1/*
  2 * Copyright 2009-2010 Pengutronix
  3 * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
  4 *
  5 * loosely based on an earlier driver that has
  6 * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
  7 *
  8 * This program is free software; you can redistribute it and/or modify it under
  9 * the terms of the GNU General Public License version 2 as published by the
 10 * Free Software Foundation.
 11 */
 12
 13#include <linux/slab.h>
 14#include <linux/module.h>
 15#include <linux/platform_device.h>
 16#include <linux/interrupt.h>
 17#include <linux/mfd/core.h>
 18#include <linux/mfd/mc13xxx.h>
 19#include <linux/of.h>
 20#include <linux/of_device.h>
 21#include <linux/of_gpio.h>
 22#include <linux/err.h>
 23#include <linux/spi/spi.h>
 24
 25#include "mc13xxx.h"
 26
 27static const struct spi_device_id mc13xxx_device_id[] = {
 28	{
 29		.name = "mc13783",
 30		.driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783,
 31	}, {
 32		.name = "mc13892",
 33		.driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
 34	}, {
 35		.name = "mc34708",
 36		.driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
 37	}, {
 38		/* sentinel */
 39	}
 40};
 41MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
 42
 43static const struct of_device_id mc13xxx_dt_ids[] = {
 44	{ .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
 45	{ .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
 46	{ .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
 47	{ /* sentinel */ }
 48};
 49MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
 50
 51static const struct regmap_config mc13xxx_regmap_spi_config = {
 52	.reg_bits = 7,
 53	.pad_bits = 1,
 54	.val_bits = 24,
 55	.write_flag_mask = 0x80,
 56
 57	.max_register = MC13XXX_NUMREGS,
 58
 59	.cache_type = REGCACHE_NONE,
 60	.use_single_rw = 1,
 61};
 62
 63static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
 64				void *val, size_t val_size)
 65{
 66	unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
 67	unsigned char r[4];
 68	unsigned char *p = val;
 69	struct device *dev = context;
 70	struct spi_device *spi = to_spi_device(dev);
 71	struct spi_transfer t = {
 72		.tx_buf = w,
 73		.rx_buf = r,
 74		.len = 4,
 75	};
 76
 77	struct spi_message m;
 78	int ret;
 79
 80	if (val_size != 3 || reg_size != 1)
 81		return -ENOTSUPP;
 82
 83	spi_message_init(&m);
 84	spi_message_add_tail(&t, &m);
 85	ret = spi_sync(spi, &m);
 86
 87	memcpy(p, &r[1], 3);
 88
 89	return ret;
 90}
 91
 92static int mc13xxx_spi_write(void *context, const void *data, size_t count)
 93{
 94	struct device *dev = context;
 95	struct spi_device *spi = to_spi_device(dev);
 96	const char *reg = data;
 97
 98	if (count != 4)
 99		return -ENOTSUPP;
100
101	/* include errata fix for spi audio problems */
102	if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
103		spi_write(spi, data, count);
104
105	return spi_write(spi, data, count);
106}
107
108/*
109 * We cannot use regmap-spi generic bus implementation here.
110 * The MC13783 chip will get corrupted if CS signal is deasserted
111 * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
112 * has the following errata (DSPhl22960):
113 * "The CSPI negates SS when the FIFO becomes empty with
114 * SSCTL= 0. Software cannot guarantee that the FIFO will not
115 * drain because of higher priority interrupts and the
116 * non-realtime characteristics of the operating system. As a
117 * result, the SS will negate before all of the data has been
118 * transferred to/from the peripheral."
119 * We workaround this by accessing the SPI controller with a
120 * single transfert.
121 */
122
123static struct regmap_bus regmap_mc13xxx_bus = {
124	.write = mc13xxx_spi_write,
125	.read = mc13xxx_spi_read,
126};
127
128static int mc13xxx_spi_probe(struct spi_device *spi)
129{
130	struct mc13xxx *mc13xxx;
131	int ret;
132
133	mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
134	if (!mc13xxx)
135		return -ENOMEM;
136
137	dev_set_drvdata(&spi->dev, mc13xxx);
138
139	spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
140
141	mc13xxx->irq = spi->irq;
142
143	spi->max_speed_hz = spi->max_speed_hz ? : 26000000;
144	ret = spi_setup(spi);
145	if (ret)
146		return ret;
147
148	mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
149					   &spi->dev,
150					   &mc13xxx_regmap_spi_config);
151	if (IS_ERR(mc13xxx->regmap)) {
152		ret = PTR_ERR(mc13xxx->regmap);
153		dev_err(&spi->dev, "Failed to initialize regmap: %d\n", ret);
154		return ret;
155	}
156
157	if (spi->dev.of_node) {
158		const struct of_device_id *of_id =
159			of_match_device(mc13xxx_dt_ids, &spi->dev);
160
161		mc13xxx->variant = of_id->data;
162	} else {
163		const struct spi_device_id *id_entry = spi_get_device_id(spi);
164
165		mc13xxx->variant = (void *)id_entry->driver_data;
166	}
167
168	return mc13xxx_common_init(&spi->dev);
169}
170
171static int mc13xxx_spi_remove(struct spi_device *spi)
172{
173	return mc13xxx_common_exit(&spi->dev);
174}
175
176static struct spi_driver mc13xxx_spi_driver = {
177	.id_table = mc13xxx_device_id,
178	.driver = {
179		.name = "mc13xxx",
180		.of_match_table = mc13xxx_dt_ids,
181	},
182	.probe = mc13xxx_spi_probe,
183	.remove = mc13xxx_spi_remove,
184};
185
186static int __init mc13xxx_init(void)
187{
188	return spi_register_driver(&mc13xxx_spi_driver);
189}
190subsys_initcall(mc13xxx_init);
191
192static void __exit mc13xxx_exit(void)
193{
194	spi_unregister_driver(&mc13xxx_spi_driver);
195}
196module_exit(mc13xxx_exit);
197
198MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
199MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
200MODULE_LICENSE("GPL v2");