1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2009-2010 Pengutronix
4  * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
5  *
6  * loosely based on an earlier driver that has
7  * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
8  */
9 
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/interrupt.h>
14 #include <linux/mfd/core.h>
15 #include <linux/mfd/mc13xxx.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/of_gpio.h>
19 #include <linux/err.h>
20 #include <linux/spi/spi.h>
21 
22 #include "mc13xxx.h"
23 
24 static const struct spi_device_id mc13xxx_device_id[] = {
25 	{
26 		.name = "mc13783",
27 		.driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783,
28 	}, {
29 		.name = "mc13892",
30 		.driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
31 	}, {
32 		.name = "mc34708",
33 		.driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
34 	}, {
35 		/* sentinel */
36 	}
37 };
38 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
39 
40 static const struct of_device_id mc13xxx_dt_ids[] = {
41 	{ .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
42 	{ .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
43 	{ .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
44 	{ /* sentinel */ }
45 };
46 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
47 
48 static const struct regmap_config mc13xxx_regmap_spi_config = {
49 	.reg_bits = 7,
50 	.pad_bits = 1,
51 	.val_bits = 24,
52 	.write_flag_mask = 0x80,
53 
54 	.max_register = MC13XXX_NUMREGS,
55 
56 	.cache_type = REGCACHE_NONE,
57 	.use_single_read = true,
58 	.use_single_write = true,
59 };
60 
mc13xxx_spi_read(void * context,const void * reg,size_t reg_size,void * val,size_t val_size)61 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
62 				void *val, size_t val_size)
63 {
64 	unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
65 	unsigned char r[4];
66 	unsigned char *p = val;
67 	struct device *dev = context;
68 	struct spi_device *spi = to_spi_device(dev);
69 	struct spi_transfer t = {
70 		.tx_buf = w,
71 		.rx_buf = r,
72 		.len = 4,
73 	};
74 
75 	struct spi_message m;
76 	int ret;
77 
78 	if (val_size != 3 || reg_size != 1)
79 		return -ENOTSUPP;
80 
81 	spi_message_init(&m);
82 	spi_message_add_tail(&t, &m);
83 	ret = spi_sync(spi, &m);
84 
85 	memcpy(p, &r[1], 3);
86 
87 	return ret;
88 }
89 
mc13xxx_spi_write(void * context,const void * data,size_t count)90 static int mc13xxx_spi_write(void *context, const void *data, size_t count)
91 {
92 	struct device *dev = context;
93 	struct spi_device *spi = to_spi_device(dev);
94 	const char *reg = data;
95 
96 	if (count != 4)
97 		return -ENOTSUPP;
98 
99 	/* include errata fix for spi audio problems */
100 	if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
101 		spi_write(spi, data, count);
102 
103 	return spi_write(spi, data, count);
104 }
105 
106 /*
107  * We cannot use regmap-spi generic bus implementation here.
108  * The MC13783 chip will get corrupted if CS signal is deasserted
109  * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
110  * has the following errata (DSPhl22960):
111  * "The CSPI negates SS when the FIFO becomes empty with
112  * SSCTL= 0. Software cannot guarantee that the FIFO will not
113  * drain because of higher priority interrupts and the
114  * non-realtime characteristics of the operating system. As a
115  * result, the SS will negate before all of the data has been
116  * transferred to/from the peripheral."
117  * We workaround this by accessing the SPI controller with a
118  * single transfert.
119  */
120 
121 static struct regmap_bus regmap_mc13xxx_bus = {
122 	.write = mc13xxx_spi_write,
123 	.read = mc13xxx_spi_read,
124 };
125 
mc13xxx_spi_probe(struct spi_device * spi)126 static int mc13xxx_spi_probe(struct spi_device *spi)
127 {
128 	struct mc13xxx *mc13xxx;
129 	int ret;
130 
131 	mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
132 	if (!mc13xxx)
133 		return -ENOMEM;
134 
135 	dev_set_drvdata(&spi->dev, mc13xxx);
136 
137 	spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
138 
139 	mc13xxx->irq = spi->irq;
140 
141 	spi->max_speed_hz = spi->max_speed_hz ? : 26000000;
142 	ret = spi_setup(spi);
143 	if (ret)
144 		return ret;
145 
146 	mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
147 					   &spi->dev,
148 					   &mc13xxx_regmap_spi_config);
149 	if (IS_ERR(mc13xxx->regmap)) {
150 		ret = PTR_ERR(mc13xxx->regmap);
151 		dev_err(&spi->dev, "Failed to initialize regmap: %d\n", ret);
152 		return ret;
153 	}
154 
155 	if (spi->dev.of_node) {
156 		const struct of_device_id *of_id =
157 			of_match_device(mc13xxx_dt_ids, &spi->dev);
158 
159 		mc13xxx->variant = of_id->data;
160 	} else {
161 		const struct spi_device_id *id_entry = spi_get_device_id(spi);
162 
163 		mc13xxx->variant = (void *)id_entry->driver_data;
164 	}
165 
166 	return mc13xxx_common_init(&spi->dev);
167 }
168 
mc13xxx_spi_remove(struct spi_device * spi)169 static int mc13xxx_spi_remove(struct spi_device *spi)
170 {
171 	mc13xxx_common_exit(&spi->dev);
172 	return 0;
173 }
174 
175 static struct spi_driver mc13xxx_spi_driver = {
176 	.id_table = mc13xxx_device_id,
177 	.driver = {
178 		.name = "mc13xxx",
179 		.of_match_table = mc13xxx_dt_ids,
180 	},
181 	.probe = mc13xxx_spi_probe,
182 	.remove = mc13xxx_spi_remove,
183 };
184 
mc13xxx_init(void)185 static int __init mc13xxx_init(void)
186 {
187 	return spi_register_driver(&mc13xxx_spi_driver);
188 }
189 subsys_initcall(mc13xxx_init);
190 
mc13xxx_exit(void)191 static void __exit mc13xxx_exit(void)
192 {
193 	spi_unregister_driver(&mc13xxx_spi_driver);
194 }
195 module_exit(mc13xxx_exit);
196 
197 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
198 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
199 MODULE_LICENSE("GPL v2");
200