diff options
Diffstat (limited to 'drivers/mfd/mc13xxx-spi.c')
| -rw-r--r-- | drivers/mfd/mc13xxx-spi.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/drivers/mfd/mc13xxx-spi.c b/drivers/mfd/mc13xxx-spi.c new file mode 100644 index 000000000..58a170e45 --- /dev/null +++ b/drivers/mfd/mc13xxx-spi.c @@ -0,0 +1,201 @@ +/* + * Copyright 2009-2010 Pengutronix + * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> + * + * loosely based on an earlier driver that has + * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de> + * + * This program is free software; you can redistribute it and/or modify it under + * the terms of the GNU General Public License version 2 as published by the + * Free Software Foundation. + */ + +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/mfd/core.h> +#include <linux/mfd/mc13xxx.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_gpio.h> +#include <linux/err.h> +#include <linux/spi/spi.h> + +#include "mc13xxx.h" + +static const struct spi_device_id mc13xxx_device_id[] = { + { + .name = "mc13783", + .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783, + }, { + .name = "mc13892", + .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892, + }, { + .name = "mc34708", + .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708, + }, { + /* sentinel */ + } +}; +MODULE_DEVICE_TABLE(spi, mc13xxx_device_id); + +static const struct of_device_id mc13xxx_dt_ids[] = { + { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, }, + { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, }, + { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids); + +static const struct regmap_config mc13xxx_regmap_spi_config = { + .reg_bits = 7, + .pad_bits = 1, + .val_bits = 24, + .write_flag_mask = 0x80, + + .max_register = MC13XXX_NUMREGS, + + .cache_type = REGCACHE_NONE, + .use_single_rw = 1, +}; + +static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0}; + unsigned char r[4]; + unsigned char *p = val; + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + struct spi_transfer t = { + .tx_buf = w, + .rx_buf = r, + .len = 4, + }; + + struct spi_message m; + int ret; + + if (val_size != 3 || reg_size != 1) + return -ENOTSUPP; + + spi_message_init(&m); + spi_message_add_tail(&t, &m); + ret = spi_sync(spi, &m); + + memcpy(p, &r[1], 3); + + return ret; +} + +static int mc13xxx_spi_write(void *context, const void *data, size_t count) +{ + struct device *dev = context; + struct spi_device *spi = to_spi_device(dev); + const char *reg = data; + + if (count != 4) + return -ENOTSUPP; + + /* include errata fix for spi audio problems */ + if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC) + spi_write(spi, data, count); + + return spi_write(spi, data, count); +} + +/* + * We cannot use regmap-spi generic bus implementation here. + * The MC13783 chip will get corrupted if CS signal is deasserted + * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller + * has the following errata (DSPhl22960): + * "The CSPI negates SS when the FIFO becomes empty with + * SSCTL= 0. Software cannot guarantee that the FIFO will not + * drain because of higher priority interrupts and the + * non-realtime characteristics of the operating system. As a + * result, the SS will negate before all of the data has been + * transferred to/from the peripheral." + * We workaround this by accessing the SPI controller with a + * single transfert. + */ + +static struct regmap_bus regmap_mc13xxx_bus = { + .write = mc13xxx_spi_write, + .read = mc13xxx_spi_read, +}; + +static int mc13xxx_spi_probe(struct spi_device *spi) +{ + struct mc13xxx *mc13xxx; + int ret; + + mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL); + if (!mc13xxx) + return -ENOMEM; + + dev_set_drvdata(&spi->dev, mc13xxx); + + spi->mode = SPI_MODE_0 | SPI_CS_HIGH; + + mc13xxx->irq = spi->irq; + + spi->max_speed_hz = spi->max_speed_hz ? : 26000000; + ret = spi_setup(spi); + if (ret) + return ret; + + mc13xxx->regmap = devm_regmap_init(&spi->dev, ®map_mc13xxx_bus, + &spi->dev, + &mc13xxx_regmap_spi_config); + if (IS_ERR(mc13xxx->regmap)) { + ret = PTR_ERR(mc13xxx->regmap); + dev_err(&spi->dev, "Failed to initialize regmap: %d\n", ret); + return ret; + } + + if (spi->dev.of_node) { + const struct of_device_id *of_id = + of_match_device(mc13xxx_dt_ids, &spi->dev); + + mc13xxx->variant = of_id->data; + } else { + const struct spi_device_id *id_entry = spi_get_device_id(spi); + + mc13xxx->variant = (void *)id_entry->driver_data; + } + + return mc13xxx_common_init(&spi->dev); +} + +static int mc13xxx_spi_remove(struct spi_device *spi) +{ + return mc13xxx_common_exit(&spi->dev); +} + +static struct spi_driver mc13xxx_spi_driver = { + .id_table = mc13xxx_device_id, + .driver = { + .name = "mc13xxx", + .owner = THIS_MODULE, + .of_match_table = mc13xxx_dt_ids, + }, + .probe = mc13xxx_spi_probe, + .remove = mc13xxx_spi_remove, +}; + +static int __init mc13xxx_init(void) +{ + return spi_register_driver(&mc13xxx_spi_driver); +} +subsys_initcall(mc13xxx_init); + +static void __exit mc13xxx_exit(void) +{ + spi_unregister_driver(&mc13xxx_spi_driver); +} +module_exit(mc13xxx_exit); + +MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC"); +MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>"); +MODULE_LICENSE("GPL v2"); |