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authorAngelos Mouzakitis <a.mouzakitis@virtualopensystems.com>2023-10-10 14:33:42 +0000
committerAngelos Mouzakitis <a.mouzakitis@virtualopensystems.com>2023-10-10 14:33:42 +0000
commitaf1a266670d040d2f4083ff309d732d648afba2a (patch)
tree2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/u-boot/drivers/w1
parente02cda008591317b1625707ff8e115a4841aa889 (diff)
Add submodule dependency filesHEADmaster
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/u-boot/drivers/w1')
-rw-r--r--roms/u-boot/drivers/w1/Kconfig39
-rw-r--r--roms/u-boot/drivers/w1/Makefile4
-rw-r--r--roms/u-boot/drivers/w1/mxc_w1.c235
-rw-r--r--roms/u-boot/drivers/w1/w1-gpio.c178
-rw-r--r--roms/u-boot/drivers/w1/w1-uclass.c311
5 files changed, 767 insertions, 0 deletions
diff --git a/roms/u-boot/drivers/w1/Kconfig b/roms/u-boot/drivers/w1/Kconfig
new file mode 100644
index 000000000..031bab25a
--- /dev/null
+++ b/roms/u-boot/drivers/w1/Kconfig
@@ -0,0 +1,39 @@
+#
+# 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
+
+config W1_GPIO
+ bool "Enable 1-wire GPIO bitbanging"
+ default no
+ depends on DM_GPIO
+ help
+ Emulate a 1-wire bus using a GPIO.
+
+config W1_MXC
+ bool "Enable 1-wire controller on i.MX processors"
+ default no
+ depends on ARCH_MX25 || ARCH_MX31 || ARCH_MX5
+ help
+ Support the one wire controller found in some members of the NXP
+ i.MX SoC family.
+ There are currently two silicon variants:
+ V1: i.MX21, i.MX27, i.MX31, i.MX51
+ V2: i.MX25, i.MX35, i.MX50, i.MX53
+ Newer i.MX SoCs such as the i.MX6 do not have one wire controllers.
+
+ The driver supports both silicon variants.
+
+endif
+
+endmenu
diff --git a/roms/u-boot/drivers/w1/Makefile b/roms/u-boot/drivers/w1/Makefile
new file mode 100644
index 000000000..9825187b6
--- /dev/null
+++ b/roms/u-boot/drivers/w1/Makefile
@@ -0,0 +1,4 @@
+obj-$(CONFIG_W1) += w1-uclass.o
+
+obj-$(CONFIG_W1_GPIO) += w1-gpio.o
+obj-$(CONFIG_W1_MXC) += mxc_w1.o
diff --git a/roms/u-boot/drivers/w1/mxc_w1.c b/roms/u-boot/drivers/w1/mxc_w1.c
new file mode 100644
index 000000000..b96c1a00b
--- /dev/null
+++ b/roms/u-boot/drivers/w1/mxc_w1.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for one wire controller in some i.MX Socs
+ *
+ * There are currently two silicon variants:
+ * V1: i.MX21, i.MX27, i.MX31, i.MX51
+ * V2: i.MX25, i.MX35, i.MX50, i.MX53
+ * Newer i.MX SoCs such as the i.MX6 do not have one wire controllers.
+ *
+ * The V1 controller only supports single bit operations.
