c0d4010e11
The registers on the AB8500 are only 8 bits wide, so the content of the remaining bits is undefined. Let's mask off the undefined stuff when returning a register in an SPI read. Acked-by: Rabin Vincent <rabin.vincent@stericsson.com> Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
138 lines
3 KiB
C
138 lines
3 KiB
C
/*
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* Copyright (C) ST-Ericsson SA 2010
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*
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* License Terms: GNU General Public License v2
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* Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/spi/spi.h>
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#include <linux/mfd/ab8500.h>
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/*
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* This funtion writes to any AB8500 registers using
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* SPI protocol & before it writes it packs the data
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* in the below 24 bit frame format
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*
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* *|------------------------------------|
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* *| 23|22...18|17.......10|9|8|7......0|
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* *| r/w bank adr data |
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* * ------------------------------------
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*
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* This function shouldn't be called from interrupt
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* context
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*/
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static int ab8500_spi_write(struct ab8500 *ab8500, u16 addr, u8 data)
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{
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struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
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dev);
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unsigned long spi_data = addr << 10 | data;
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struct spi_transfer xfer;
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struct spi_message msg;
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ab8500->tx_buf[0] = spi_data;
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ab8500->rx_buf[0] = 0;
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xfer.tx_buf = ab8500->tx_buf;
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xfer.rx_buf = NULL;
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xfer.len = sizeof(unsigned long);
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spi_message_init(&msg);
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spi_message_add_tail(&xfer, &msg);
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return spi_sync(spi, &msg);
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}
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static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr)
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{
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struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
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dev);
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unsigned long spi_data = 1 << 23 | addr << 10;
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struct spi_transfer xfer;
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struct spi_message msg;
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int ret;
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ab8500->tx_buf[0] = spi_data;
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ab8500->rx_buf[0] = 0;
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xfer.tx_buf = ab8500->tx_buf;
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xfer.rx_buf = ab8500->rx_buf;
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xfer.len = sizeof(unsigned long);
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spi_message_init(&msg);
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spi_message_add_tail(&xfer, &msg);
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ret = spi_sync(spi, &msg);
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if (!ret)
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/*
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* Only the 8 lowermost bytes are
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* defined with value, the rest may
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* vary depending on chip/board noise.
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*/
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ret = ab8500->rx_buf[0] & 0xFFU;
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return ret;
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}
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static int __devinit ab8500_spi_probe(struct spi_device *spi)
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{
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struct ab8500 *ab8500;
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int ret;
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ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL);
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if (!ab8500)
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return -ENOMEM;
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ab8500->dev = &spi->dev;
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ab8500->irq = spi->irq;
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ab8500->read = ab8500_spi_read;
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ab8500->write = ab8500_spi_write;
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spi_set_drvdata(spi, ab8500);
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ret = ab8500_init(ab8500);
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if (ret)
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kfree(ab8500);
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return ret;
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}
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static int __devexit ab8500_spi_remove(struct spi_device *spi)
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{
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struct ab8500 *ab8500 = spi_get_drvdata(spi);
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ab8500_exit(ab8500);
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kfree(ab8500);
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return 0;
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}
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static struct spi_driver ab8500_spi_driver = {
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.driver = {
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.name = "ab8500",
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.owner = THIS_MODULE,
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},
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.probe = ab8500_spi_probe,
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.remove = __devexit_p(ab8500_spi_remove)
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};
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static int __init ab8500_spi_init(void)
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{
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return spi_register_driver(&ab8500_spi_driver);
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}
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subsys_initcall(ab8500_spi_init);
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static void __exit ab8500_spi_exit(void)
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{
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spi_unregister_driver(&ab8500_spi_driver);
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}
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module_exit(ab8500_spi_exit);
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MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com");
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MODULE_DESCRIPTION("AB8500 SPI");
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MODULE_LICENSE("GPL v2");
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