[PATCH 0/3] Add parameters to sysfs added i2c devices

[PATCH 0/3] Add parameters to sysfs added i2c devices

[minyard]

When I was testing with qemu, I needed a way to pass in the irq to
the smbus alert handler, and I needed a way to set some IPMI SSIF
parameters.  These patches add a way to pass in parameters to
sysfs, show how the IPMI SSIF driver can use this, and then adds
handling of irq setup for the i2c-smbus alert handler.

-corey

[PATCH 1/3] i2c: Add parameters to sysfs-added i2c devices

[minyard]

From: Corey Minyard <cminyard@mvista.com>

Some devices might need parameters to control their operation,
add the ability to pass these parameters to the client.

This also makes the parsing of sysfs-added I2C devices a little
more flexible, allowing tabs and arbitrary numbers of spaces.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 drivers/i2c/i2c-core.c | 46 ++++++++++++++++++++++++++++++++++------------
 include/linux/i2c.h    |  3 +++
 2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index ffe715d..e2e42fc 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -785,7 +785,10 @@ static void i2c_device_shutdown(struct device *dev)
 
 static void i2c_client_dev_release(struct device *dev)
 {
-	kfree(to_i2c_client(dev));
+	struct i2c_client *client = to_i2c_client(dev);
+
+	kfree(client->parms);
+	kfree(client);
 }
 
 static ssize_t
@@ -1052,6 +1055,13 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 	client->flags = info->flags;
 	client->addr = info->addr;
 	client->irq = info->irq;
+	if (info->parms) {
+		client->parms = kstrdup(info->parms, GFP_KERNEL);
+		if (!client->parms) {
+			dev_err(&adap->dev, "Out of memory allocating parms\n");
+			goto out_err_silent;
+		}
+	}
 
 	strlcpy(client->name, info->type, sizeof(client->name));
 
@@ -1201,31 +1211,43 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 	struct i2c_adapter *adap = to_i2c_adapter(dev);
 	struct i2c_board_info info;
 	struct i2c_client *client;
-	char *blank, end;
+	char *pos, end;
 	int res;
 
 	memset(&info, 0, sizeof(struct i2c_board_info));
 
-	blank = strchr(buf, ' ');
-	if (!blank) {
+	pos = strpbrk(buf, " \t");
+	if (!pos) {
 		dev_err(dev, "%s: Missing parameters\n", "new_device");
 		return -EINVAL;
 	}
-	if (blank - buf > I2C_NAME_SIZE - 1) {
+	if (pos - buf > I2C_NAME_SIZE - 1) {
 		dev_err(dev, "%s: Invalid device name\n", "new_device");
 		return -EINVAL;
 	}
-	memcpy(info.type, buf, blank - buf);
+	memcpy(info.type, buf, pos - buf);
 
-	/* Parse remaining parameters, reject extra parameters */
-	res = sscanf(++blank, "%hi%c", &info.addr, &end);
-	if (res < 1) {
+	while (isspace(*pos))
+		pos++;
+
+	/* Parse address, saving remaining parameters. */
+	res = sscanf(pos, "%hi%c", &info.addr, &end);
+	if (res < 1 || !isspace(end)) {
 		dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 		return -EINVAL;
 	}
-	if (res > 1  && end != '\n') {
-		dev_err(dev, "%s: Extra parameters\n", "new_device");
-		return -EINVAL;
+	if (res > 1 && end != '\n') {
+		if (isspace(end)) {
+			/* Extra parms, skip the address and space. */
+			while (!isspace(*pos))
+				pos++;
+			while (isspace(*pos))
+				pos++;
+			info.parms = pos;
+		} else {
+			dev_err(dev, "%s: Extra parameters\n", "new_device");
+			return -EINVAL;
+		}
 	}
 
 	if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 200cf13b..35db0dd 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -225,6 +225,7 @@ struct i2c_client {
 	char name[I2C_NAME_SIZE];
 	struct i2c_adapter *adapter;	/* the adapter we sit on	*/
 	struct device dev;		/* the device structure		*/
+	char *parms;			/* sysfs extra parms		*/
 	int irq;			/* irq issued by device		*/
 	struct list_head detected;
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
@@ -282,6 +283,7 @@ static inline int i2c_slave_event(struct i2c_client *client,
  * @archdata: copied into i2c_client.dev.archdata
  * @of_node: pointer to OpenFirmware device node
  * @fwnode: device node supplied by the platform firmware
+ * @parms: Parameters supplied on the sysfs command line
  * @irq: stored in i2c_client.irq
  *
  * I2C doesn't actually support hardware probing, although controllers and
@@ -303,6 +305,7 @@ struct i2c_board_info {
 	struct dev_archdata	*archdata;
 	struct device_node *of_node;
 	struct fwnode_handle *fwnode;
+	char            *parms;
 	int		irq;
 };
 
-- 
2.5.0

[PATCH 2/3] ipmi: Handle I2C parms in the SSIF driver.