+ * The V2 controller is backwards compatible on the register level but adds
+ * byte size operations and a "search ROM accelerator mode"
+ *
+ * This driver does not currently support the search ROM accelerator
+ *
+ * Copyright (c) 2018 Flowbird
+ * Martin Fuzzey <martin.fuzzey@flowbird.group>
+ */
+
+#include <common.h>
+#include <asm/arch/clock.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <w1.h>
+
+struct mxc_w1_regs {
+ u16 control;
+#define MXC_W1_CONTROL_RPP BIT(7)
+#define MXC_W1_CONTROL_PST BIT(6)
+#define MXC_W1_CONTROL_WR(x) BIT(5 - (x))
+#define MXC_W1_CONTROL_RDST BIT(3)
+
+ u16 time_divider;
+ u16 reset;
+
+ /* Registers below on V2 silicon only */
+ u16 command;
+ u16 tx_rx;
+ u16 interrupt;
+#define MXC_W1_INTERRUPT_TBE BIT(2)
+#define MXC_W1_INTERRUPT_TSRE BIT(3)
+#define MXC_W1_INTERRUPT_RBF BIT(4)
+#define MXC_W1_INTERRUPT_RSRF BIT(5)
+
+ u16 interrupt_en;
+};
+
+struct mxc_w1_pdata {
+ struct mxc_w1_regs *regs;
+};
+
+/*
+ * 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_touch_bit(struct mxc_w1_pdata *pdata, u8 bit)
+{
+ u16 *ctrl_addr = &pdata->regs->control;
+ u16 mask = MXC_W1_CONTROL_WR(bit);
+ unsigned int timeout_cnt = 400; /* Takes max. 120us according to
+ * datasheet.
+ */
+
+ writew(mask, ctrl_addr);
+
+ while (timeout_cnt--) {
+ if (!(readw(ctrl_addr) & mask))
+ break;
+
+ udelay(1);
+ }
+
+ return (readw(ctrl_addr) & MXC_W1_CONTROL_RDST) ? 1 : 0;
+}
+
+static u8 mxc_w1_read_byte(struct udevice *dev)
+{
+ struct mxc_w1_pdata *pdata = dev_get_plat(dev);
+ struct mxc_w1_regs *regs = pdata->regs;
+ u16 status;
+
+ if (dev_get_driver_data(dev) < 2) {
+ int i;
+ u8 ret = 0;
+
+ for (i = 0; i < 8; i++)
+ ret |= (mxc_w1_touch_bit(pdata, 1) << i);
+
+ return ret;
+ }
+
+ readw(&regs->tx_rx);
+ writew(0xFF, &regs->tx_rx);
+
+ do {
+ udelay(1); /* Without this bytes are sometimes duplicated... */
+ status = readw(&regs->interrupt);
+ } while (!(status & MXC_W1_INTERRUPT_RBF));
+
+ return (u8)readw(&regs->tx_rx);
+}
+
+static void mxc_w1_write_byte(struct udevice *dev, u8 byte)
+{
+ struct mxc_w1_pdata *pdata = dev_get_plat(dev);
+ struct mxc_w1_regs *regs = pdata->regs;
+ u16 status;
+
+ if (dev_get_driver_data(dev) < 2) {
+ int i;
+
+ for (i = 0; i < 8; i++)
+ mxc_w1_touch_bit(pdata, (byte >> i) & 0x1);
+
+ return;
+ }
+
+ readw(&regs->tx_rx);
+ writew(byte, &regs->tx_rx);
+
+ do {
+ udelay(1);
+ status = readw(&regs->interrupt);
+ } while (!(status & MXC_W1_INTERRUPT_TSRE));
+}
+
+static bool mxc_w1_reset(struct udevice *dev)
+{
+ struct mxc_w1_pdata *pdata = dev_get_plat(dev);
+ u16 reg_val;
+
+ writew(MXC_W1_CONTROL_RPP, &pdata->regs->control);
+
+ do {
+ reg_val = readw(&pdata->regs->control);
+ } while (reg_val & MXC_W1_CONTROL_RPP);
+
+ return !(reg_val & MXC_W1_CONTROL_PST);
+}
+
+static u8 mxc_w1_triplet(struct udevice *dev, bool bdir)
+{
+ struct mxc_w1_pdata *pdata = dev_get_plat(dev);
+ u8 id_bit = mxc_w1_touch_bit(pdata, 1);
+ u8 comp_bit = mxc_w1_touch_bit(pdata, 1);
+ u8 retval;
+
+ if (id_bit && comp_bit)
+ return 0x03; /* error */
+
+ if (!id_bit && !comp_bit) {
+ /* Both bits are valid, take the direction given */
