put(clk);
271
272 return ret;
273}
274
275static void hspi_remove(struct platform_device *pdev)
276{
277 struct hspi_priv *hspi = platform_get_drvdata(pdev);
278
279 spi_unregister_controller(hspi->ctlr);
280
281 pm_runtime_disable(&pdev->dev);
282
283 clk_put(hspi->clk);
284}
285
286static const struct of_device_id hspi_of_match[] = {
287 { .compatible = "renesas,hspi", },
288 { /* sentinel */ }
289};
290MODULE_DEVICE_TABLE(of, hspi_of_match);
291
292static struct platform_driver hspi_driver = {
293 .probe = hspi_probe,
294 .remove = hspi_remove,
295 .driver = {
296 .name = "sh-hspi",
297 .of_match_table = hspi_of_match,
298 },
299};
300module_platform_driver(hspi_driver);
301
302MODULE_DESCRIPTION("SuperH HSPI bus driver");
303MODULE_LICENSE("GPL v2");
304MODULE_AUTHOR("Kuninori Morimoto <[email protected]>");
305MODULE_ALIAS("platform:sh-hspi");