[PATCH] IBM GPIO driver for PowerPC 4xx is back from the dead

Here is a patch for linux 2.6.18 that makes come back the old ibm gpio
driver from 2.6.10.

It is mainly useful for compatibility with old linux 2.4 from Montavista
I think, because direct memory access seems the new way to go.

Signed-off-by: Jean-Baptiste Maneyrol
[off-list ref]


Jean-Baptiste Maneyrol
Teamlog - France

On Friday 29 September 2006 10:29, Jean-Baptiste Maneyrol wrote:

diff -Naur linux-2.6.18_gpio/drivers/char/ibm_gpio.c tlgate_gpio/drivers/=

char/ibm_gpio.c

=2E000000000 +0100

0200

<insert usual comment about removing the file name from the file>

+ * BRIEF MODULE DESCRIPTION
+ * =A0API for IBM PowerPC 4xx GPIO device.
+ * =A0Driver for IBM PowerPC 4xx GPIO device.
+ *
+ * =A0Armin Kuster akuster@pacbell.net
+ * =A0Sept, 2001
+ *
+ * =A0Orignial driver
+ * =A0Author: MontaVista Software, Inc. =A0[off-list ref]
+ * =A0 =A0 =A0 =A0 =A0Frank Rowand [off-list ref]
+ * =A0 =A0 =A0 =A0 =A0Debbie Chu =A0 [off-list ref]
+ *
+ * Copyright 2000,2001,2002 MontaVista Software Inc.

Any new copyright year?

+ *=A0=A0=A0=A0=A0TODO: devfs

surely not.

+ *=A0=A0=A0=A0=A0Version: 02/01/12 - Armin
+ *=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 conver=

ted to ocp and using ioremap

+ *
+ *=A0=A0=A0=A0=A01.2 02/21/01 - Armin
+ *=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0minor compiler warning fixes
+ *
+ *=A0=A0=A0=A0=A01.3 02/22/01 - Armin
+ *=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0added apm
+ *
+ *=A0=A0=A0=A0=A01.4 05/07/02 - Armin/David Mueller
+ *=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0coverted to core_ocp[];
+ *
+ *=A0=A0=A0=A0=A01.5 05/25/02 - Armin
+ *=A0=A0=A0=A0=A0 name change from *_driver to *_dev
+ *
+ *=A0=A0=A0=A0=A01.6 06/04/02 - Matt Porter
+ *=A0=A0=A0=A0=A0ioremap paddr. Comment as 4xx generic driver.
+ *=A0=A0=A0=A0=A0Fix header to be userland safe and locate in
+ *=A0=A0=A0=A0=A0an accessible area. =A0Add ioctl to configure
+ *=A0=A0=A0=A0=A0multiplexed GPIO pins.
+ *
+ *=A0=A0=A0=A0=A01.7 07/25/02 - Armin
+ *=A0=A0=A0=A0=A0added CPM to enable/disable in init/exit

kill that changelog

+ */
+
+#define VUFX "07.25.02"

should be MODULE_VERSION()

+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/ioctl.h>
+#include <linux/fs.h>
+#include <asm/ibm_gpio.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/machdep.h>
+#include <asm/ocp.h>
+#include <asm/ibm4xx.h>
+
+struct miscdevice ibm_gpio_miscdev;
+static struct gpio_regs *gpiop;
+
+int
+ibm_gpio_config(__u32 device, __u32 mask, __u32 data)

any symbols should be static. Function arguments are not
visible to users, so they should be 'u32' instead of '__u32'.

+{
+=A0=A0=A0=A0=A0=A0=A0u32 cfg_reg;
+
+=A0=A0=A0=A0=A0=A0=A0if (device !=3D 0)
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0return -ENXIO;
+
+#ifdef CONFIG_40x
+#ifdef DCRN_CHCR0
+=A0=A0=A0=A0=A0=A0=A0/*
+=A0=A0=A0=A0=A0=A0=A0 * PPC405 uses CPC0_CR0 to select multiplexed GPIO =

pins.

