[PATCH v4 21/21] hwmon: (mr75203) add debugfs to read and write temperature coefficients

[Eliav Farber <farbere@amazon.com>]

This change adds debugfs to read and write temperature sensor coefficients
- g, h, j and cal5.

The coefficients can vary between product and product, so it can be very
useful to be able to modify them on the fly during the calibration
process.

e.g.:

cat /sys/kernel/debug/940f23d0000.pvt/ts_coeff_cal5
4096

echo 83000 > sys/kernel/debug/940f23d0000.pvt/ts_coeff_g

Signed-off-by: Eliav Farber <farbere@amazon.com>
---
V4 -> V3:
- Remove check of the debugfs_create_dir() return value.
- Use debugfs_create_u32() instead of debugfs_create_file().
- Return devm_add_action_or_reset() without checking return value and printing
  an error message on failure.

 drivers/hwmon/mr75203.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 8baa99a9ea83..e3670075fae4 100644
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -9,6 +9,7 @@
  */
 #include <linux/bits.h>
 #include <linux/clk.h>
+#include <linux/debugfs.h>
 #include <linux/hwmon.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
@@ -170,6 +171,7 @@ struct pvt_device {
 	struct regmap		*v_map;
 	struct clk		*clk;
 	struct reset_control	*rst;
+	struct dentry		*dbgfs_dir;
 	struct voltage_device	*vd;
 	struct voltage_channels	vm_channels;
 	struct temp_coeff	ts_coeff;
@@ -179,6 +181,30 @@ struct pvt_device {
 	u32			ip_freq;
 };
 
+static void devm_pvt_ts_dbgfs_remove(void *data)
+{
+	struct pvt_device *pvt = (struct pvt_device *)data;
+
+	debugfs_remove_recursive(pvt->dbgfs_dir);
+	pvt->dbgfs_dir = NULL;
+}
+
+static int pvt_ts_dbgfs_create(struct pvt_device *pvt, struct device *dev)
+{
+	pvt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
+
+	debugfs_create_u32("ts_coeff_h", 0644, pvt->dbgfs_dir,
+			   &pvt->ts_coeff.h);
+	debugfs_create_u32("ts_coeff_g", 0644, pvt->dbgfs_dir,
+			   &pvt->ts_coeff.g);
+	debugfs_create_u32("ts_coeff_j", 0644, pvt->dbgfs_dir,
+			   &pvt->ts_coeff.j);
+	debugfs_create_u32("ts_coeff_cal5", 0644, pvt->dbgfs_dir,
+			   &pvt->ts_coeff.cal5);
+
+	return devm_add_action_or_reset(dev, devm_pvt_ts_dbgfs_remove, pvt);
+}
+
 static umode_t pvt_is_visible(const void *data, enum hwmon_sensor_types type,
 			      u32 attr, int channel)
 {
@@ -803,6 +829,8 @@ static int mr75203_probe(struct platform_device *pdev)
 		memset32(temp_config, HWMON_T_INPUT, ts_num);
 		pvt_temp.config = temp_config;
 		pvt_info[index++] = &pvt_temp;
+
+		pvt_ts_dbgfs_create(pvt, dev);
 	}
 
 	if (pd_num) {
-- 
2.37.1