+ retval = bdir ? 0x04 : 0;
+ } else {
+ /* Only one bit is valid, take that direction */
+ bdir = id_bit;
+ retval = id_bit ? 0x05 : 0x02;
+ }
+
+ mxc_w1_touch_bit(pdata, bdir);
+
+ return retval;
+}
+
+static int mxc_w1_of_to_plat(struct udevice *dev)
+{
+ struct mxc_w1_pdata *pdata = dev_get_plat(dev);
+ fdt_addr_t addr;
+
+ addr = dev_read_addr(dev);
+ if (addr == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ pdata->regs = (struct mxc_w1_regs *)addr;
+
+ return 0;
+};
+
+static int mxc_w1_probe(struct udevice *dev)
+{
+ struct mxc_w1_pdata *pdata = dev_get_plat(dev);
+ unsigned int clkrate = mxc_get_clock(MXC_IPG_PERCLK);
+ unsigned int clkdiv;
+
+ if (clkrate < 10000000) {
+ dev_err(dev, "input clock frequency (%u Hz) too low\n",
+ clkrate);
+ return -EINVAL;
+ }
+
+ clkdiv = clkrate / 1000000;
+ clkrate /= clkdiv;
+ if (clkrate < 980000 || clkrate > 1020000) {
+ dev_err(dev, "Incorrect time base frequency %u Hz\n", clkrate);
+ return -EINVAL;
+ }
+
+ writew(clkdiv - 1, &pdata->regs->time_divider);
+
+ return 0;
+}
+
+static const struct w1_ops mxc_w1_ops = {
+ .read_byte = mxc_w1_read_byte,
+ .reset = mxc_w1_reset,
+ .triplet = mxc_w1_triplet,
+ .write_byte = mxc_w1_write_byte,
+};
+
+static const struct udevice_id mxc_w1_id[] = {
+ { .compatible = "fsl,imx21-owire", .data = 1 },
+ { .compatible = "fsl,imx27-owire", .data = 1 },
+ { .compatible = "fsl,imx31-owire", .data = 1 },
+ { .compatible = "fsl,imx51-owire", .data = 1 },
+
+ { .compatible = "fsl,imx25-owire", .data = 2 },
+ { .compatible = "fsl,imx35-owire", .data = 2 },
+ { .compatible = "fsl,imx50-owire", .data = 2 },
+ { .compatible = "fsl,imx53-owire", .data = 2 },
+ { },
+};
+
+U_BOOT_DRIVER(mxc_w1_drv) = {
+ .id = UCLASS_W1,
+ .name = "mxc_w1_drv",
+ .of_match = mxc_w1_id,
+ .of_to_plat = mxc_w1_of_to_plat,
+ .ops = &mxc_w1_ops,
+ .plat_auto = sizeof(struct mxc_w1_pdata),
+ .probe = mxc_w1_probe,
+};
diff --git a/roms/u-boot/drivers/w1/w1-gpio.c b/roms/u-boot/drivers/w1/w1-gpio.c
new file mode 100644
index 000000000..3b0ead6f6
--- /dev/null
+++ b/roms/u-boot/drivers/w1/w1-gpio.c
@@ -0,0 +1,178 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <log.h>
+#include <w1.h>
+#include <linux/delay.h>
+
+#include <asm/gpio.h>
+
+#define W1_TIMING_A 6
+#define W1_TIMING_B 64
+#define W1_TIMING_C 60
+#define W1_TIMING_D 10
+#define W1_TIMING_E 9
+#define W1_TIMING_F 55
+#define W1_TIMING_G 0
+#define W1_TIMING_H 480
+#define W1_TIMING_I 70
+#define W1_TIMING_J 410
+
+struct w1_gpio_pdata {
+ struct gpio_desc gpio;
+ u64 search_id;
+};
+
+static bool w1_gpio_read_bit(struct udevice *dev)
+{
+ struct w1_gpio_pdata *pdata = dev_get_plat(dev);
+ int val;
+
+ dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT);
+ udelay(W1_TIMING_A);
+
+ dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_IN);
+ udelay(W1_TIMING_E);
+
+ val = dm_gpio_get_value(&pdata->gpio);
+ if (val < 0)
+ debug("error in retrieving GPIO value");
+ udelay(W1_TIMING_F);
+
+ return val;
+}
+
+static u8 w1_gpio_read_byte(struct udevice *dev)
+{
+ int i;
+ u8 ret = 0;
+
+ for (i = 0; i < 8; ++i)
