[v5,1/1] hwmon: (it87) Add DMI table for future extensions

Commit Message

Frank Crawford Nov. 5, 2022, 11:25 p.m. UTC

Add in DMI matching table to match various board quirks and settings.
This will be useful for future extentions, but will start with the
existing definition of the Shuttle SN68PT.

Signed-off-by: Frank Crawford <[e-mail]>
---

Changes in this patch set:

* Define the DMI matching table for board specific settings during the
  chip initialisation and move the only current board specific setting
  to this new table.

* Export the table for use by udev.

v2: updates following comments:

* Converted to use callback function.

* Moved call to callback funtion to sio_data into it87_find in line
  with other settings for sio_data.  This requires dmi_data also passed
  to access additional data.

* Added macro for defining entries in DMI table to simplify future 
  additions.

* Note dmi_data is defined in sm_it87_init to simplify tests and for
  future additions.

v3: further updates following comments:

* Proper use of callback functions for DMI functions.  This also
  involves saving dmi_data in a static variable for use as required.

* Moved to dmi_check_system() for testing DMI table.

v4: further cleanups following comments

* Note the macro IT87_DMI_MATCH_VND includes callback argument for use
  by a future update.

v5: corrected patch submission format.

 drivers/hwmon/it87.c | 72 ++++++++++++++++++++++++++++++++------------
 1 file changed, 53 insertions(+), 19 deletions(-)

Comments

Guenter Roeck Nov. 11, 2022, 4:21 p.m. UTC | #1

On Sun, Nov 06, 2022 at 10:25:32AM +1100, Frank Crawford wrote:
> Add in DMI matching table to match various board quirks and settings.
> This will be useful for future extentions, but will start with the
> existing definition of the Shuttle SN68PT.
> 
> Signed-off-by: Frank Crawford <[e-mail]>

Applied to hwmon-next.

Thanks,
Guenter

Patch

diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 73ed21ab325b..9997f76b1f4a 100644
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -567,6 +567,14 @@  struct it87_data {
 	s8 auto_temp[NUM_AUTO_PWM][5];	/* [nr][0] is point1_temp_hyst */
 };
 
+/* Board specific settings from DMI matching */
+struct it87_dmi_data {
+	u8 skip_pwm;		/* pwm channels to skip for this board  */
+};
+
+/* Global for results from DMI matching, if needed */
+static struct it87_dmi_data *dmi_data;
+
 static int adc_lsb(const struct it87_data *data, int nr)
 {
 	int lsb;
@@ -2393,7 +2401,6 @@  static int __init it87_find(int sioaddr, unsigned short *address,
 {
 	int err;
 	u16 chip_type;
-	const char *board_vendor, *board_name;
 	const struct it87_devices *config;
 
 	err = superio_enter(sioaddr);
@@ -2812,24 +2819,9 @@  static int __init it87_find(int sioaddr, unsigned short *address,
 	if (sio_data->beep_pin)
 		pr_info("Beeping is supported\n");
 
-	/* Disable specific features based on DMI strings */
-	board_vendor = dmi_get_system_info(DMI_BOARD_VENDOR);
-	board_name = dmi_get_system_info(DMI_BOARD_NAME);
-	if (board_vendor && board_name) {
-		if (strcmp(board_vendor, "nVIDIA") == 0 &&
-		    strcmp(board_name, "FN68PT") == 0) {
-			/*
-			 * On the Shuttle SN68PT, FAN_CTL2 is apparently not
-			 * connected to a fan, but to something else. One user
-			 * has reported instant system power-off when changing
-			 * the PWM2 duty cycle, so we disable it.
-			 * I use the board name string as the trigger in case
-			 * the same board is ever used in other systems.
-			 */
-			pr_info("Disabling pwm2 due to hardware constraints\n");
-			sio_data->skip_pwm = BIT(1);
-		}
-	}
+	/* Set values based on DMI matches */
+	if (dmi_data)
+		sio_data->skip_pwm |= dmi_data->skip_pwm;
 
 exit:
 	superio_exit(sioaddr);
@@ -3307,6 +3299,46 @@  static int __init it87_device_add(int index, unsigned short address,
 	return err;
 }
 
+/* callback function for DMI */
+static int it87_dmi_cb(const struct dmi_system_id *dmi_entry)
+{
+	dmi_data = dmi_entry->driver_data;
+
+	if (dmi_data && dmi_data->skip_pwm)
+		pr_info("Disabling pwm2 due to hardware constraints\n");
+
+	return 1;
+}
+
+/*
+ * On the Shuttle SN68PT, FAN_CTL2 is apparently not
+ * connected to a fan, but to something else. One user
+ * has reported instant system power-off when changing
+ * the PWM2 duty cycle, so we disable it.
+ * I use the board name string as the trigger in case
+ * the same board is ever used in other systems.
+ */
+static struct it87_dmi_data nvidia_fn68pt = {
+	.skip_pwm = BIT(1),
+};
+
+#define IT87_DMI_MATCH_VND(vendor, name, cb, data) \
+	{ \
+		.callback = cb, \
+		.matches = { \
+			DMI_EXACT_MATCH(DMI_BOARD_VENDOR, vendor), \
+			DMI_EXACT_MATCH(DMI_BOARD_NAME, name), \
+		}, \
+		.driver_data = data, \
+	}
+
+static const struct dmi_system_id it87_dmi_table[] __initconst = {
+	IT87_DMI_MATCH_VND("nVIDIA", "FN68PT", it87_dmi_cb, &nvidia_fn68pt),
+	{ }
+
+};
+MODULE_DEVICE_TABLE(dmi, it87_dmi_table);
+
 static int __init sm_it87_init(void)
 {
 	int sioaddr[2] = { REG_2E, REG_4E };
@@ -3319,6 +3351,8 @@  static int __init sm_it87_init(void)
 	if (err)
 		return err;
 
+	dmi_check_system(it87_dmi_table);
+
 	for (i = 0; i < ARRAY_SIZE(sioaddr); i++) {
 		memset(&sio_data, 0, sizeof(struct it87_sio_data));
 		isa_address[i] = 0;