1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * SPI driver for Renesas Synchronization Management Unit (SMU) devices.
  4 *
  5 * Copyright (C) 2021 Integrated Device Technology, Inc., a Renesas Company.
  6 */
  7
  8#include <linux/init.h>
  9#include <linux/kernel.h>
 10#include <linux/mfd/core.h>
 11#include <linux/mfd/rsmu.h>
 12#include <linux/module.h>
 13#include <linux/of.h>
 14#include <linux/regmap.h>
 15#include <linux/slab.h>
 16#include <linux/spi/spi.h>
 17
 18#include "rsmu.h"
 19
 20#define	RSMU_CM_PAGE_ADDR		0x7C
 21#define	RSMU_SABRE_PAGE_ADDR		0x7F
 22#define	RSMU_HIGHER_ADDR_MASK		0xFF80
 23#define	RSMU_HIGHER_ADDR_SHIFT		7
 24#define	RSMU_LOWER_ADDR_MASK		0x7F
 25
 26static int rsmu_read_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
 27{
 28	struct spi_device *client = to_spi_device(rsmu->dev);
 29	struct spi_transfer xfer = {0};
 30	struct spi_message msg;
 31	u8 cmd[256] = {0};
 32	u8 rsp[256] = {0};
 33	int ret;
 34
 35	cmd[0] = reg | 0x80;
 36	xfer.rx_buf = rsp;
 37	xfer.len = bytes + 1;
 38	xfer.tx_buf = cmd;
 39	xfer.bits_per_word = client->bits_per_word;
 40	xfer.speed_hz = client->max_speed_hz;
 41
 42	spi_message_init(&msg);
 43	spi_message_add_tail(&xfer, &msg);
 44
 45	/*
 46	 * 4-wire SPI is a shift register, so for every byte you send,
 47	 * you get one back at the same time. Example read from 0xC024,
 48	 * which has value of 0x2D
 49	 *
 50	 * MOSI:
 51	 *       7C 00 C0 #Set page register
 52	 *       A4 00    #MSB is set, so this is read command
 53	 * MISO:
 54	 *       XX 2D    #XX is a dummy byte from sending A4 and we
 55	 *                 need to throw it away
 56	 */
 57	ret = spi_sync(client, &msg);
 58	if (ret >= 0)
 59		memcpy(buf, &rsp[1], xfer.len-1);
 60
 61	return ret;
 62}
 63
 64static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
 65{
 66	struct spi_device *client = to_spi_device(rsmu->dev);
 67	struct spi_transfer xfer = {0};
 68	struct spi_message msg;
 69	u8 cmd[256] = {0};
 70
 71	cmd[0] = reg;
 72	memcpy(&cmd[1], buf, bytes);
 73
 74	xfer.len = bytes + 1;
 75	xfer.tx_buf = cmd;
 76	xfer.bits_per_word = client->bits_per_word;
 77	xfer.speed_hz = client->max_speed_hz;
 78	spi_message_init(&msg);
 79	spi_message_add_tail(&xfer, &msg);
 80
 81	return  spi_sync(client, &msg);
 82}
 83
 84/*
 85 * 1-byte (1B) offset addressing:
 86 * 16-bit register address: the lower 7 bits of the register address come
 87 * from the offset addr byte and the upper 9 bits come from the page register.
 88 */
 89static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u16 reg)
 90{
 91	u8 page_reg;
 92	u8 buf[2];
 93	u16 bytes;
 94	u16 page;
 95	int err;
 96
 97	switch (rsmu->type) {
 98	case RSMU_CM:
 99		page_reg = RSMU_CM_PAGE_ADDR;
100		page = reg & RSMU_HIGHER_ADDR_MASK;
101		buf[0] = (u8)(page & 0xff);
102		buf[1] = (u8)((page >> 8) & 0xff);
103		bytes = 2;
104		break;
105	case RSMU_SABRE:
106		page_reg = RSMU_SABRE_PAGE_ADDR;
107		page = reg >> RSMU_HIGHER_ADDR_SHIFT;
108		buf[0] = (u8)(page & 0xff);
109		bytes = 1;
110		break;
111	default:
112		dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
113		return -ENODEV;
114	}
115
116	/* Simply return if we are on the same page */
117	if (rsmu->page == page)
118		return 0;
119
120	err = rsmu_write_device(rsmu, page_reg, buf, bytes);
121	if (err)
122		dev_err(rsmu->dev, "Failed to set page offset 0x%x\n", page);
123	else
124		/* Remember the last page */
125		rsmu->page = page;
126
127	return err;
128}
129
130static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val)
131{
132	struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
