[PATCH v2] w1: masters: omap_hdq: Add support for 1-wire mode

From: Vignesh R
Date: Mon May 18 2015 - 08:21:06 EST

This patches makes following changes to omap_hdq driver
- Enable 1-wire mode.
- Implement w1_triplet callback to facilitate search rom
procedure and auto detection of 1-wire slaves.
- Proper enabling and disabling of interrupt.
- Cleanups (formatting and return value checks).

HDQ mode remains unchanged.

Signed-off-by: Vignesh R <vigneshr@xxxxxx>
---

v2:
* report error if RX/TX_COMPLETE times out.

Documentation/devicetree/bindings/w1/omap-hdq.txt | 7 +-
Documentation/w1/masters/omap-hdq | 6 +
drivers/w1/masters/omap_hdq.c | 224 ++++++++++++++++++----
3 files changed, 203 insertions(+), 34 deletions(-)

diff --git a/Documentation/devicetree/bindings/w1/omap-hdq.txt b/Documentation/devicetree/bindings/w1/omap-hdq.txt
index fef794741bd1..913c5f91a0f9 100644
--- a/Documentation/devicetree/bindings/w1/omap-hdq.txt
+++ b/Documentation/devicetree/bindings/w1/omap-hdq.txt
@@ -1,11 +1,15 @@
* OMAP HDQ One wire bus master controller

Required properties:
-- compatible : should be "ti,omap3-1w"
+- compatible : should be "ti,omap3-1w" or "ti,am4372-hdq"
- reg : Address and length of the register set for the device
- interrupts : interrupt line.
- ti,hwmods : "hdq1w"

+Optional properties:
+- ti,mode: should be "hdq": HDQ mode "1w": one-wire mode.
+ If not specified HDQ mode is implied.
+
Example:

- From omap3.dtsi
@@ -14,4 +18,5 @@ Example:
reg = <0x480b2000 0x1000>;
interrupts = <58>;
ti,hwmods = "hdq1w";
+ ti,mode = "hdq";
};
diff --git a/Documentation/w1/masters/omap-hdq b/Documentation/w1/masters/omap-hdq
index 884dc284b215..234522709a5f 100644
--- a/Documentation/w1/masters/omap-hdq
+++ b/Documentation/w1/masters/omap-hdq
@@ -44,3 +44,9 @@ e.g:
insmod omap_hdq.ko W1_ID=2
inamod w1_bq27000.ko F_ID=2

+The driver also supports 1-wire mode. In this mode, there is no need to
+pass slave ID as parameter. The driver will auto-detect slaves connected
+to the bus using SEARCH_ROM procedure. 1-wire mode can be selected by
+setting "ti,mode" property to "1w" in DT (see
+Documentation/devicetree/bindings/w1/omap-hdq.txt for more details).
+By default driver is in HDQ mode.
diff --git a/drivers/w1/masters/omap_hdq.c b/drivers/w1/masters/omap_hdq.c
index e7d448963a24..0e2f43bccf1f 100644
--- a/drivers/w1/masters/omap_hdq.c
+++ b/drivers/w1/masters/omap_hdq.c
@@ -17,6 +17,7 @@
#include <linux/io.h>
#include <linux/sched.h>
#include <linux/pm_runtime.h>
+#include <linux/of.h>

#include "../w1.h"
#include "../w1_int.h"
@@ -27,21 +28,23 @@
#define OMAP_HDQ_TX_DATA 0x04
#define OMAP_HDQ_RX_DATA 0x08
#define OMAP_HDQ_CTRL_STATUS 0x0c
-#define OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK (1<<6)
-#define OMAP_HDQ_CTRL_STATUS_CLOCKENABLE (1<<5)
-#define OMAP_HDQ_CTRL_STATUS_GO (1<<4)
-#define OMAP_HDQ_CTRL_STATUS_INITIALIZATION (1<<2)
-#define OMAP_HDQ_CTRL_STATUS_DIR (1<<1)
-#define OMAP_HDQ_CTRL_STATUS_MODE (1<<0)
+#define OMAP_HDQ_CTRL_STATUS_SINGLE BIT(7)
+#define OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK BIT(6)
+#define OMAP_HDQ_CTRL_STATUS_CLOCKENABLE BIT(5)
+#define OMAP_HDQ_CTRL_STATUS_GO BIT(4)
+#define OMAP_HDQ_CTRL_STATUS_PRESENCE BIT(3)
+#define OMAP_HDQ_CTRL_STATUS_INITIALIZATION BIT(2)
+#define OMAP_HDQ_CTRL_STATUS_DIR BIT(1)
#define OMAP_HDQ_INT_STATUS 0x10
-#define OMAP_HDQ_INT_STATUS_TXCOMPLETE (1<<2)
-#define OMAP_HDQ_INT_STATUS_RXCOMPLETE (1<<1)
-#define OMAP_HDQ_INT_STATUS_TIMEOUT (1<<0)
+#define OMAP_HDQ_INT_STATUS_TXCOMPLETE BIT(2)
+#define OMAP_HDQ_INT_STATUS_RXCOMPLETE BIT(1)
+#define OMAP_HDQ_INT_STATUS_TIMEOUT BIT(0)
#define OMAP_HDQ_SYSCONFIG 0x14
-#define OMAP_HDQ_SYSCONFIG_SOFTRESET (1<<1)
-#define OMAP_HDQ_SYSCONFIG_AUTOIDLE (1<<0)
+#define OMAP_HDQ_SYSCONFIG_SOFTRESET BIT(1)
+#define OMAP_HDQ_SYSCONFIG_AUTOIDLE BIT(0)
+#define OMAP_HDQ_SYSCONFIG_NOIDLE 0x0
#define OMAP_HDQ_SYSSTATUS 0x18
-#define OMAP_HDQ_SYSSTATUS_RESETDONE (1<<0)
+#define OMAP_HDQ_SYSSTATUS_RESETDONE BIT(0)

