Commit 74ded38a authored by Thomas Bogendoerfer's avatar Thomas Bogendoerfer Committed by Greg Kroah-Hartman
Browse files

w1: add 1-wire master driver for IP block found in SGI ASICs 



Starting with SGI Origin machines nearly every new SGI ASIC contains
an 1-Wire master. They are used for attaching One-Wire prom devices,
which contain information about part numbers, revision numbers,
serial number etc. and MAC addresses for ethernet interfaces.
This patch adds a master driver to support this IP block.
It also adds an extra field dev_id to struct w1_bus_master, which
could be in used in slave drivers for creating unique device names.

Signed-off-by: default avatarThomas Bogendoerfer <tbogendoerfer@suse.de>
Link: https://lore.kernel.org/r/20190831082623.15627-2-tbogendoerfer@suse.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 836e9494

drivers/w1/masters/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -65,5 +65,14 @@ config HDQ_MASTER_OMAP 
	  Say Y here if you want support for the 1-wire or HDQ Interface

	  on an OMAP processor.



config W1_MASTER_SGI

	tristate "SGI ASIC driver"

	help

	  Say Y here if you want support for your 1-wire devices using

	  SGI ASIC 1-Wire interface



	  This support is also available as a module.  If so, the module

	  will be called sgi_w1.



endmenu

drivers/w1/masters/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -11,3 +11,4 @@ obj-$(CONFIG_W1_MASTER_MXC) += mxc_w1.o 
obj-$(CONFIG_W1_MASTER_DS1WM)		+= ds1wm.o

obj-$(CONFIG_W1_MASTER_GPIO)		+= w1-gpio.o

obj-$(CONFIG_HDQ_MASTER_OMAP)		+= omap_hdq.o

obj-$(CONFIG_W1_MASTER_SGI)		+= sgi_w1.o

drivers/w1/masters/sgi_w1.c

0 → 100644
+130 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * sgi_w1.c - w1 master driver for one wire support in SGI ASICs

 */



#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/io.h>

#include <linux/jiffies.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/platform_device.h>

#include <linux/platform_data/sgi-w1.h>



#include <linux/w1.h>



#define MCR_RD_DATA	BIT(0)

#define MCR_DONE	BIT(1)



#define MCR_PACK(pulse, sample) (((pulse) << 10) | ((sample) << 2))



struct sgi_w1_device {

	u32 __iomem *mcr;

	struct w1_bus_master bus_master;

	char dev_id[64];

};



static u8 sgi_w1_wait(u32 __iomem *mcr)

{

	u32 mcr_val;



	do {

		mcr_val = readl(mcr);

	} while (!(mcr_val & MCR_DONE));



	return (mcr_val & MCR_RD_DATA) ? 1 : 0;

}



/*

 * this is the low level routine to

 * reset the device on the One Wire interface

 * on the hardware

 */

static u8 sgi_w1_reset_bus(void *data)

{

	struct sgi_w1_device *dev = data;

	u8 ret;



	writel(MCR_PACK(520, 65), dev->mcr);

	ret = sgi_w1_wait(dev->mcr);

	udelay(500); /* recovery time */

	return ret;

}



/*

 * 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 sgi_w1_touch_bit(void *data, u8 bit)

{

	struct sgi_w1_device *dev = data;

	u8 ret;



	if (bit)

		writel(MCR_PACK(6, 13), dev->mcr);

	else

		writel(MCR_PACK(80, 30), dev->mcr);



	ret = sgi_w1_wait(dev->mcr);

	if (bit)

		udelay(100); /* recovery */

	return ret;

}



static int sgi_w1_probe(struct platform_device *pdev)

{

	struct sgi_w1_device *sdev;

	struct sgi_w1_platform_data *pdata;

	struct resource *res;



	sdev = devm_kzalloc(&pdev->dev, sizeof(struct sgi_w1_device),

			    GFP_KERNEL);

	if (!sdev)

		return -ENOMEM;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	sdev->mcr = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(sdev->mcr))

		return PTR_ERR(sdev->mcr);



	sdev->bus_master.data = sdev;

	sdev->bus_master.reset_bus = sgi_w1_reset_bus;

	sdev->bus_master.touch_bit = sgi_w1_touch_bit;



	pdata = dev_get_platdata(&pdev->dev);

	if (pdata) {

		strlcpy(sdev->dev_id, pdata->dev_id, sizeof(sdev->dev_id));

		sdev->bus_master.dev_id = sdev->dev_id;

	}



	platform_set_drvdata(pdev, sdev);



	return w1_add_master_device(&sdev->bus_master);

}



/*

 * disassociate the w1 device from the driver

 */

static int sgi_w1_remove(struct platform_device *pdev)

{

	struct sgi_w1_device *sdev = platform_get_drvdata(pdev);



	w1_remove_master_device(&sdev->bus_master);



	return 0;

}



static struct platform_driver sgi_w1_driver = {

	.driver = {

		.name = "sgi_w1",

	},

	.probe = sgi_w1_probe,

	.remove = sgi_w1_remove,

};

module_platform_driver(sgi_w1_driver);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Thomas Bogendoerfer");

MODULE_DESCRIPTION("Driver for One-Wire IP in SGI ASICs");

include/linux/platform_data/sgi-w1.h

0 → 100644
+13 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * SGI One-Wire (W1) IP

 */



#ifndef PLATFORM_DATA_SGI_W1_H

#define PLATFORM_DATA_SGI_W1_H



struct sgi_w1_platform_data {

	char dev_id[64];

};



#endif /* PLATFORM_DATA_SGI_W1_H */

include/linux/w1.h

+5 −0
Original line number Diff line number Diff line
@@ -118,6 +118,9 @@ typedef void (*w1_slave_found_callback)(struct w1_master *, u64); 
 * w1_master* is passed to the slave found callback.

 * u8 is search_type, W1_SEARCH or W1_ALARM_SEARCH

 *

 * @dev_id: Optional device id string, which w1 slaves could use for

 * creating names, which then give a connection to the w1 master

 *

 * Note: read_bit and write_bit are very low level functions and should only

 * be used with hardware that doesn't really support 1-wire operations,

 * like a parallel/serial port.
@@ -150,6 +153,8 @@ struct w1_bus_master { 


	void		(*search)(void *, struct w1_master *,

		u8, w1_slave_found_callback);



	char		*dev_id;

};



/**