+ ret |= (w1_gpio_read_bit(dev) ? 1 : 0) << i;
+
+ return ret;
+}
+
+static void w1_gpio_write_bit(struct udevice *dev, bool bit)
+{
+ struct w1_gpio_pdata *pdata = dev_get_plat(dev);
+
+ dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT);
+
+ bit ? udelay(W1_TIMING_A) : udelay(W1_TIMING_C);
+
+ dm_gpio_set_value(&pdata->gpio, 1);
+
+ bit ? udelay(W1_TIMING_B) : udelay(W1_TIMING_D);
+}
+
+static void w1_gpio_write_byte(struct udevice *dev, u8 byte)
+{
+ int i;
+
+ for (i = 0; i < 8; ++i)
+ w1_gpio_write_bit(dev, (byte >> i) & 0x1);
+}
+
+static bool w1_gpio_reset(struct udevice *dev)
+{
+ struct w1_gpio_pdata *pdata = dev_get_plat(dev);
+ int val;
+
+ /* initiate the reset pulse. first we must pull the bus to low */
+ dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
+ udelay(W1_TIMING_G);
+
+ dm_gpio_set_value(&pdata->gpio, 0);
+ /* wait for the specified time with the bus kept low */
+ udelay(W1_TIMING_H);
+
+ /* now we must read the presence pulse */
+ dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_IN);
+ udelay(W1_TIMING_I);
+
+ val = dm_gpio_get_value(&pdata->gpio);
+ if (val < 0)
+ debug("error in retrieving GPIO value");
+
+ /* if nobody pulled the bus down , it means nobody is on the bus */
+ if (val != 0)
+ return 1;
+ /* we have the bus pulled down, let's wait for the specified presence time */
+ udelay(W1_TIMING_J);
+
+ /* read again, the other end should leave the bus free */
+ val = dm_gpio_get_value(&pdata->gpio);
+ if (val < 0)
+ debug("error in retrieving GPIO value");
+
+ /* bus is not going up again, so we have an error */
+ if (val != 1)
+ return 1;
+
+ /* all good, presence detected */
+ return 0;
+}
+
+static u8 w1_gpio_triplet(struct udevice *dev, bool bdir)
+{
+ u8 id_bit = w1_gpio_read_bit(dev);
+ u8 comp_bit = w1_gpio_read_bit(dev);
+ u8 retval;
+
+ if (id_bit && comp_bit)
+ return 0x03; /* error */
+
+ if (!id_bit && !comp_bit) {
+ /* Both bits are valid, take the direction given */
+ retval = bdir ? 0x04 : 0;
+ } else {
+ /* Only one bit is valid, take that direction */
+ bdir = id_bit;
+ retval = id_bit ? 0x05 : 0x02;
+ }
+
+ w1_gpio_write_bit(dev, bdir);
+ return retval;
+}
+
+static const struct w1_ops w1_gpio_ops = {
+ .read_byte = w1_gpio_read_byte,
+ .reset = w1_gpio_reset,
+ .triplet = w1_gpio_triplet,
+ .write_byte = w1_gpio_write_byte,
+};
+
+static int w1_gpio_of_to_plat(struct udevice *dev)
+{
+ struct w1_gpio_pdata *pdata = dev_get_plat(dev);
+ int ret;
+
+ ret = gpio_request_by_name(dev, "gpios", 0, &pdata->gpio, 0);
+ if (ret < 0)
+ printf("Error claiming GPIO %d\n", ret);
+
+ return ret;
+};
+
+static const struct udevice_id w1_gpio_id[] = {
+ { "w1-gpio", 0 },
+ { },
+};
+
+U_BOOT_DRIVER(w1_gpio_drv) = {
+ .id = UCLASS_W1,
+ .name = "w1_gpio_drv",
+ .of_match = w1_gpio_id,
+ .of_to_plat = w1_gpio_of_to_plat,
+ .ops = &w1_gpio_ops,
+ .plat_auto = sizeof(struct w1_gpio_pdata),
+};
diff --git a/roms/u-boot/drivers/w1/w1-uclass.c b/roms/u-boot/drivers/w1/w1-uclass.c
new file mode 100644
index 000000000..b98927389
--- /dev/null
+++ b/roms/u-boot/drivers/w1/w1-uclass.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co.
