lkml.org 
[lkml]   [2019]   [Aug]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 1/2] w1: add 1-wire master driver for IP block found in SGI ASICs
Date
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: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/w1/masters/Kconfig | 9 +++
drivers/w1/masters/Makefile | 1 +
drivers/w1/masters/sgi_w1.c | 130 +++++++++++++++++++++++++++++++++++
include/linux/platform_data/sgi-w1.h | 15 ++++
include/linux/w1.h | 5 ++
5 files changed, 160 insertions(+)
create mode 100644 drivers/w1/masters/sgi_w1.c
create mode 100644 include/linux/platform_data/sgi-w1.h

diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
index 7ae260577901..24b9a8e05f64 100644
--- a/drivers/w1/masters/Kconfig
+++ b/drivers/w1/masters/Kconfig
@@ -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

diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
index 18954cae4256..dae629b7ab49 100644
--- a/drivers/w1/masters/Makefile
+++ b/drivers/w1/masters/Makefile
@@ -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
diff --git a/drivers/w1/masters/sgi_w1.c b/drivers/w1/masters/sgi_w1.c
new file mode 100644
index 000000000000..1b2d96b945be
--- /dev/null
+++ b/drivers/w1/masters/sgi_w1.c
@@ -0,0 +1,130 @@
+// 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");
diff --git a/include/linux/platform_data/sgi-w1.h b/include/linux/platform_data/sgi-w1.h
new file mode 100644
index 000000000000..fc6b92e0b942
--- /dev/null
+++ b/include/linux/platform_data/sgi-w1.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SGI One-Wire (W1) IP
+ */
+
+#ifndef PLATFORM_DATA_SGI_W1_H
+#define PLATFORM_DATA_SGI_W1_H
+
+#include <asm/sn/types.h>
+
+struct sgi_w1_platform_data {
+ char dev_id[64];
+};
+
+#endif /* PLATFORM_DATA_SGI_W1_H */
diff --git a/include/linux/w1.h b/include/linux/w1.h
index e0b5156f78fd..7da0c7588e04 100644
--- a/include/linux/w1.h
+++ b/include/linux/w1.h
@@ -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;
};

/**
--
2.13.7
\
 
 \ /
  Last update: 2019-08-30 20:50    [W:0.049 / U:1.708 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site