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From c53aee9d78372213c34f5ebfb084b58be754a23c Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Thu, 5 May 2022 15:46:07 +0100
Subject: [PATCH] hwmon: emc2305: fixups for driver submitted to
 mailing lists

The driver had a number of issues, checkpatch warnings/errors,
and other limitations, so fix these up to make it usable.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/hwmon/emc2305.c | 73 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 71 insertions(+), 2 deletions(-)

--- a/drivers/hwmon/emc2305.c
+++ b/drivers/hwmon/emc2305.c
@@ -15,12 +15,13 @@
 static const unsigned short
 emc2305_normal_i2c[] = { 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d, I2C_CLIENT_END };
 
+#define EMC2305_REG_FAN_STATUS         0x24
+#define EMC2305_REG_FAN_STALL_STATUS   0x25
 #define EMC2305_REG_DRIVE_FAIL_STATUS  0x27
 #define EMC2305_REG_VENDOR             0xfe
 #define EMC2305_FAN_MAX                        0xff
 #define EMC2305_FAN_MIN                        0x00
 #define EMC2305_FAN_MAX_STATE          10
-#define EMC2305_DEVICE                 0x34
 #define EMC2305_VENDOR                 0x5d
 #define EMC2305_REG_PRODUCT_ID         0xfd
 #define EMC2305_TACH_REGS_UNUSE_BITS   3
@@ -39,6 +40,7 @@ emc2305_normal_i2c[] = { 0x27, 0x2c, 0x2
 #define EMC2305_RPM_FACTOR             3932160
 
 #define EMC2305_REG_FAN_DRIVE(n)       (0x30 + 0x10 * (n))
+#define EMC2305_REG_FAN_CFG(n)         (0x32 + 0x10 * (n))
 #define EMC2305_REG_FAN_MIN_DRIVE(n)   (0x38 + 0x10 * (n))
 #define EMC2305_REG_FAN_TACH(n)                (0x3e + 0x10 * (n))
 
@@ -58,6 +60,15 @@ static const struct i2c_device_id emc230
 };
 MODULE_DEVICE_TABLE(i2c, emc2305_ids);
 
+static const struct of_device_id emc2305_dt_ids[] = {
+       { .compatible = "microchip,emc2305" },
+       { .compatible = "microchip,emc2303" },
+       { .compatible = "microchip,emc2302" },
+       { .compatible = "microchip,emc2301" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, emc2305_dt_ids);
+
 /**
  * @cdev: cooling device;
  * @curr_state: cooling current state;
@@ -101,6 +112,7 @@ struct emc2305_data {
        u8 pwm_num;
        bool pwm_separate;
        u8 pwm_min[EMC2305_PWM_MAX];
+       u8 pwm_max;
        struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX];
 };
 
@@ -273,7 +285,7 @@ static int emc2305_set_pwm(struct device
        struct i2c_client *client = data->client;
        int ret;
 
-       if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX)
+       if (val < data->pwm_min[channel] || val > data->pwm_max)
                return -EINVAL;
 
        ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val);
@@ -284,6 +296,49 @@ static int emc2305_set_pwm(struct device
        return 0;
 }
 
+static int emc2305_get_tz_of(struct device *dev)
+{
+       struct device_node *np = dev->of_node;
+       struct emc2305_data *data = dev_get_drvdata(dev);
+       int ret = 0;
+       u32 val;
+       int i;
+
+       /* OF parameters are optional - overwrite default setting
+        * if some of them are provided.
+        */
+
+       ret = of_property_read_u32(np, "emc2305,cooling-levels", &val);
+       if (!ret)
+               data->max_state = (u8)val;
+       else if (ret != -EINVAL)
+               return ret;
+
+       ret = of_property_read_u32(np, "emc2305,pwm-max", &val);
+       if (!ret)
+               data->pwm_max = (u8)val;
+       else if (ret != -EINVAL)
+               return ret;
+
+       ret = of_property_read_u32(np, "emc2305,pwm-min", &val);
+       if (!ret)
+               for (i = 0; i < EMC2305_PWM_MAX; i++)
+                       data->pwm_min[i] = (u8)val;
+       else if (ret != -EINVAL)
+               return ret;
+
+       /* Not defined or 0 means one thermal zone over all cooling devices.
+        * Otherwise - separated thermal zones for each PWM channel.
+        */
+       ret = of_property_read_u32(np, "emc2305,pwm-channel", &val);
+       if (!ret)
+               data->pwm_separate = (val != 0);
+       else if (ret != -EINVAL)
+               return ret;
+
+       return 0;
+}
+
 static int emc2305_set_single_tz(struct device *dev, int idx)
 {
        struct emc2305_data *data = dev_get_drvdata(dev);
@@ -572,11 +627,18 @@ static int emc2305_probe(struct i2c_clie
                data->pwm_separate = pdata->pwm_separate;
                for (i = 0; i < EMC2305_PWM_MAX; i++)
                        data->pwm_min[i] = pdata->pwm_min[i];
+               data->pwm_max = EMC2305_FAN_MAX;
        } else {
                data->max_state = EMC2305_FAN_MAX_STATE;
                data->pwm_separate = false;
                for (i = 0; i < EMC2305_PWM_MAX; i++)
                        data->pwm_min[i] = EMC2305_FAN_MIN;
+               data->pwm_max = EMC2305_FAN_MAX;
+               if (dev->of_node) {
+                       ret = emc2305_get_tz_of(dev);
+                       if (ret < 0)
+                               return ret;
+               }
        }
 
        data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data,
@@ -597,6 +659,12 @@ static int emc2305_probe(struct i2c_clie
                        return ret;
        }
 
+       /* Acknowledge any existing faults. Stops the device responding on the
+        * SMBus alert address.
+        */
+       i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_STALL_STATUS);
+       i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_STATUS);
+
        return 0;
 }
 
@@ -612,6 +680,7 @@ static struct i2c_driver emc2305_driver
        .class  = I2C_CLASS_HWMON,
        .driver = {
                .name = "emc2305",
+               .of_match_table = emc2305_dt_ids,
        },
        .probe    = emc2305_probe,
        .remove   = emc2305_remove,