Messages in this thread Patch in this message | | | Date | Fri, 21 Nov 2008 11:12:04 +0100 | From | Sascha Hauer <> | Subject | Re: [PATCH] Add 1-wire master driver for i.MX27 / i.MX31 |
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Hi Andrew,
Sorry for the delay, we are moving to a new office at the moment.
On Wed, Nov 19, 2008 at 12:19:32AM -0800, Andrew Morton wrote: > On Wed, 19 Nov 2008 01:16:13 +0300 Evgeniy Polyakov <zbr@ioremap.net> wrote: > > > From: Sascha Hauer <s.hauer@pengutronix.de> > > > > This patch adds support for the 1-wire master interface for i.MX27 and > > i.MX31. > > Looks sane. > > > Ack for this one, the other patches from this series need to go via > > Russell King to prevent merge conflicts with other MX2 patches. Sorry, I > > should have made that clear. > > Is this patch fully independent of the others?
The first patch adds a platform driver and the other patches add users for this driver. Otherwise they are independent.
> > > > > ... > > > > +static int __devinit mxc_w1_probe(struct platform_device *pdev) > > +{ > > + struct mxc_w1_device *mdev; > > + struct resource *res; > > + int err = 0; > > + > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + if (!res) > > + return -ENODEV; > > + > > + mdev = kzalloc(sizeof(struct mxc_w1_device) + > > + sizeof(struct w1_bus_master), GFP_KERNEL); > > whee, that's a bit of a hack. It would be better to do > > struct foo { > struct mxc_w1_device mxc_w1_device; > struct w1_bus_master w1_bus_master; > }; > > no?
Uh, yes that's indeed a hack. I changed it to:
struct mxc_w1_device { [...] struct w1_bus_master bus_master; };
> > > + if (!mdev) > > + return -ENOMEM; > > + > > + mdev->clk = clk_get(&pdev->dev, "owire_clk"); > > + if (!mdev->clk) { > > + err = -ENODEV; > > + goto failed_clk; > > + } > > + > > + mdev->bus_master = (struct w1_bus_master *)(mdev + 1); > > + mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1; > > If that 1000000 refers to microseconds then the use of USEC_PER_SEC > would be clearer.
No, it's clk_get_rate() in Hz divided by 1000000 Hz to get a plain divider without unit.
Here's an updated version of the patch. Let me know if you want a patch against your tree instead.
Sascha
commit 8259cf2a77b1f2aa215940576f5a55ce72e58a64 Author: Sascha Hauer <s.hauer@pengutronix.de> Date: Wed Nov 12 16:19:22 2008 +0100
Add 1-wire master driver for i.MX27 / i.MX31 This patch adds support for the 1-wire master interface for i.MX27 and i.MX31. Signed-off-by: Luotao Fu <l.fu@pengutronix.de> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/Documentation/w1/masters/00-INDEX b/Documentation/w1/masters/00-INDEX index 7b0ceaa..d63fa02 100644 --- a/Documentation/w1/masters/00-INDEX +++ b/Documentation/w1/masters/00-INDEX @@ -4,5 +4,7 @@ ds2482 - The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses. ds2490 - The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges. +mxc_w1 + - W1 master controller driver found on Freescale MX2/MX3 SoCs w1-gpio - GPIO 1-wire bus master driver. diff --git a/Documentation/w1/masters/mxc-w1 b/Documentation/w1/masters/mxc-w1 new file mode 100644 index 0000000..97f6199 --- /dev/null +++ b/Documentation/w1/masters/mxc-w1 @@ -0,0 +1,11 @@ +Kernel driver mxc_w1 +==================== + +Supported chips: + * Freescale MX27, MX31 and probably other i.MX SoCs + Datasheets: + http://www.freescale.com/files/32bit/doc/data_sheet/MCIMX31.pdf?fpsp=1 + http://www.freescale.com/files/dsp/MCIMX27.pdf?fpsp=1 + +Author: Originally based on Freescale code, prepared for mainline by + Sascha Hauer <s.hauer@pengutronix.de> diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig index c449309..d4f8050 100644 --- a/drivers/w1/masters/Kconfig +++ b/drivers/w1/masters/Kconfig @@ -34,6 +34,12 @@ config W1_MASTER_DS2482 This driver can also be built as a module. If so, the module will be called ds2482. +config W1_MASTER_MXC + tristate "Freescale MXC 1-wire busmaster" + depends on W1 && ARCH_MXC + help + Say Y here to enable MXC 1-wire host + config W1_MASTER_DS1WM tristate "Maxim DS1WM 1-wire busmaster" depends on W1 && ARM diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile index 1420b5b..6c61e22 100644 --- a/drivers/w1/masters/Makefile +++ b/drivers/w1/masters/Makefile @@ -5,5 +5,7 @@ obj-$(CONFIG_W1_MASTER_MATROX) += matrox_w1.o obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o +obj-$(CONFIG_W1_MASTER_MXC) += mxc_w1.o + obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c new file mode 100644 index 0000000..b9d74d0 --- /dev/null +++ b/drivers/w1/masters/mxc_w1.c @@ -0,0 +1,211 @@ +/* + * Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2008 Luotao Fu, kernel@pengutronix.de + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + */ + +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> + +#include "../w1.h" +#include "../w1_int.h" +#include "../w1_log.h" + +/* According to the mx27 Datasheet the reset procedure should take up to about + * 1350us. We set the timeout to 500*100us = 50ms for sure */ +#define MXC_W1_RESET_TIMEOUT 500 + +/* + * MXC W1 Register offsets + */ +#define MXC_W1_CONTROL 0x00 +#define MXC_W1_TIME_DIVIDER 0x02 +#define MXC_W1_RESET 0x04 +#define MXC_W1_COMMAND 0x06 +#define MXC_W1_TXRX 0x08 +#define MXC_W1_INTERRUPT 0x0A +#define MXC_W1_INTERRUPT_EN 0x0C + +struct mxc_w1_device { + void __iomem *regs; + unsigned int clkdiv; + struct clk *clk; + struct w1_bus_master bus_master; +}; + +/* + * this is the low level routine to + * reset the device on the One Wire interface + * on the hardware + */ +static u8 mxc_w1_ds2_reset_bus(void *data) +{ + u8 reg_val; + unsigned int timeout_cnt = 0; + struct mxc_w1_device *dev = data; + + __raw_writeb(0x80, (dev->regs + MXC_W1_CONTROL)); + + while (1) { + reg_val = __raw_readb(dev->regs + MXC_W1_CONTROL); + + if (((reg_val >> 7) & 0x1) == 0 || + timeout_cnt > MXC_W1_RESET_TIMEOUT) + break; + else + timeout_cnt++; + + udelay(100); + } + return (reg_val >> 7) & 0x1; +} + +/* + * this is the low level routine to read/write a bit on the One Wire + * interface on the hardware. It does write 0 if parameter bit is set + * to 0, otherwise a write 1/read. + */ +static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit) +{ + struct mxc_w1_device *mdev = data; + void __iomem *ctrl_addr = mdev->regs + MXC_W1_CONTROL; + unsigned int timeout_cnt = 400; /* Takes max. 120us according to + * datasheet. + */ + + __raw_writeb((1 << (5 - bit)), ctrl_addr); + + while (timeout_cnt--) { + if (!((__raw_readb(ctrl_addr) >> (5 - bit)) & 0x1)) + break; + + udelay(1); + } + + return ((__raw_readb(ctrl_addr)) >> 3) & 0x1; +} + +static int __init mxc_w1_probe(struct platform_device *pdev) +{ + struct mxc_w1_device *mdev; + struct resource *res; + int err = 0; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + mdev = kzalloc(sizeof(struct mxc_w1_device), GFP_KERNEL); + if (!mdev) + return -ENOMEM; + + mdev->clk = clk_get(&pdev->dev, "owire_clk"); + if (!mdev->clk) { + err = -ENODEV; + goto failed_clk; + } + + mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1; + + res = request_mem_region(res->start, resource_size(res), + "mxc_w1"); + if (!res) { + err = -EBUSY; + goto failed_req; + } + + mdev->regs = ioremap(res->start, resource_size(res)); + if (!mdev->regs) { + printk(KERN_ERR "Cannot map frame buffer registers\n"); + goto failed_ioremap; + } + + clk_enable(mdev->clk); + __raw_writeb(mdev->clkdiv, mdev->regs + MXC_W1_TIME_DIVIDER); + + mdev->bus_master.data = mdev; + mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus; + mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit; + + err = w1_add_master_device(&mdev->bus_master); + + if (err) + goto failed_add; + + platform_set_drvdata(pdev, mdev); + return 0; + +failed_add: + iounmap(mdev->regs); +failed_ioremap: + release_mem_region(res->start, resource_size(res)); +failed_req: + clk_put(mdev->clk); +failed_clk: + kfree(mdev); + return err; +} + +/* + * disassociate the w1 device from the driver + */ +static int mxc_w1_remove(struct platform_device *pdev) +{ + struct mxc_w1_device *mdev = platform_get_drvdata(pdev); + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + w1_remove_master_device(&mdev->bus_master); + + iounmap(mdev->regs); + release_mem_region(res->start, resource_size(res)); + clk_disable(mdev->clk); + clk_put(mdev->clk); + + platform_set_drvdata(pdev, NULL); + + return 0; +} + +static struct platform_driver mxc_w1_driver = { + .driver = { + .name = "mxc_w1", + }, + .probe = mxc_w1_probe, + .remove = mxc_w1_remove, +}; + +static int __init mxc_w1_init(void) +{ + return platform_driver_register(&mxc_w1_driver); +} + +static void mxc_w1_exit(void) +{ + platform_driver_unregister(&mxc_w1_driver); +} + +module_init(mxc_w1_init); +module_exit(mxc_w1_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Freescale Semiconductors Inc"); +MODULE_DESCRIPTION("Driver for One-Wire on MXC"); -- Pengutronix - Linux Solutions for Science and Industry Handelsregister: Amtsgericht Hildesheim, HRA 2686 Hannoversche Str. 2, 31134 Hildesheim, Germany Phone: +49-5121-206917-0 | Fax: +49-5121-206917-9
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