[minyard]

From: Corey Minyard <cminyard@mvista.com>

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 drivers/char/ipmi/ipmi_ssif.c | 62 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 8b3be8b..740fdea 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -200,7 +200,7 @@ struct ssif_info {
 	struct ipmi_smi_msg *waiting_msg;
 	struct ipmi_smi_msg *curr_msg;
 	enum ssif_intf_state ssif_state;
-	unsigned long       ssif_debug;
+	unsigned int        ssif_debug;
 
 	struct ipmi_smi_handlers handlers;
 
@@ -1386,6 +1386,60 @@ restart:
 	return found;
 }
 
+static int ssif_parse_parms(struct ssif_info *ssif_info,
+			    const char *parms, u8 *slave_addr)
+{
+	int rv;
+	char end;
+
+	if (!parms)
+		return 0;
+
+	while (*parms) {
+		const char *next = parms;
+		const char *val;
+		int parmlen;
+
+		while (*next && !isspace(*next) && *next != '=')
+			next++;
+
+		if (*next != '=') {
+			pr_err("IPMI SSIF invalid parm starting at %s\n",
+			       parms);
+			return -EINVAL;
+		}
+
+		parmlen = next - parms;
+		next++;
+		val = next;
+		while (*next && !isspace(*next))
+			next++;
+
+		if (strncmp(parms, "ipmb", parmlen) == 0) {
+			rv = sscanf(val, "%hhx%c", slave_addr, &end);
+			if ((rv < 1) || ((rv > 1) && !isspace(end))) {
+				pr_err("Invalid ipmb address: %s\n", val);
+				return -EINVAL;
+			}
+		} else if (strncmp(parms, "debug", parmlen) == 0) {
+			rv = sscanf(val, "%i%c", &ssif_info->ssif_debug, &end);
+			if ((rv < 1) || ((rv > 1) && !isspace(end))) {
+				pr_err("Invalid debug value: %s\n", val);
+				return -EINVAL;
+			}
+		} else {
+			pr_err("Invalid IPMI SSIF parameter: %s\n", parms);
+			return -EINVAL;
+		}
+
+		while (*next && isspace(*next))
+			next++;
+		parms = next;
+	}
+
+	return 0;
+}
+
 static bool check_acpi(struct ssif_info *ssif_info, struct device *dev)
 {
 #ifdef CONFIG_ACPI
@@ -1435,6 +1489,12 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		if (!addr_info) {
 			/* Must have come in through sysfs. */
 			ssif_info->addr_source = SI_HOTMOD;
+			rv = ssif_parse_parms(ssif_info, client->parms,
+					      &slave_addr);
+			if (rv) {
+				pr_err(PFX "Unable to parse parms from i2c\n");
+				goto out;
+			}
 		} else {
 			ssif_info->addr_source = addr_info->addr_src;
 			ssif_info->ssif_debug = addr_info->debug;
-- 
2.5.0

[PATCH 3/3] i2c-smbus: Allow parms to be passed in from sysfs new_device

[minyard]

From: Corey Minyard <cminyard@mvista.com>

This allows "irq=<num>" and "edge" to be passed in to the i2c new_device
after the name and i2c address.  This way the alert can be configured
without having to have platform data.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---
 drivers/i2c/i2c-smbus.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index cecd423..a3b7781 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -23,6 +23,7 @@
 #include <linux/i2c.h>
 #include <linux/i2c-smbus.h>
 #include <linux/slab.h>
+#include <linux/ctype.h>
 
 struct i2c_smbus_alert {
 	unsigned int		alert_edge_triggered:1;
@@ -123,15 +124,86 @@ static irqreturn_t smbalert_irq(int irq, void *d)
 	return IRQ_HANDLED;
 }
 
+static struct i2c_smbus_alert_setup *smbalert_parse_parms(struct device *dev,
+		const char *parms,
+		struct i2c_smbus_alert_setup *data)
+{
+	int rv;
+	char end;
+
+	if (!parms)
+		return NULL;
+
+	data->alert_edge_triggered = false;
+	while (*parms) {
+		const char *next = parms;
+		const char *val;
+		int parmlen;
+
+		while (*next && !isspace(*next) && *next != '=')
+			next++;
+
+		parmlen = next - parms;
+
+		if (*next == '=') {
+			next++;
+			val = next;
+			while (*next && !isspace(*next))
+				next++;
+		} else {
+			val = NULL;
+		}
+
+		if (strncmp(parms, "irq", parmlen) == 0) {
+			if (!val) {
+				dev_err(dev, "no irq parm value given\n");
+				return NULL;
+			}
+			rv = sscanf(val, "%d%c", &data->irq, &end);
+			if ((rv < 1) || ((rv > 1) && !isspace(end))) {
+				dev_err(dev, "Invalid irq parm: %s\n", val);
+				return NULL;
+			}
+		} else if (strncmp(parms, "edge", parmlen) == 0) {
+			if (val) {
+				dev_err(dev, "Value given with edge parm: %s\n",
+					val);
+				return NULL;
+			}
+			data->alert_edge_triggered = true;
+		} else {
+			dev_err(dev, "Invalid parameter: %s\n", parms);
+			return NULL;
+		}
+
+		while (*next && isspace(*next))
+			next++;
+		parms = next;
+	}
+
+	return data;
+}
+
 /* Setup SMBALERT# infrastructure */
 static int smbalert_probe(struct i2c_client *ara,
 			  const struct i2c_device_id *id)
 {
 	struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev);
+	struct i2c_smbus_alert_setup dummy_setup;
 	struct i2c_smbus_alert *alert;
 	struct i2c_adapter *adapter = ara->adapter;
 	int res;
 
+	if (ara->parms)
+		/* Came in through sysfs. */
+		setup = smbalert_parse_parms(&ara->dev, ara->parms,
+					     &dummy_setup);
+
+	if (!setup) {
+		dev_err(&ara->dev, "SMBus alert without setup\n");
+		return -ENODEV;
+	}
+
 	alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
 			     GFP_KERNEL);
 	if (!alert)
-- 
2.5.0