[PATCH v3 18/19] 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>
---
 drivers/hwmon/mr75203.c | 196 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 196 insertions(+)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index d9fc5d225868..8c30f0521452 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>
@@ -153,6 +154,7 @@ 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;
@@ -162,6 +164,198 @@ struct pvt_device {
 	u32			ip_freq;
 };
 
+static ssize_t pvt_ts_coeff_h_read(struct file *file,
+				   char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	char buf[16];
+	unsigned int len;
+
+	len = sprintf(buf, "%u\n", pvt->ts_coeff.h);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t pvt_ts_coeff_h_write(struct file *file,
+				    const char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	int ret;
+	u32 coeff;
+
+	ret = kstrtou32_from_user(user_buf, count, 0, &coeff);
+	if (ret)
+		return ret;
+
+	pvt->ts_coeff.h = coeff;
+
+	return count;
+}
+
+static const struct file_operations pvt_ts_coeff_h_fops = {
+	.read = pvt_ts_coeff_h_read,
+	.write = pvt_ts_coeff_h_write,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+static ssize_t pvt_ts_coeff_g_read(struct file *file,
+				   char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	char buf[16];
+	unsigned int len;
+
+	len = sprintf(buf, "%u\n", pvt->ts_coeff.g);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t pvt_ts_coeff_g_write(struct file *file,
+				    const char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	int ret;
+	u32 coeff;
+
+	ret = kstrtou32_from_user(user_buf, count, 0, &coeff);
+	if (ret)
+		return ret;
+
+	pvt->ts_coeff.g = coeff;
+
+	return count;
+}
+
+static const struct file_operations pvt_ts_coeff_g_fops = {
+	.read = pvt_ts_coeff_g_read,
+	.write = pvt_ts_coeff_g_write,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+static ssize_t pvt_ts_coeff_j_read(struct file *file,
+				   char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	char buf[16];
+	unsigned int len;
+
+	len = sprintf(buf, "%d\n", pvt->ts_coeff.j);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t pvt_ts_coeff_j_write(struct file *file,
+				    const char __user *user_buf,
+				    size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	int ret;
+	s32 coeff;
+
+	ret = kstrtos32_from_user(user_buf, count, 0, &coeff);
+	if (ret)
+		return ret;
+
+	pvt->ts_coeff.j = coeff;
+
+	return count;
+}
+
+static const struct file_operations pvt_ts_coeff_j_fops = {
+	.read = pvt_ts_coeff_j_read,
+	.write = pvt_ts_coeff_j_write,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+static ssize_t pvt_ts_coeff_cal5_read(struct file *file,
+				      char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	char buf[16];
+	unsigned int len;
+
+	len = sprintf(buf, "%u\n", pvt->ts_coeff.cal5);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t pvt_ts_coeff_cal5_write(struct file *file,
+				       const char __user *user_buf,
+				       size_t count, loff_t *ppos)
+{
+	struct pvt_device *pvt = file->private_data;
+	int ret;
+	u32 coeff;
+
+	ret = kstrtou32_from_user(user_buf, count, 0, &coeff);
+	if (ret)
+		return ret;
+
+	if (coeff == 0)
+		return -EINVAL;
+
+	pvt->ts_coeff.cal5 = coeff;
+
+	return count;
+}
+
+static const struct file_operations pvt_ts_coeff_cal5_fops = {
+	.read = pvt_ts_coeff_cal5_read,
+	.write = pvt_ts_coeff_cal5_write,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+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)
+{
+	int ret;
+
+	pvt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
+	if (!pvt->dbgfs_dir) {
+		dev_err(dev, "Failed to create dbgfs_dir\n");
+		return -EINVAL;
+	}
+
+	debugfs_create_file("ts_coeff_h", 0644, pvt->dbgfs_dir, pvt,
+			    &pvt_ts_coeff_h_fops);
+	debugfs_create_file("ts_coeff_g", 0644, pvt->dbgfs_dir, pvt,
+			    &pvt_ts_coeff_g_fops);
+	debugfs_create_file("ts_coeff_j", 0644, pvt->dbgfs_dir, pvt,
+			    &pvt_ts_coeff_j_fops);
+	debugfs_create_file("ts_coeff_cal5", 0644, pvt->dbgfs_dir,  pvt,
+			    &pvt_ts_coeff_cal5_fops);
+
+	ret = devm_add_action_or_reset(dev, devm_pvt_ts_dbgfs_remove, pvt);
+	if (ret) {
+		dev_err(dev, "failed to add action to remove pvt dbgfs (%d)\n",
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
 static umode_t pvt_is_visible(const void *data, enum hwmon_sensor_types type,
 			      u32 attr, int channel)
 {
@@ -814,6 +1008,8 @@ 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