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/mutex.h> 17 #include <linux/interrupt.h> 18 #include <linux/mfd/core.h> 19 #include <linux/mfd/mc13xxx.h> 20 #include <linux/of.h> 21 #include <linux/of_device.h> 22 #include <linux/of_gpio.h> 23 #include <linux/err.h> 24 #include <linux/spi/spi.h> 25 26 #include "mc13xxx.h" 27 28 static const struct spi_device_id mc13xxx_device_id[] = { 29 { 30 .name = "mc13783", 31 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783, 32 }, { 33 .name = "mc13892", 34 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892, 35 }, { 36 .name = "mc34708", 37 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708, 38 }, { 39 /* sentinel */ 40 } 41 }; 42 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id); 43 44 static const struct of_device_id mc13xxx_dt_ids[] = { 45 { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, }, 46 { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, }, 47 { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, }, 48 { /* sentinel */ } 49 }; 50 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids); 51 52 static struct regmap_config mc13xxx_regmap_spi_config = { 53 .reg_bits = 7, 54 .pad_bits = 1, 55 .val_bits = 24, 56 .write_flag_mask = 0x80, 57 58 .max_register = MC13XXX_NUMREGS, 59 60 .cache_type = REGCACHE_NONE, 61 .use_single_rw = 1, 62 }; 63 64 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size, 65 void *val, size_t val_size) 66 { 67 unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0}; 68 unsigned char r[4]; 69 unsigned char *p = val; 70 struct device *dev = context; 71 struct spi_device *spi = to_spi_device(dev); 72 struct spi_transfer t = { 73 .tx_buf = w, 74 .rx_buf = r, 75 .len = 4, 76 }; 77 78 struct spi_message m; 79 int ret; 80 81 if (val_size != 3 || reg_size != 1) 82 return -ENOTSUPP; 83 84 spi_message_init(&m); 85 spi_message_add_tail(&t, &m); 86 ret = spi_sync(spi, &m); 87 88 memcpy(p, &r[1], 3); 89 90 return ret; 91 } 92 93 static int mc13xxx_spi_write(void *context, const void *data, size_t count) 94 { 95 struct device *dev = context; 96 struct spi_device *spi = to_spi_device(dev); 97 98 if (count != 4) 99 return -ENOTSUPP; 100 101 return spi_write(spi, data, count); 102 } 103 104 /* 105 * We cannot use regmap-spi generic bus implementation here. 106 * The MC13783 chip will get corrupted if CS signal is deasserted 107 * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller 108 * has the following errata (DSPhl22960): 109 * "The CSPI negates SS when the FIFO becomes empty with 110 * SSCTL= 0. Software cannot guarantee that the FIFO will not 111 * drain because of higher priority interrupts and the 112 * non-realtime characteristics of the operating system. As a 113 * result, the SS will negate before all of the data has been 114 * transferred to/from the peripheral." 115 * We workaround this by accessing the SPI controller with a 116 * single transfert. 117 */ 118 119 static struct regmap_bus regmap_mc13xxx_bus = { 120 .write = mc13xxx_spi_write, 121 .read = mc13xxx_spi_read, 122 }; 123 124 static int mc13xxx_spi_probe(struct spi_device *spi) 125 { 126 struct mc13xxx *mc13xxx; 127 struct mc13xxx_platform_data *pdata = dev_get_platdata(&spi->dev); 128 int ret; 129 130 mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL); 131 if (!mc13xxx) 132 return -ENOMEM; 133 134 spi_set_drvdata(spi, mc13xxx); 135 spi->mode = SPI_MODE_0 | SPI_CS_HIGH; 136 137 mc13xxx->dev = &spi->dev; 138 mutex_init(&mc13xxx->lock); 139 140 mc13xxx->regmap = devm_regmap_init(&spi->dev, ®map_mc13xxx_bus, 141 &spi->dev, 142 &mc13xxx_regmap_spi_config); 143 if (IS_ERR(mc13xxx->regmap)) { 144 ret = PTR_ERR(mc13xxx->regmap); 145 dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n", 146 ret); 147 spi_set_drvdata(spi, NULL); 148 return ret; 149 } 150 151 if (spi->dev.of_node) { 152 const struct of_device_id *of_id = 153 of_match_device(mc13xxx_dt_ids, &spi->dev); 154 155 mc13xxx->variant = of_id->data; 156 } else { 157 const struct spi_device_id *id_entry = spi_get_device_id(spi); 158 159 mc13xxx->variant = (void *)id_entry->driver_data; 160 } 161 162 return mc13xxx_common_init(mc13xxx, pdata, spi->irq); 163 } 164 165 static int mc13xxx_spi_remove(struct spi_device *spi) 166 { 167 struct mc13xxx *mc13xxx = spi_get_drvdata(spi); 168 169 mc13xxx_common_cleanup(mc13xxx); 170 171 return 0; 172 } 173 174 static struct spi_driver mc13xxx_spi_driver = { 175 .id_table = mc13xxx_device_id, 176 .driver = { 177 .name = "mc13xxx", 178 .owner = THIS_MODULE, 179 .of_match_table = mc13xxx_dt_ids, 180 }, 181 .probe = mc13xxx_spi_probe, 182 .remove = mc13xxx_spi_remove, 183 }; 184 185 static int __init mc13xxx_init(void) 186 { 187 return spi_register_driver(&mc13xxx_spi_driver); 188 } 189 subsys_initcall(mc13xxx_init); 190 191 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