[PATCH 2/3] mfd: add U8500 STw4500 SPI device support
Mark Brown
broonie at sirena.org.uk
Tue Sep 22 18:01:44 EDT 2009
On Tue, Sep 22, 2009 at 04:07:10AM +0530, srinidhi kasagar wrote:
> From: srinidhi kasagar <srinidhi.kasagar at stericsson.com>
>
> This adds core driver support for STw4500 mixed signal
> multimedia & power management chip. This connects to U8500
MFD patches should be sent to Samuel Ortiz (added to the CCs here).
> on the SSP (pl022) bus operating in SPI protocol and exports
> read/write functions for the device to get access to this chip.
I guess this would work with any SPI controller, though obviously it'd
be rare to find other configurations?
> Signed-off-by: srinidhi kasagar <srinidhi.kasagar at stericsson.com>
> ---
> drivers/mfd/Kconfig | 10 ++++
> drivers/mfd/Makefile | 1 +
> drivers/mfd/stw4500.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 148 insertions(+), 0 deletions(-)
> create mode 100755 drivers/mfd/stw4500.c
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 491ac0f..e3aec52 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -256,6 +256,16 @@ config AB3100_CORE
> LEDs, vibrator, system power and temperature, power management
> and ALSA sound.
>
> +config U8500_STW4500
> + tristate "ST-Ericsson U8500 Mixed Signal Power management chip"
> + depends on SPI
> + default y if ARCH_U8500
> + help
> + Select this option to enable access to STw4500 power management
> + chip. This connects to U8500 on the SSP/SPI bus and exports
> + read/write functions for the devices to get access to this chip.
> + This chip embeds various other multimedia funtionalities as well.
> +
> config EZX_PCAP
> bool "PCAP Support"
> depends on GENERIC_HARDIRQS && SPI_MASTER
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 6f8a9a1..9b15e52 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -44,3 +44,4 @@ obj-$(CONFIG_MFD_PCF50633) += pcf50633-core.o
> obj-$(CONFIG_PCF50633_ADC) += pcf50633-adc.o
> obj-$(CONFIG_PCF50633_GPIO) += pcf50633-gpio.o
> obj-$(CONFIG_AB3100_CORE) += ab3100-core.o
> +obj-$(CONFIG_U8500_STW4500) += stw4500.o
> diff --git a/drivers/mfd/stw4500.c b/drivers/mfd/stw4500.c
> new file mode 100755
> index 0000000..a8c1d39
> --- /dev/null
> +++ b/drivers/mfd/stw4500.c
> @@ -0,0 +1,137 @@
> +/*
> + * Copyright (C) 2009 ST-Ericsson
> + *
> + * Author: Srinidhi KASAGAR <srinidhi.kasagar at stericsson.com>
> + *
> + * 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.
> + *
> + * STw4500 is a companion power management chip used with U8500. On this
> + * platform, this is interfaced with SSP0 controller which is a ARM
> + * primecell pl022.
> + *
> + * At the moment the module just exports read/write features.
> + * Interrupt management to be added.
> + */
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/spi/spi.h>
> +
> +static struct spi_driver stw4500_driver;
Is there any need to forward declare this?
> +
> +struct stw4500_chip {
> + struct spi_device *spi;
> + unsigned long tx_buf[4];
> + unsigned long rx_buf[4];
> +};
> +
> +struct stw4500_chip *the_stw4500;
This should be static.
> +
> +/*
> + * This funtion writes to any STw4500 registers using SPI protocol &
> + * before it writes it packs the data in the below 24 bit frame format
> + *
> + * *|------------------------------------|
> + * *| 23|22...18|17.......10|9|8|7......0|
> + * *| r/w bank adr data |
> + * * ------------------------------------
> + *
> + * This function shouldn't be called from interrupt context
> + */
> +int stw4500_write(unsigned char block, unsigned long addr,
> + unsigned char data)
> +{
Normally the read and write functions would take the device as an
argument, though I guess it's probably not the end of the world for this
hardware.
> + struct spi_transfer xfer;
> + struct spi_message msg;
> + unsigned long spi_data =
> + block << 18 | addr << 10 | data;
> +
> + the_stw4500->tx_buf[0] = spi_data;
> + the_stw4500->rx_buf[0] = 0;
> +
> + xfer.tx_buf = the_stw4500->tx_buf;
> + xfer.rx_buf = NULL;
> + xfer.len = sizeof(unsigned long);
> +
> + spi_message_init(&msg);
> + spi_message_add_tail(&xfer, &msg);
> +
> + return spi_sync(the_stw4500->spi, &msg);
> +}
> +EXPORT_SYMBOL(stw4500_write);
> +
> +int stw4500_read(unsigned char block, unsigned long addr)
> +{
> + struct spi_transfer xfer;
> + struct spi_message msg;
> + unsigned long spi_data =
> + 1 << 23 | block << 18 | addr << 10;
> +
> + the_stw4500->tx_buf[0] = spi_data;
> + the_stw4500->rx_buf[0] = 0;
> +
> + xfer.tx_buf = the_stw4500->tx_buf;
> + xfer.rx_buf = the_stw4500->rx_buf;
> + xfer.len = sizeof(unsigned long);
> +
> + spi_message_init(&msg);
> + spi_message_add_tail(&xfer, &msg);
> +
> + spi_sync(the_stw4500->spi, &msg);
> +
> + return the_stw4500->rx_buf[0];
> +}
> +EXPORT_SYMBOL(stw4500_read);
> +
> +static int __init stw4500_probe(struct spi_device *spi)
> +{
> + struct stw4500_chip *chip;
> + unsigned char revision;
> +
> + chip = kzalloc(sizeof *chip, GFP_KERNEL);
> + if (!chip)
> + return -ENOMEM;
> +
> + chip->spi = spi;
> + spi_set_drvdata(spi, chip);
> + the_stw4500 = chip;
> +
> + /* read the revision register */
> + revision = stw4500_read(0x10, 0x1080);
> + printk(KERN_INFO "STw4500 PMU Initialized, revision = %x\n", revision);
> +
> + return 0;
> +}
I'd expect this function to register child devices for the STW4500
functionality?
> +
> +static int __devexit stw4500_remove(struct spi_device *spi)
> +{
> + struct stw4500_chip *chip =
> + spi_get_drvdata(spi);
> + kfree(chip);
> +
> + return 0;
> +}
> +
> +static struct spi_driver stw4500_driver = {
> + .driver = {
> + .name = "stw4500",
> + .owner = THIS_MODULE,
> + },
> + .probe = stw4500_probe,
> + .remove = __devexit_p(stw4500_remove)
> +};
> +
> +static int __devinit stw4500_init(void)
> +{
> + return spi_register_driver(&stw4500_driver);
> +}
> +
> +static void __exit stw4500_exit(void)
> +{
> + spi_unregister_driver(&stw4500_driver);
> +}
> +
> +subsys_initcall_sync(stw4500_init);
> --
> 1.6.3.GIT
>
>
>
>
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