+=A0=A0=A0=A0=A0=A0=A0 */
+=A0=A0=A0=A0=A0=A0=A0cfg_reg =3D mfdcr(DCRN_CHCR0);
+=A0=A0=A0=A0=A0=A0=A0cfg_reg =3D (cfg_reg & ~mask) | (data & mask);
+=A0=A0=A0=A0=A0=A0=A0mtdcr(DCRN_CHCR0, cfg_reg);
+#endif
+#elif CONFIG_440GP
+=A0=A0=A0=A0=A0=A0=A0/*
+=A0=A0=A0=A0=A0=A0=A0 * PPC440GP uses CPC0_GPIO to select multiplexed GP=

IO pins.

+=A0=A0=A0=A0=A0=A0=A0 */
+=A0=A0=A0=A0=A0=A0=A0cfg_reg =3D mfdcr(DCRN_CPC0_GPIO);
+=A0=A0=A0=A0=A0=A0=A0cfg_reg =3D (cfg_reg & ~mask) | (data & mask);
+=A0=A0=A0=A0=A0=A0=A0mtdcr(DCRN_CPC0_GPIO, cfg_reg);
+#elif CONFIG_440GX
+=A0=A0=A0=A0=A0=A0=A0/*
+=A0=A0=A0=A0=A0=A0=A0 * PPC440GX uses SDR0_PFC0 to select multiplexed GP=

IO pins

+=A0=A0=A0=A0=A0=A0=A0 */
+=A0=A0=A0=A0=A0=A0=A0cfg_reg =3D SDR_READ(DCRN_SDR_PFC0);
+=A0=A0=A0=A0=A0=A0=A0cfg_reg =3D (cfg_reg & ~mask) | (data & mask);
+=A0=A0=A0=A0=A0=A0=A0SDR_WRITE(DCRN_SDR_PFC0, cfg_reg);
+#else
+#error This driver is only supported on PPC40x and PPC440 CPUs
+#endif

This prevents building a single kernel for multiple 440 version.
Please use a run-time check, or better get the necessary information
from the device tree.

+int
+ibm_gpio_in(__u32 device, __u32 mask, volatile __u32 * data)
+{
+=A0=A0=A0=A0=A0=A0=A0if (device !=3D 0)
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0return -ENXIO;
+=A0=A0=A0=A0=A0=A0=A0gpiop->tcr =3D gpiop->tcr & ~mask;
+=A0=A0=A0=A0=A0=A0=A0eieio();
+
+=A0=A0=A0=A0=A0=A0=A0/*
+=A0=A0=A0=A0=A0=A0=A0 =A0 ** If the previous state was OUT, and gpiop->i=

r is read once, then the

+=A0=A0=A0=A0=A0=A0=A0 =A0 ** data that was being OUTput will be read. =

=A0One way to get the right

+=A0=A0=A0=A0=A0=A0=A0 =A0 ** data is to read gpiop->ir twice.
+=A0=A0=A0=A0=A0=A0=A0 */
+
+=A0=A0=A0=A0=A0=A0=A0*data =3D gpiop->ir;
+=A0=A0=A0=A0=A0=A0=A0*data =3D gpiop->ir & mask;
+=A0=A0=A0=A0=A0=A0=A0eieio();
+=A0=A0=A0=A0=A0=A0=A0return 0;
+}

Don't just assign *data, make that an __iomem pointer and use
an appropriate accessor function (out_be32 or such).

+
+static int
+ibm_gpio_open(struct inode *inode, struct file *file)
+{
+=A0=A0=A0=A0=A0=A0=A0return 0;
+}
+
+static int
+ibm_gpio_release(struct inode *inode, struct file *file)
+{
+=A0=A0=A0=A0=A0=A0=A0return 0;
+}

You don't need these.

+static int
+ibm_gpio_ioctl(struct inode *inode, struct file *file,
+=A0=A0=A0=A0=A0=A0=A0 =A0 =A0 =A0 unsigned int cmd, unsigned long arg)
+{
+=A0=A0=A0=A0=A0=A0=A0static struct ibm_gpio_ioctl_data ioctl_data;
+=A0=A0=A0=A0=A0=A0=A0int status;
+
+=A0=A0=A0=A0=A0=A0=A0switch (cmd) {
+=A0=A0=A0=A0=A0=A0=A0case IBMGPIO_IN:
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0if (copy_from_user(&ioctl_d=

ata,

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=

=A0=A0=A0=A0=A0=A0=A0 =A0 (struct ibm_gpio_ioctl_data *) arg,

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=

=A0=A0=A0=A0=A0=A0=A0 =A0 sizeof (ioctl_data))) {

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0ret=

urn -EFAULT;

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0}

Just do the copy_from_user() once, in the beginning here, instead
of each case.