#define OMAP_HDQ_FLAG_CLEAR 0
#define OMAP_HDQ_FLAG_SET 1
@@ -67,6 +70,10 @@ struct hdq_data {
* the data wrire or read.
*/
int init_trans;
+ int rrw;
+ /* mode: 0-HDQ 1-W1 */
+ int mode;
+
};

static int omap_hdq_probe(struct platform_device *pdev);
@@ -74,6 +81,7 @@ static int omap_hdq_remove(struct platform_device *pdev);

static const struct of_device_id omap_hdq_dt_ids[] = {
{ .compatible = "ti,omap3-1w" },
+ { .compatible = "ti,am4372-hdq" },
{}
};
MODULE_DEVICE_TABLE(of, omap_hdq_dt_ids);
@@ -90,15 +98,12 @@ static struct platform_driver omap_hdq_driver = {
static u8 omap_w1_read_byte(void *_hdq);
static void omap_w1_write_byte(void *_hdq, u8 byte);
static u8 omap_w1_reset_bus(void *_hdq);
-static void omap_w1_search_bus(void *_hdq, struct w1_master *master_dev,
- u8 search_type, w1_slave_found_callback slave_found);


static struct w1_bus_master omap_w1_master = {
.read_byte = omap_w1_read_byte,
.write_byte = omap_w1_write_byte,
.reset_bus = omap_w1_reset_bus,
- .search = omap_w1_search_bus,
};

/* HDQ register I/O routines */
@@ -122,6 +127,15 @@ static inline u8 hdq_reg_merge(struct hdq_data *hdq_data, u32 offset,
return new_val;
}

+static void hdq_disable_interrupt(struct hdq_data *hdq_data, u32 offset,
+ u32 mask)
+{
+ u32 ie;
+
+ ie = readl(hdq_data->hdq_base + offset);
+ writel(ie & mask, hdq_data->hdq_base + offset);
+}
+
/*
* Wait for one or more bits in flag change.
* HDQ_FLAG_SET: wait until any bit in the flag is set.
@@ -229,13 +243,7 @@ static irqreturn_t hdq_isr(int irq, void *_hdq)
return IRQ_HANDLED;
}

-/* HDQ Mode: always return success */
-static u8 omap_w1_reset_bus(void *_hdq)
-{
- return 0;
-}
-
-/* W1 search callback function */
+/* W1 search callback function in HDQ mode */
static void omap_w1_search_bus(void *_hdq, struct w1_master *master_dev,
u8 search_type, w1_slave_found_callback slave_found)
{
@@ -262,9 +270,10 @@ static int _omap_hdq_reset(struct hdq_data *hdq_data)
int ret;
u8 tmp_status;

- hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG, OMAP_HDQ_SYSCONFIG_SOFTRESET);
+ hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
+ OMAP_HDQ_SYSCONFIG_SOFTRESET);
/*
- * Select HDQ mode & enable clocks.
+ * Select HDQ/1W mode & enable clocks.
* It is observed that INT flags can't be cleared via a read and GO/INIT
* won't return to zero if interrupt is disabled. So we always enable
* interrupt.
@@ -282,7 +291,8 @@ static int _omap_hdq_reset(struct hdq_data *hdq_data)
else {
hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
- OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
+ OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK |
+ hdq_data->mode);
hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
OMAP_HDQ_SYSCONFIG_AUTOIDLE);
}
@@ -334,6 +344,18 @@ static int omap_hdq_break(struct hdq_data *hdq_data)
ret = -ETIMEDOUT;
goto out;
}
+
+ /*
+ * check for the presence detect bit to get
+ * set to show that the slave is responding
+ */
+ if (!(hdq_reg_in(hdq_data, OMAP_HDQ_CTRL_STATUS) &
+ OMAP_HDQ_CTRL_STATUS_PRESENCE)) {
+ dev_dbg(hdq_data->dev, "Presence bit not set\n");
+ ret = -ETIMEDOUT;
+ goto out;
+ }
+
/*
* wait for both INIT and GO bits rerurn to zero.
* zero wait time expected for interrupt mode.
@@ -368,6 +390,8 @@ static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
goto out;
}

