Re: [PATCH v5 1/5] hwmon: (max31790) Rework to use regmap

From: Guenter Roeck
Date: Thu May 20 2021 - 01:12:12 EST

On 5/11/21 6:30 PM, Václav Kubernát wrote:
Converting the driver to use regmap makes it more generic. It also makes
it a lot easier to debug through debugfs.

Signed-off-by: Václav Kubernát <kubernat@xxxxxxxxx>
---
drivers/hwmon/Kconfig | 1 +
drivers/hwmon/max31790.c | 254 ++++++++++++++++++++-------------------
2 files changed, 133 insertions(+), 122 deletions(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 54f04e61fb83..c2ec57672c4e 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1092,6 +1092,7 @@ config SENSORS_MAX6697
config SENSORS_MAX31790
tristate "Maxim MAX31790 sensor chip"
depends on I2C
+ select REGMAP_I2C
help
If you say yes here you get support for 6-Channel PWM-Output
Fan RPM Controller.
diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
index 2c6b333a28e9..e3765ce4444a 100644
--- a/drivers/hwmon/max31790.c
+++ b/drivers/hwmon/max31790.c
@@ -12,6 +12,7 @@
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/module.h>
+#include <linux/regmap.h>
#include <linux/slab.h>
/* MAX31790 registers */
@@ -46,92 +47,53 @@
#define NR_CHANNEL 6
+#define MAX31790_REG_USER_BYTE_67 0x67
+
+#define BULK_TO_U16(msb, lsb) (((msb) << 8) + (lsb))
+#define U16_MSB(num) (((num) & 0xFF00) >> 8)
+#define U16_LSB(num) ((num) & 0x00FF)
+
+static const struct regmap_range max31790_ro_range = {
+ .range_min = MAX31790_REG_TACH_COUNT(0),
+ .range_max = MAX31790_REG_PWMOUT(0) - 1,
+};
+
+static const struct regmap_access_table max31790_wr_table = {
+ .no_ranges = &max31790_ro_range,
+ .n_no_ranges = 1,
+};
+
+static const struct regmap_range max31790_volatile_ranges[] = {
+ regmap_reg_range(MAX31790_REG_TACH_COUNT(0), MAX31790_REG_TACH_COUNT(12)),
+ regmap_reg_range(MAX31790_REG_FAN_FAULT_STATUS2, MAX31790_REG_FAN_FAULT_STATUS1),
+};
+
+static const struct regmap_access_table max31790_volatile_table = {
+ .no_ranges = max31790_volatile_ranges,
+ .n_no_ranges = 2,
+ .n_yes_ranges = 0
+};
+
+static const struct regmap_config max31790_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .reg_stride = 1,
+ .max_register = MAX31790_REG_USER_BYTE_67,
+ .wr_table = &max31790_wr_table,
+ .volatile_table = &max31790_volatile_table
+};
+
/*
* Client data (each client gets its own)
*/
struct max31790_data {
- struct i2c_client *client;
+ struct regmap *regmap;
+
struct mutex update_lock;
- bool valid; /* zero until following fields are valid */
- unsigned long last_updated; /* in jiffies */
-
- /* register values */
u8 fan_config[NR_CHANNEL];
u8 fan_dynamics[NR_CHANNEL];
- u16 fault_status;
- u16 tach[NR_CHANNEL * 2];
- u16 pwm[NR_CHANNEL];
- u16 target_count[NR_CHANNEL];
};
-static struct max31790_data *max31790_update_device(struct device *dev)
-{
- struct max31790_data *data = dev_get_drvdata(dev);
- struct i2c_client *client = data->client;
- struct max31790_data *ret = data;
- int i;
- int rv;
-
- mutex_lock(&data->update_lock);
-
- if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
- rv = i2c_smbus_read_byte_data(client,
- MAX31790_REG_FAN_FAULT_STATUS1);
- if (rv < 0)
- goto abort;
- data->fault_status = rv & 0x3F;
-
- rv = i2c_smbus_read_byte_data(client,
