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Message-ID: <6aabb517-c46e-bcf8-c93d-b6fa1fe8eb3a@roeck-us.net>
Date: Thu, 17 Mar 2022 06:28:53 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Chris Packham <chris.packham@...iedtelesis.co.nz>,
jdelvare@...e.com, robh+dt@...nel.org
Cc: linux-hwmon@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] hwmon: (adt7475) Add support for pin configuration
On 3/16/22 16:41, Chris Packham wrote:
> The adt7473, adt7475, adt7476 and adt7490 have pins that can be used for
> different functions. On the adt7473 and adt7475 this is pins 5 and 9.
> On the adt7476 and adt7490 this is pins 10 and 14.
>
> The first pin can either be PWM2(default) or SMBALERT#. The second pin
> can be TACH4(default), THERM#, SMBALERT# or GPIO.
>
> The adt7475 driver has always been able to detect the configuration if
> it had been done by an earlier boot stage. Add support for configuring
> the pins based on the hardware description in the device tree.
>
> Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
> ---
> drivers/hwmon/adt7475.c | 95 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 95 insertions(+)
>
> diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
> index 9d5b019651f2..ad5e5a7a844b 100644
> --- a/drivers/hwmon/adt7475.c
> +++ b/drivers/hwmon/adt7475.c
> @@ -112,6 +112,8 @@
> #define CONFIG3_THERM 0x02
>
> #define CONFIG4_PINFUNC 0x03
> +#define CONFIG4_THERM 0x01
> +#define CONFIG4_SMBALERT 0x02
> #define CONFIG4_MAXDUTY 0x08
> #define CONFIG4_ATTN_IN10 0x30
> #define CONFIG4_ATTN_IN43 0xC0
> @@ -1460,6 +1462,95 @@ static int adt7475_update_limits(struct i2c_client *client)
> return 0;
> }
>
> +static int load_pin10_config(const struct i2c_client *client, const char *propname)
> +{
A better function name would probably be load_config3() or similar.
> + const char *function;
> + u8 config3;
> + int err;
> +
> + err = of_property_read_string(client->dev.of_node, propname, &function);
> + if (!err) {
> + config3 = adt7475_read(REG_CONFIG3);
error check missing (I see the driver is notorious for that, but that is not
a reason to keep doing it).
> +
> + if (!strcmp("pwm2", function))
> + config3 &= ~CONFIG3_SMBALERT;
> + else if (!strcmp("smbalert#", function))
> + config3 |= CONFIG3_SMBALERT;
> + else
> + return -EINVAL;
> +
> + return i2c_smbus_write_byte_data(client, REG_CONFIG3, config3);
> + }
> +
> + return 0;
> +}
> +
> +static int load_pin14_config(const struct i2c_client *client, const char *propname)
> +{
load_config4() ?
> + const char *function;
> + u8 config4;
> + int err;
> +
> + err = of_property_read_string(client->dev.of_node, propname, &function);
> + if (!err) {
> + config4 = adt7475_read(REG_CONFIG4);
error check
> + config4 &= ~CONFIG4_PINFUNC;
> +
> + if (!strcmp("tach4", function))
> + ;
> + else if (!strcmp("therm#", function))
> + config4 |= CONFIG4_THERM;
> + else if (!strcmp("smbalert#", function))
> + config4 |= CONFIG4_SMBALERT;
> + else if (!strcmp("gpio", function))
> + config4 |= CONFIG4_PINFUNC;
> + else
> + return -EINVAL;
> +
> + return i2c_smbus_write_byte_data(client, REG_CONFIG4, config4);
> + }
> +
> + return 0;
> +}
> +
> +static int load_config(const struct i2c_client *client, int chip)
> +{
> + int err;
> + const char *conf_prop1, *conf_prop2;
conf_ prefix is unnecessary.
> +
> + switch (chip) {
> + case adt7473:
> + case adt7475:
> + conf_prop1 = "adi,pin5-function";
> + conf_prop2 = "adi,pin9-function";
> + break;
> + case adt7476:
> + case adt7490:
> + conf_prop1 = "adi,pin10-function";
> + conf_prop2 = "adi,pin14-function";
> + break;
> + default:
> + return -EINVAL;
It doesn't seem right to return -EINVAL here.
> + }
> +
> + if (chip != adt7476 && chip != adt7490)
> + return 0;
> +
Why not check this first, and what is the point of assigning values to
conf_prop1 and conf_prop2 for the other chips in the case statement above
only to return 0 here ? It would be much simpler to drop the other chips
from the case statement and have default: return 0.
> + err = load_pin10_config(client, conf_prop1);
> + if (err) {
> + dev_err(&client->dev, "failed to configure PIN10\n");
The messages are misleading. This isn't always pin 10/14.
> + return err;
> + }
> +
> + err = load_pin14_config(client, conf_prop2);
> + if (err) {
> + dev_err(&client->dev, "failed to configure PIN14\n");
> + return err;
> + }
> +
> + return 0;
> +}
> +
> static int set_property_bit(const struct i2c_client *client, char *property,
> u8 *config, u8 bit_index)
> {
> @@ -1585,6 +1676,10 @@ static int adt7475_probe(struct i2c_client *client)
> revision = adt7475_read(REG_DEVID2) & 0x07;
> }
>
> + ret = load_config(client, chip);
> + if (ret)
> + return ret;
> +
> config3 = adt7475_read(REG_CONFIG3);
> /* Pin PWM2 may alternatively be used for ALERT output */
> if (!(config3 & CONFIG3_SMBALERT))
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