+ hdq_data->hdq_irqstatus = 0;
+
if (!(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO,
@@ -400,7 +424,7 @@ rtn:

}

-/* Enable clocks and set the controller to HDQ mode */
+/* Enable clocks and set the controller to HDQ/1W mode */
static int omap_hdq_get(struct hdq_data *hdq_data)
{
int ret = 0;
@@ -422,7 +446,7 @@ static int omap_hdq_get(struct hdq_data *hdq_data)

pm_runtime_get_sync(hdq_data->dev);

- /* make sure HDQ is out of reset */
+ /* make sure HDQ/1W is out of reset */
if (!(hdq_reg_in(hdq_data, OMAP_HDQ_SYSSTATUS) &
OMAP_HDQ_SYSSTATUS_RESETDONE)) {
ret = _omap_hdq_reset(hdq_data);
@@ -430,12 +454,13 @@ static int omap_hdq_get(struct hdq_data *hdq_data)
/* back up the count */
hdq_data->hdq_usecount--;
} else {
- /* select HDQ mode & enable clocks */
+ /* select HDQ/1W mode & enable clocks */
hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
- OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
+ OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK |
+ hdq_data->mode);
hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
- OMAP_HDQ_SYSCONFIG_AUTOIDLE);
+ OMAP_HDQ_SYSCONFIG_NOIDLE);
hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
}
}
@@ -456,6 +481,8 @@ static int omap_hdq_put(struct hdq_data *hdq_data)
if (ret < 0)
return -EINTR;

+ hdq_reg_out(hdq_data, OMAP_HDQ_SYSCONFIG,
+ OMAP_HDQ_SYSCONFIG_AUTOIDLE);
if (0 == hdq_data->hdq_usecount) {
dev_dbg(hdq_data->dev, "attempt to decrement use count"
" when it is zero");
@@ -471,6 +498,100 @@ static int omap_hdq_put(struct hdq_data *hdq_data)
return ret;
}

+/*
+ * W1 triplet callback function - used for searching ROM addresses.
+ * Registered only when controller is in 1-wire mode.
+ */
+static u8 omap_w1_triplet(void *_hdq, u8 bdir)
+{
+ u8 id_bit, comp_bit;
+ int err;
+ u8 ret = 0x3; /* no slaves responded */
+ struct hdq_data *hdq_data = _hdq;
+ u8 ctrl = OMAP_HDQ_CTRL_STATUS_SINGLE | OMAP_HDQ_CTRL_STATUS_GO |
+ OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK;
+ u8 mask = ctrl | OMAP_HDQ_CTRL_STATUS_DIR;
+
+ omap_hdq_get(_hdq);
+
+ err = mutex_lock_interruptible(&hdq_data->hdq_mutex);
+ if (err < 0) {
+ dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
+ goto rtn;
+ }
+
+ hdq_data->hdq_irqstatus = 0;
+ /* read id_bit */
+ hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
+ ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
+ err = wait_event_timeout(hdq_wait_queue,
+ (hdq_data->hdq_irqstatus
+ & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
+ OMAP_HDQ_TIMEOUT);
+ if (err == 0) {
+ dev_dbg(hdq_data->dev, "RX wait elapsed\n");
+ goto out;
+ }
+ id_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
+
+ hdq_data->hdq_irqstatus = 0;
+ /* read comp_bit */
+ hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
+ ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
+ err = wait_event_timeout(hdq_wait_queue,
+ (hdq_data->hdq_irqstatus
+ & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
+ OMAP_HDQ_TIMEOUT);
+ if (err == 0) {
+ dev_dbg(hdq_data->dev, "RX wait elapsed\n");
+ goto out;
+ }
+ comp_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
+
+ if (id_bit && comp_bit) {
+ ret = 0x03; /* no slaves responded */
+ goto out;
+ }
+ if (!id_bit && !comp_bit) {
+ /* Both bits are valid, take the direction given */
+ ret = bdir ? 0x04 : 0;
+ } else {
+ /* Only one bit is valid, take that direction */
+ bdir = id_bit;
+ ret = id_bit ? 0x05 : 0x02;
+ }
+
+ /* write bdir bit */
+ hdq_reg_out(_hdq, OMAP_HDQ_TX_DATA, bdir);
+ hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, ctrl, mask);
+ err = wait_event_timeout(hdq_wait_queue,
+ (hdq_data->hdq_irqstatus
+ & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
+ OMAP_HDQ_TIMEOUT);
+ if (err == 0) {
+ dev_dbg(hdq_data->dev, "TX wait elapsed\n");
+ goto out;
+ }
+
+ hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, 0,
+ OMAP_HDQ_CTRL_STATUS_SINGLE);
+
+out:
+ mutex_unlock(&hdq_data->hdq_mutex);
+rtn:
+ omap_hdq_put(_hdq);
+ return ret;
+}
+
+/* reset callback */
+static u8 omap_w1_reset_bus(void *_hdq)
+{
+ omap_hdq_get(_hdq);
+ omap_hdq_break(_hdq);
+ omap_hdq_put(_hdq);
+ return 0;
+}
+
/* Read a byte of data from the device */
static u8 omap_w1_read_byte(void *_hdq)
{
@@ -478,6 +599,10 @@ static u8 omap_w1_read_byte(void *_hdq)
u8 val = 0;
int ret;