+ * Copyright (c) 2018 Microchip Technology, Inc.
+ * Copyright (c) 2021 Bootlin
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ * Eugen Hristev <eugen.hristev@microchip.com>
+ * Kory Maincent <kory.maincent@bootlin.com>
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <log.h>
+#include <w1.h>
+#include <w1-eeprom.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;
+};
+
+int w1_bus_find_dev(const struct udevice *bus, u64 id, struct udevice
+**devp)
+{
+ struct udevice *dev;
+ u8 family = id & 0xff;
+ int ret;
+
+ for (ret = uclass_first_device(UCLASS_W1_EEPROM, &dev);
+ !ret && dev;
+ uclass_next_device(&dev)) {
+ if (ret || !dev) {
+ debug("cannot find w1 eeprom dev\n");
+ return -ENODEV;
+ }
+
+ if (dev_get_driver_data(dev) == family) {
+ *devp = dev;
+ return 0;
+ }
+ }
+
+ return -ENODEV;
+}
+
+int w1_register_new_device(u64 id, struct udevice *bus)
+{
+ u8 family = id & 0xff;
+ int n_ents, ret = 0;
+ struct udevice *dev;
+
+ struct w1_driver_entry *start, *entry;
+
+ start = ll_entry_start(struct w1_driver_entry, w1_driver_entry);
+ n_ents = ll_entry_count(struct w1_driver_entry, w1_driver_entry);
+
+ for (entry = start; entry != start + n_ents; entry++) {
+ const u8 *match_family;
+ const struct driver *drv;
+ struct w1_device *w1;
+
+ for (match_family = entry->family; match_family;
+ match_family++) {
+ if (*match_family != family)
+ continue;
+
+ ret = w1_bus_find_dev(bus, id, &dev);
+
+ /* If nothing in the device tree, bind a device */
+ if (ret == -ENODEV) {
+ drv = entry->driver;
+ ret = device_bind(bus, drv, drv->name,
+ NULL, ofnode_null(), &dev);
+ if (ret)
+ return ret;
+ }
+
+ device_probe(dev);
+
+ w1 = dev_get_parent_plat(dev);
+ w1->id = id;
+
+ return 0;
+ }
+ }
+
+ debug("%s: No matches found: error %d\n", __func__, ret);
+
+ return ret;
+}
+
+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);
+ }
+
+ 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));
+
+ /* attempt to register as w1 device */
+ w1_register_new_device(rn, bus);
+ }
+ }
+
+ 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);
+ dev && !ret;
+ ret = uclass_next_device(&dev), i++) {
+ if (i == busnum) {
+ *busp = dev;
+ return 0;
+ }
+ }
+
+ if (!ret) {
+ debug("Cannot find w1 bus %d\n", busnum);
+ ret = -ENODEV;
+ }
+
+ return ret;
+}
+
+u8 w1_get_device_family(struct udevice *dev)
+{
+ struct w1_device *w1 = dev_get_parent_plat(dev);
+
+ return w1->id & 0xff;
+}
+
+int w1_reset_select(struct udevice *dev)
+{
+ struct w1_device *w1 = dev_get_parent_plat(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 = sizeof(struct w1_bus),
+ .post_probe = w1_post_probe,
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+ .post_bind = dm_scan_fdt_dev,
+#endif
+ .per_child_plat_auto = sizeof(struct w1_device),
+};