- MAX31790_REG_FAN_FAULT_STATUS2);
- if (rv < 0)
- goto abort;
- data->fault_status |= (rv & 0x3F) << 6;
-
- for (i = 0; i < NR_CHANNEL; i++) {
- rv = i2c_smbus_read_word_swapped(client,
- MAX31790_REG_TACH_COUNT(i));
- if (rv < 0)
- goto abort;
- data->tach[i] = rv;
-
- if (data->fan_config[i]
- & MAX31790_FAN_CFG_TACH_INPUT) {
- rv = i2c_smbus_read_word_swapped(client,
- MAX31790_REG_TACH_COUNT(NR_CHANNEL
- + i));
- if (rv < 0)
- goto abort;
- data->tach[NR_CHANNEL + i] = rv;
- } else {
- rv = i2c_smbus_read_word_swapped(client,
- MAX31790_REG_PWMOUT(i));
- if (rv < 0)
- goto abort;
- data->pwm[i] = rv;
-
- rv = i2c_smbus_read_word_swapped(client,
- MAX31790_REG_TARGET_COUNT(i));
- if (rv < 0)
- goto abort;
- data->target_count[i] = rv;
- }
- }
-
- data->last_updated = jiffies;
- data->valid = true;
- }
- goto done;
-
-abort:
- data->valid = false;
- ret = ERR_PTR(rv);
-
-done:
- mutex_unlock(&data->update_lock);
-
- return ret;
-}
-
static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
static u8 get_tach_period(u8 fan_dynamics)
@@ -159,28 +121,75 @@ static u8 bits_for_tach_period(int rpm)
return bits;
}
+static int read_reg_byte(struct regmap *regmap, u8 reg)
+{
+ int rv;
+ int val;
+
+ rv = regmap_read(regmap, reg, &val);
+ if (rv < 0)
+ return rv;
+
+ return val;
+}
+
+static int read_reg_word(struct regmap *regmap, u8 reg)
+{
+ int rv;
+ u8 val_bulk[2];
+
+ rv = regmap_bulk_read(regmap, reg, val_bulk, 2);
+ if (rv < 0)
+ return rv;
+
+ return BULK_TO_U16(val_bulk[0], val_bulk[1]);
+}
+
+static int write_reg_word(struct regmap *regmap, u8 reg, u16 val)
+{
+ u8 bulk_val[2];
+
+ bulk_val[0] = U16_MSB(val);
+ bulk_val[1] = U16_LSB(val);
+
+ return regmap_bulk_write(regmap, reg, bulk_val, 2);
+}
+
static int max31790_read_fan(struct device *dev, u32 attr, int channel,
long *val)
{
- struct max31790_data *data = max31790_update_device(dev);
- int sr, rpm;
-
- if (IS_ERR(data))
- return PTR_ERR(data);
+ struct max31790_data *data = dev_get_drvdata(dev);
+ struct regmap *regmap = data->regmap;
+ int tach, fault;
switch (attr) {
case hwmon_fan_input:
- sr = get_tach_period(data->fan_dynamics[channel]);
- rpm = RPM_FROM_REG(data->tach[channel], sr);
- *val = rpm;
+ tach = read_reg_word(regmap, MAX31790_REG_TACH_COUNT(channel));
+ if (tach < 0)
+ return tach;
+
+ *val = RPM_FROM_REG(tach, get_tach_period(data->fan_dynamics[channel]));
return 0;
case hwmon_fan_target:
- sr = get_tach_period(data->fan_dynamics[channel]);
- rpm = RPM_FROM_REG(data->target_count[channel], sr);
- *val = rpm;
+ tach = read_reg_word(regmap, MAX31790_REG_TARGET_COUNT(channel));
+ if (tach < 0)
+ return tach;
+
+ *val = RPM_FROM_REG(tach, get_tach_period(data->fan_dynamics[channel]));
return 0;
case hwmon_fan_fault:
- *val = !!(data->fault_status & (1 << channel));
+ if (channel > 6)

Please use the NR_CHANNEL constant.

+ fault = read_reg_byte(regmap, MAX31790_REG_FAN_FAULT_STATUS2);
+ else
+ fault = read_reg_byte(regmap, MAX31790_REG_FAN_FAULT_STATUS1);
+
+ if (fault < 0)
+ return fault;
+
+ if (channel > 6)
+ *val = !!(fault & (1 << (channel - 6)));
+ else
+ *val = !!(fault & (1 << channel));

Better written without conditional as
*val = !!(fault & (1 << (channel % NR_CHANNEL)));

Guenter