+
+static int __init
+ibm_gpio_probe(struct ocp_device *ocp)
+{
+=A0=A0=A0=A0=A0=A0=A0ibm_gpio_miscdev.minor =3D GPIO_MINOR;
+=A0=A0=A0=A0=A0=A0=A0ibm_gpio_miscdev.name =3D ocp->name;
+=A0=A0=A0=A0=A0=A0=A0ibm_gpio_miscdev.fops =3D &ibm_gpio_fops;
+=A0=A0=A0=A0=A0=A0=A0misc_register(&ibm_gpio_miscdev);
+
+=A0=A0=A0=A0=A0=A0=A0if (!request_mem_region(ocp->def->paddr, sizeof(str=

uct gpio_regs), "ibm_gpio"))

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0return -EBUSY;
+=A0=A0=A0=A0=A0=A0=A0
+=A0=A0=A0=A0=A0=A0=A0gpiop =3D (struct gpio_regs *) ioremap(ocp->def->pa=

ddr,

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0siz=

eof(struct gpio_regs));

+=A0=A0=A0=A0=A0=A0=A0if (!gpiop) {
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0release_mem_region(ocp->def=

=2D>paddr, sizeof(struct gpio_regs));

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0return -ENOMEM;
+=A0=A0=A0=A0=A0=A0=A0}
+=A0=A0=A0=A0=A0=A0=A0
+=A0=A0=A0=A0=A0=A0=A0printk("GPIO #%d at 0x%lx\n", ocp->def->index,
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0(un=

signed long) gpiop);

+
+=A0=A0=A0=A0=A0=A0=A0return 0;
+}
+
+static void __exit
+ibm_gpio_remove(struct ocp_device *ocp)
+{
+=A0=A0=A0=A0=A0=A0=A0misc_deregister(&ibm_gpio_miscdev);
+
+=A0=A0=A0=A0=A0=A0=A0iounmap(gpiop);
+=A0=A0=A0=A0=A0=A0=A0gpiop =3D NULL;
+=A0=A0=A0=A0=A0=A0=A0
+=A0=A0=A0=A0=A0=A0=A0release_mem_region(ocp->def->paddr, sizeof(struct g=

pio_regs));

+}
+
+static struct ocp_device_id ibm_gpio_ids[] __devinitdata =3D
+{
+=A0=A0=A0=A0=A0=A0=A0{ .vendor =3D OCP_VENDOR_IBM, .function =3D OCP_FUN=

C_GPIO },

+=A0=A0=A0=A0=A0=A0=A0{ .vendor =3D OCP_VENDOR_INVALID }
+};
+
+MODULE_DEVICE_TABLE(ocp, ibm_gpio_ids);
+
+static struct ocp_driver ibm_gpio_driver =3D
+{
+=A0=A0=A0=A0=A0=A0=A0.name =A0 =A0 =A0 =A0 =A0 =3D "ibm_gpio",
+=A0=A0=A0=A0=A0=A0=A0.id_table =A0 =A0 =A0 =3D ibm_gpio_ids,
+=A0=A0=A0=A0=A0=A0=A0.probe =A0 =A0 =A0 =A0 =A0=3D ibm_gpio_probe,
+=A0=A0=A0=A0=A0=A0=A0.remove =A0 =A0 =A0 =A0 =3D __devexit_p(ibm_gpio_re=

move),

+#if defined(CONFIG_PM)
+=A0=A0=A0=A0=A0=A0=A0.suspend =A0 =A0 =A0 =A0=3D NULL,
+=A0=A0=A0=A0=A0=A0=A0.resume =A0 =A0 =A0 =A0 =3D NULL,
+#endif
+};
+
+static int __init
+ibm_gpio_init(void)
+{
+=A0=A0=A0=A0=A0=A0=A0printk("IBM GPIO driver version %s\n", VUFX);
+=A0=A0=A0=A0=A0=A0=A0return ocp_register_driver(&ibm_gpio_driver);
+}
+
+static void __exit
+ibm_gpio_exit(void)
+{
+=A0=A0=A0=A0=A0=A0=A0ocp_unregister_driver(&ibm_gpio_driver);
+}

ocp will die a painful death soon, when 440 has been converted over
to use the device tree and of_device.

