[U-Boot] [PATCH v4 01/34] w1: Add 1-Wire uclass

Eugen Hristev
2018-09-18T07:35:24Z

From: Maxime Ripard <maxime.ripard@free-electrons.com>

We might want to use 1-Wire devices connected on boards such as EEPROMs in
U-Boot.

Provide a framework to be able to do that.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
[eugen.hristev at microchip.com: reworked]
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/w1/Kconfig | 18 ++++
drivers/w1/Makefile | 1 +
drivers/w1/w1-uclass.c | 236 +++++++++++++++++++++++++++++++++++++++++++++++++
include/dm/uclass-id.h | 1 +
include/w1.h | 36 ++++++++
7 files changed, 295 insertions(+)
create mode 100644 drivers/w1/Kconfig
create mode 100644 drivers/w1/Makefile
create mode 100644 drivers/w1/w1-uclass.c
create mode 100644 include/w1.h

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 56536c4..6f91eac 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -106,6 +106,8 @@ source "drivers/usb/Kconfig"

source "drivers/video/Kconfig"

+source "drivers/w1/Kconfig"
+
source "drivers/watchdog/Kconfig"

config PHYS_TO_BUS
diff --git a/drivers/Makefile b/drivers/Makefile
index 23ea609..4ca07c3 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -105,6 +105,7 @@ obj-y += smem/
obj-y += soc/
obj-y += thermal/
obj-y += axi/
+obj-$(CONFIG_W1) += w1/

obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
endif
diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig
new file mode 100644
index 0000000..64b27c6
--- /dev/null
+++ b/drivers/w1/Kconfig
@@ -0,0 +1,18 @@
+#
+# W1 subsystem configuration
+#
+
+menu "1-Wire support"
+
+config W1
+ bool "Enable 1-wire controllers support"
+ default no
+ depends on DM
+ help
+ Support for the Dallas 1-Wire bus.
+
+if W1
+
+endif
+
+endmenu
diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile
new file mode 100644
index 0000000..f81693b
--- /dev/null
+++ b/drivers/w1/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_W1) += w1-uclass.o
diff --git a/drivers/w1/w1-uclass.c b/drivers/w1/w1-uclass.c
new file mode 100644
index 0000000..44759fe
--- /dev/null
+++ b/drivers/w1/w1-uclass.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co.
+ * Copyright (c) 2018 Microchip Technology, Inc.
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ * Eugen Hristev <eugen.hristev@microchip.com>
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <w1.h>
+
+#include <dm/device-internal.h>
+
+#define W1_MATCH_ROM 0x55
+#define W1_SKIP_ROM 0xcc
+#define W1_SEARCH 0xf0
+
+struct w1_bus {
+ u64 search_id;
+};
+
+static int w1_enumerate(struct udevice *bus)
+{
+ const struct w1_ops *ops = device_get_ops(bus);
+ struct w1_bus *w1 = dev_get_uclass_priv(bus);
+ u64 last_rn, rn = w1->search_id, tmp64;
+ bool last_device = false;
+ int search_bit, desc_bit = 64;
+ int last_zero = -1;
+ u8 triplet_ret = 0;
+ int i;
+
+ if (!ops->reset || !ops->write_byte || !ops->triplet)
+ return -ENOSYS;
+
+ while (!last_device) {
+ last_rn = rn;
+ rn = 0;
+
+ /*
+ * Reset bus and all 1-wire device state machines
+ * so they can respond to our requests.
+ *
+ * Return 0 - device(s) present, 1 - no devices present.
+ */
+ if (ops->reset(bus)) {
+ debug("%s: No devices present on the wire.\n",
+ __func__);
+ break;
+ }
+
+ /* Start the search */
+ ops->write_byte(bus, W1_SEARCH);
+ for (i = 0; i < 64; ++i) {
+ /* Determine the direction/search bit */
+ if (i == desc_bit)
+ /* took the 0 path last time, so take the 1 path */
+ search_bit = 1;
+ else if (i > desc_bit)
+ /* take the 0 path on the next branch */
+ search_bit = 0;
+ else
+ search_bit = ((last_rn >> i) & 0x1);
+
+ /* Read two bits and write one bit */
+ triplet_ret = ops->triplet(bus, search_bit);
+
+ /* quit if no device responded */
+ if ((triplet_ret & 0x03) == 0x03)
+ break;
+
+ /* If both directions were valid, and we took the 0 path... */
+ if (triplet_ret == 0)
+ last_zero = i;
+
+ /* extract the direction taken & update the device number */
+ tmp64 = (triplet_ret >> 2);
+ rn |= (tmp64 << i);
+ }
+
+ /* last device or error, aborting here */
+ if ((triplet_ret & 0x03) == 0x03)
+ last_device = true;
+
+ if ((triplet_ret & 0x03) != 0x03) {
+ if (desc_bit == last_zero || last_zero < 0) {
+ last_device = 1;
+ w1->search_id = 0;
+ } else {
+ w1->search_id = rn;
+ }
+ desc_bit = last_zero;
+
+ debug("%s: Detected new device 0x%llx (family 0x%x)\n",
+ bus->name, rn, (u8)(rn & 0xff));
+ }
+ }
+
+ return 0;
+}
+
+int w1_get_bus(int busnum, struct udevice **busp)
+{
+ int ret, i = 0;
+
+ struct udevice *dev;
+
+ for (ret = uclass_first_device(UCLASS_W1, &dev);
+ !ret;
+ uclass_next_device(&dev), i++) {
+ if (ret) {
+ debug("Cannot find w1 bus %d\n", busnum);
+ return ret;
+ }
+ if (i == busnum) {
+ *busp = dev;
+ return 0;
+ }
+ }
+ return ret;
+}
+
+u8 w1_get_device_family(struct udevice *dev)
+{
+ struct w1_device *w1 = dev_get_parent_platdata(dev);
+
+ return w1->id & 0xff;
+}
+
+int w1_reset_select(struct udevice *dev)
+{
+ struct w1_device *w1 = dev_get_parent_platdata(dev);
+ struct udevice *bus = dev_get_parent(dev);
+ const struct w1_ops *ops = device_get_ops(bus);
+ int i;
+
+ if (!ops->reset || !ops->write_byte)
+ return -ENOSYS;
+
+ ops->reset(bus);
+
+ ops->write_byte(bus, W1_MATCH_ROM);
+
+ for (i = 0; i < sizeof(w1->id); i++)
+ ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff);
+
+ return 0;
+}
+
+int w1_read_byte(struct udevice *dev)
+{
+ struct udevice *bus = dev_get_parent(dev);
+ const struct w1_ops *ops = device_get_ops(bus);
+
+ if (!ops->read_byte)
+ return -ENOSYS;
+
+ return ops->read_byte(bus);
+}
+
+int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count)
+{
+ int i, ret;
+
+ for (i = 0; i < count; i++) {
+ ret = w1_read_byte(dev);
+ if (ret < 0)
+ return ret;
+
+ buf[i] = ret & 0xff;
+ }
+
+ return 0;
+}
+
+int w1_write_byte(struct udevice *dev, u8 byte)
+{
+ struct udevice *bus = dev_get_parent(dev);
+ const struct w1_ops *ops = device_get_ops(bus);
+
+ if (!ops->write_byte)
+ return -ENOSYS;
+
+ ops->write_byte(bus, byte);
+
+ return 0;
+}
+
+static int w1_post_probe(struct udevice *bus)
+{
+ w1_enumerate(bus);
+
+ return 0;
+}
+
+int w1_init(void)
+{
+ struct udevice *bus;
+ struct uclass *uc;
+ int ret;
+
+ ret = uclass_get(UCLASS_W1, &uc);
+ if (ret)
+ return ret;
+
+ uclass_foreach_dev(bus, uc) {
+ ret = device_probe(bus);
+ if (ret == -ENODEV) { /* No such device. */
+ printf("W1 controller not available.\n");
+ continue;
+ }
+
+ if (ret) { /* Other error. */
+ printf("W1 controller probe failed.\n");
+ continue;
+ }
+ }
+ return 0;
+}
+
+UCLASS_DRIVER(w1) = {
+ .name = "w1",
+ .id = UCLASS_W1,
+ .flags = DM_UC_FLAG_SEQ_ALIAS,
+ .per_device_auto_alloc_size = sizeof(struct w1_bus),
+ .post_probe = w1_post_probe,
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+ .post_bind = dm_scan_fdt_dev,
+#endif
+ .per_child_platdata_auto_alloc_size = sizeof(struct w1_device),
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 7027ea0..fa72afb 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -92,6 +92,7 @@ enum uclass_id {
UCLASS_VIDEO, /* Video or LCD device */
UCLASS_VIDEO_BRIDGE, /* Video bridge, e.g. DisplayPort to LVDS */
UCLASS_VIDEO_CONSOLE, /* Text console driver for video device */
+ UCLASS_W1, /* Dallas 1-Wire bus */
UCLASS_WDT, /* Watchdot Timer driver */

UCLASS_COUNT,
diff --git a/include/w1.h b/include/w1.h
new file mode 100644
index 0000000..b36e0f8
--- /dev/null
+++ b/include/w1.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co
+ *
+ */
+
+#ifndef __W1_H
+#define __W1_H
+
+#include <dm.h>
+
+#define W1_FAMILY_DS24B33 0x23
+#define W1_FAMILY_DS2431 0x2d
+
+struct w1_device {
+ u64 id;
+};
+
+struct w1_ops {
+ u8 (*read_byte)(struct udevice *dev);
+ bool (*reset)(struct udevice *dev);
+ u8 (*triplet)(struct udevice *dev, bool bdir);
+ void (*write_byte)(struct udevice *dev, u8 byte);
+};
+
+int w1_get_bus(int busnum, struct udevice **busp);
+u8 w1_get_device_family(struct udevice *dev);
+
+int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count);
+int w1_read_byte(struct udevice *dev);
+int w1_reset_select(struct udevice *dev);
+int w1_write_buf(struct udevice *dev, u8 *buf, unsigned int count);
+int w1_write_byte(struct udevice *dev, u8 byte);
+
+#endif
--
2.7.4