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Linux/drivers/mfd/mc13xxx-spi.c

  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 
 27 static 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 };
 41 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
 42 
 43 static 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 };
 49 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
 50 
 51 static 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 
 63 static 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 
 92 static 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 
123 static struct regmap_bus regmap_mc13xxx_bus = {
124         .write = mc13xxx_spi_write,
125         .read = mc13xxx_spi_read,
126 };
127 
128 static 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 
171 static int mc13xxx_spi_remove(struct spi_device *spi)
172 {
173         return mc13xxx_common_exit(&spi->dev);
174 }
175 
176 static struct spi_driver mc13xxx_spi_driver = {
177         .id_table = mc13xxx_device_id,
178         .driver = {
179                 .name = "mc13xxx",
180                 .owner = THIS_MODULE,
181                 .of_match_table = mc13xxx_dt_ids,
182         },
183         .probe = mc13xxx_spi_probe,
184         .remove = mc13xxx_spi_remove,
185 };
186 
187 static int __init mc13xxx_init(void)
188 {
189         return spi_register_driver(&mc13xxx_spi_driver);
190 }
191 subsys_initcall(mc13xxx_init);
192 
193 static void __exit mc13xxx_exit(void)
194 {
195         spi_unregister_driver(&mc13xxx_spi_driver);
196 }
197 module_exit(mc13xxx_exit);
198 
199 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
200 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
201 MODULE_LICENSE("GPL v2");
202 

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