+EXPORT_SYMBOL(ibm_gpio_tristate);
+EXPORT_SYMBOL(ibm_gpio_open_drain);
+EXPORT_SYMBOL(ibm_gpio_in);
+EXPORT_SYMBOL(ibm_gpio_out);

Why export these at all? They don't seem to be used elsewhere?

If you need to export them, make it EXPORT_SYMBOL_GPL and put that
line directly under the functions.

+
+struct ibm_gpio_ioctl_data {
+ =A0 =A0 =A0 =A0__u32 device;
+ =A0 =A0 =A0 =A0__u32 mask;
+ =A0 =A0 =A0 =A0__u32 data;
+};
+
+#define IBMGPIO_IOCTL_BASE=A0=A0=A0=A0=A0'Z'
+
+#define IBMGPIO_IN=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0_IOWR(IBMGPIO_I=

OCTL_BASE, 0, struct ibm_gpio_ioctl_data)

+#define IBMGPIO_OUT=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0_IOW (IBMGPIO_IOC=

TL_BASE, 1, struct ibm_gpio_ioctl_data)

+#define IBMGPIO_OPEN_DRAIN=A0=A0=A0=A0=A0_IOW (IBMGPIO_IOCTL_BASE, 2, st=

ruct ibm_gpio_ioctl_data)

+#define IBMGPIO_TRISTATE=A0=A0=A0=A0=A0=A0=A0_IOW (IBMGPIO_IOCTL_BASE, 3=

, struct ibm_gpio_ioctl_data)

+#define IBMGPIO_CFG=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0_IOW (IBMGPIO_IOC=

TL_BASE, 4, struct ibm_gpio_ioctl_data)

Is that the same ioctl interface as for the other gpio drivers?

+#endif

On Fri, Sep 29, 2006 at 11:06:19AM +0200, Arnd Bergmann wrote:

quoted

+{
+       u32 cfg_reg;
+
+       if (device != 0)
+               return -ENXIO;
+
+#ifdef CONFIG_40x
+#ifdef DCRN_CHCR0
+       /*
+        * PPC405 uses CPC0_CR0 to select multiplexed GPIO pins.
+        */
+       cfg_reg = mfdcr(DCRN_CHCR0);
+       cfg_reg = (cfg_reg & ~mask) | (data & mask);
+       mtdcr(DCRN_CHCR0, cfg_reg);
+#endif
+#elif CONFIG_440GP
+       /*
+        * PPC440GP uses CPC0_GPIO to select multiplexed GPIO pins.
+        */
+       cfg_reg = mfdcr(DCRN_CPC0_GPIO);
+       cfg_reg = (cfg_reg & ~mask) | (data & mask);
+       mtdcr(DCRN_CPC0_GPIO, cfg_reg);
+#elif CONFIG_440GX
+       /*
+        * PPC440GX uses SDR0_PFC0 to select multiplexed GPIO pins
+        */
+       cfg_reg = SDR_READ(DCRN_SDR_PFC0);
+       cfg_reg = (cfg_reg & ~mask) | (data & mask);
+       SDR_WRITE(DCRN_SDR_PFC0, cfg_reg);
+#else
+#error This driver is only supported on PPC40x and PPC440 CPUs
+#endif

This prevents building a single kernel for multiple 440 version.
Please use a run-time check, or better get the necessary information
from the device tree.

440 kernels _are_ built for each particular 440 chip separately, and 
not all these defines are even available simultaneously.

So, frankly, I don't understand your complain here. We don't support 
single kernel image running on different 440s. Also, last time I 
checked, 440 port wasn't using device tree as well.

-- 
Eugene