+ /* First write to initialize the transfer */
+ if (hdq_data->init_trans == 0)
+ omap_hdq_get(hdq_data);
+
ret = hdq_read_byte(hdq_data, &val);
if (ret) {
ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
@@ -491,6 +616,10 @@ static u8 omap_w1_read_byte(void *_hdq)
return -1;
}

+ hdq_disable_interrupt(hdq_data, OMAP_HDQ_CTRL_STATUS,
+ ~OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK);
+ hdq_data->hdq_usecount = 0;
+
/* Write followed by a read, release the module */
if (hdq_data->init_trans) {
ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
@@ -517,6 +646,14 @@ static void omap_w1_write_byte(void *_hdq, u8 byte)
if (hdq_data->init_trans == 0)
omap_hdq_get(hdq_data);

+ /*
+ * We need to reset the slave before
+ * issuing the SKIP ROM command, else
+ * the slave will not work.
+ */
+ if (byte == W1_SKIP_ROM)
+ omap_hdq_break(hdq_data);
+
ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
if (ret < 0) {
dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
@@ -551,6 +688,7 @@ static int omap_hdq_probe(struct platform_device *pdev)
struct resource *res;
int ret, irq;
u8 rev;
+ const char *mode;

hdq_data = devm_kzalloc(dev, sizeof(*hdq_data), GFP_KERNEL);
if (!hdq_data) {
@@ -567,10 +705,21 @@ static int omap_hdq_probe(struct platform_device *pdev)
return PTR_ERR(hdq_data->hdq_base);

hdq_data->hdq_usecount = 0;
+ hdq_data->rrw = 0;
mutex_init(&hdq_data->hdq_mutex);

pm_runtime_enable(&pdev->dev);
- pm_runtime_get_sync(&pdev->dev);
+ ret = pm_runtime_get_sync(&pdev->dev);
+ if (ret < 0) {
+ dev_dbg(&pdev->dev, "pm_runtime_get_sync failed\n");
+ goto err_w1;
+ }
+
+ ret = _omap_hdq_reset(hdq_data);
+ if (ret) {
+ dev_dbg(&pdev->dev, "reset failed\n");
+ return -EINVAL;
+ }

rev = hdq_reg_in(hdq_data, OMAP_HDQ_REVISION);
dev_info(&pdev->dev, "OMAP HDQ Hardware Rev %c.%c. Driver in %s mode\n",
@@ -594,6 +743,15 @@ static int omap_hdq_probe(struct platform_device *pdev)

pm_runtime_put_sync(&pdev->dev);

+ ret = of_property_read_string(pdev->dev.of_node, "ti,mode", &mode);
+ if (ret < 0 || !strcmp(mode, "hdq")) {
+ hdq_data->mode = 0;
+ omap_w1_master.search = omap_w1_search_bus;
+ } else {
+ hdq_data->mode = 1;
+ omap_w1_master.triplet = omap_w1_triplet;
+ }
+
omap_w1_master.data = hdq_data;

ret = w1_add_master_device(&omap_w1_master);
@@ -635,8 +793,8 @@ static int omap_hdq_remove(struct platform_device *pdev)
module_platform_driver(omap_hdq_driver);

module_param(w1_id, int, S_IRUSR);
-MODULE_PARM_DESC(w1_id, "1-wire id for the slave detection");
+MODULE_PARM_DESC(w1_id, "1-wire id for the slave detection in HDQ mode");

MODULE_AUTHOR("Texas Instruments");
-MODULE_DESCRIPTION("HDQ driver Library");
+MODULE_DESCRIPTION("HDQ-1W driver Library");
MODULE_LICENSE("GPL");
--
1.9.1

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