133	u8 addr = (u8)(reg & RSMU_LOWER_ADDR_MASK);
134	int err;
135
136	err = rsmu_write_page_register(rsmu, reg);
137	if (err)
138		return err;
139
140	err = rsmu_read_device(rsmu, addr, (u8 *)val, 1);
141	if (err)
142		dev_err(rsmu->dev, "Failed to read offset address 0x%x\n", addr);
143
144	return err;
145}
146
147static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val)
148{
149	struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
150	u8 addr = (u8)(reg & RSMU_LOWER_ADDR_MASK);
151	u8 data = (u8)val;
152	int err;
153
154	err = rsmu_write_page_register(rsmu, reg);
155	if (err)
156		return err;
157
158	err = rsmu_write_device(rsmu, addr, &data, 1);
159	if (err)
160		dev_err(rsmu->dev,
161			"Failed to write offset address 0x%x\n", addr);
162
163	return err;
164}
165
166static const struct regmap_config rsmu_cm_regmap_config = {
167	.reg_bits = 16,
168	.val_bits = 8,
169	.max_register = 0xD000,
170	.reg_read = rsmu_reg_read,
171	.reg_write = rsmu_reg_write,
172	.cache_type = REGCACHE_NONE,
173};
174
175static const struct regmap_config rsmu_sabre_regmap_config = {
176	.reg_bits = 16,
177	.val_bits = 8,
178	.max_register = 0x400,
179	.reg_read = rsmu_reg_read,
180	.reg_write = rsmu_reg_write,
181	.cache_type = REGCACHE_NONE,
182};
183
184static int rsmu_spi_probe(struct spi_device *client)
185{
186	const struct spi_device_id *id = spi_get_device_id(client);
187	const struct regmap_config *cfg;
188	struct rsmu_ddata *rsmu;
189	int ret;
190
191	rsmu = devm_kzalloc(&client->dev, sizeof(*rsmu), GFP_KERNEL);
192	if (!rsmu)
193		return -ENOMEM;
194
195	spi_set_drvdata(client, rsmu);
196
197	rsmu->dev = &client->dev;
198	rsmu->type = (enum rsmu_type)id->driver_data;
199
200	/* Initialize regmap */
201	switch (rsmu->type) {
202	case RSMU_CM:
203		cfg = &rsmu_cm_regmap_config;
204		break;
205	case RSMU_SABRE:
206		cfg = &rsmu_sabre_regmap_config;
207		break;
208	default:
209		dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
210		return -ENODEV;
211	}
212
213	rsmu->regmap = devm_regmap_init(&client->dev, NULL, client, cfg);
214	if (IS_ERR(rsmu->regmap)) {
215		ret = PTR_ERR(rsmu->regmap);
216		dev_err(rsmu->dev, "Failed to allocate register map: %d\n", ret);
217		return ret;
218	}
219
220	return rsmu_core_init(rsmu);
221}
222
223static void rsmu_spi_remove(struct spi_device *client)
224{
225	struct rsmu_ddata *rsmu = spi_get_drvdata(client);
226
227	rsmu_core_exit(rsmu);
228}
229
230static const struct spi_device_id rsmu_spi_id[] = {
231	{ "8a34000",  RSMU_CM },
232	{ "8a34001",  RSMU_CM },
233	{ "82p33810", RSMU_SABRE },
234	{ "82p33811", RSMU_SABRE },
235	{}
236};
237MODULE_DEVICE_TABLE(spi, rsmu_spi_id);
238
239static const struct of_device_id rsmu_spi_of_match[] = {
240	{ .compatible = "idt,8a34000",  .data = (void *)RSMU_CM },
241	{ .compatible = "idt,8a34001",  .data = (void *)RSMU_CM },
242	{ .compatible = "idt,82p33810", .data = (void *)RSMU_SABRE },
243	{ .compatible = "idt,82p33811", .data = (void *)RSMU_SABRE },
244	{}
245};
246MODULE_DEVICE_TABLE(of, rsmu_spi_of_match);
247
248static struct spi_driver rsmu_spi_driver = {
249	.driver = {
250		.name = "rsmu-spi",
251		.of_match_table = of_match_ptr(rsmu_spi_of_match),
252	},
253	.probe = rsmu_spi_probe,
254	.remove	= rsmu_spi_remove,
255	.id_table = rsmu_spi_id,
256};
257
258static int __init rsmu_spi_init(void)
259{
260	return spi_register_driver(&rsmu_spi_driver);
261}
262subsys_initcall(rsmu_spi_init);
263
264static void __exit rsmu_spi_exit(void)
265{
266	spi_unregister_driver(&rsmu_spi_driver);
267}
268module_exit(rsmu_spi_exit);
269
270MODULE_DESCRIPTION("Renesas SMU SPI driver");
271MODULE_LICENSE("GPL");