From 3b0982ff93aab8751f2c5df456a68abed11f84da Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 31 Oct 2021 09:34:33 -0700 Subject: [PATCH] hwmon: (lm90) Improve PEC support PEC (packet error checking) support for ADM1032 is currently only enabled if the chip was auto-detected, but not if a chip is instantiated explicitly. Always enable PEC support by introducing a chip feature flag indicating partial PEC support. Also, for consistency, disable PEC support by default to match existing functionality if the chip was not auto- detected. At the same time, introduce generic support for PEC with a separate feature flag. This will be used when support for chips with full PEC functionality is added. Signed-off-by: Guenter Roeck --- Documentation/hwmon/lm90.rst | 6 ++-- drivers/hwmon/lm90.c | 56 +++++++++++++++++++----------------- 2 files changed, 32 insertions(+), 30 deletions(-) diff --git a/Documentation/hwmon/lm90.rst b/Documentation/hwmon/lm90.rst index 05391fb4042d..f107d4a159fa 100644 --- a/Documentation/hwmon/lm90.rst +++ b/Documentation/hwmon/lm90.rst @@ -423,6 +423,6 @@ two transactions will typically mean twice as much delay waiting for transaction completion, effectively doubling the register cache refresh time. I guess reliability comes at a price, but it's quite expensive this time. -So, as not everyone might enjoy the slowdown, PEC can be disabled through -sysfs. Just write 0 to the "pec" file and PEC will be disabled. Write 1 -to that file to enable PEC again. +So, as not everyone might enjoy the slowdown, PEC is disabled by default and +can be enabled through sysfs. Just write 1 to the "pec" file and PEC will be +enabled. Write 0 to that file to disable PEC again. diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c index 995b27a248e6..8ba95ea06f0c 100644 --- a/drivers/hwmon/lm90.c +++ b/drivers/hwmon/lm90.c @@ -179,6 +179,8 @@ enum chips { adm1032, adt7461, g781, lm86, lm90, lm99, #define LM90_PAUSE_FOR_CONFIG BIT(9) /* Pause conversion for config */ #define LM90_HAVE_CRIT BIT(10) /* Chip supports CRIT/OVERT register */ #define LM90_HAVE_CRIT_ALRM_SWP BIT(11) /* critical alarm bits swapped */ +#define LM90_HAVE_PEC BIT(12) /* Chip supports PEC */ +#define LM90_HAVE_PARTIAL_PEC BIT(13) /* Partial PEC support (adm1032)*/ /* LM90 status */ #define LM90_STATUS_LTHRM BIT(0) /* local THERM limit tripped */ @@ -346,7 +348,8 @@ struct lm90_params { static const struct lm90_params lm90_params[] = { [adm1032] = { .flags = LM90_HAVE_OFFSET | LM90_HAVE_REM_LIMIT_EXT - | LM90_HAVE_BROKEN_ALERT | LM90_HAVE_CRIT, + | LM90_HAVE_BROKEN_ALERT | LM90_HAVE_CRIT + | LM90_HAVE_PARTIAL_PEC, .alert_alarms = 0x7c, .max_convrate = 10, }, @@ -519,10 +522,10 @@ struct lm90_data { */ /* - * The ADM1032 supports PEC but not on write byte transactions, so we need + * If the chip supports PEC but not on write byte transactions, we need * to explicitly ask for a transaction without PEC. */ -static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value) +static inline s32 lm90_write_no_pec(struct i2c_client *client, u8 value) { return i2c_smbus_xfer(client->adapter, client->addr, client->flags & ~I2C_CLIENT_PEC, @@ -531,22 +534,24 @@ static inline s32 adm1032_write_byte(struct i2c_client *client, u8 value) /* * It is assumed that client->update_lock is held (unless we are in - * detection or initialization steps). This matters when PEC is enabled, - * because we don't want the address pointer to change between the write - * byte and the read byte transactions. + * detection or initialization steps). This matters when PEC is enabled + * for chips with partial PEC support, because we don't want the address + * pointer to change between the write byte and the read byte transactions. */ static int lm90_read_reg(struct i2c_client *client, u8 reg) { + struct lm90_data *data = i2c_get_clientdata(client); + bool partial_pec = (client->flags & I2C_CLIENT_PEC) && + (data->flags & LM90_HAVE_PARTIAL_PEC); int err; - if (client->flags & I2C_CLIENT_PEC) { - err = adm1032_write_byte(client, reg); - if (err >= 0) - err = i2c_smbus_read_byte(client); - } else - err = i2c_smbus_read_byte_data(client, reg); - - return err; + if (partial_pec) { + err = lm90_write_no_pec(client, reg); + if (err) + return err; + return i2c_smbus_read_byte(client); + } + return i2c_smbus_read_byte_data(client, reg); } /* @@ -1135,7 +1140,7 @@ static u16 temp_to_u16_adt7461(struct lm90_data *data, long val) return (val + 125) / 250 * 64; } -/* pec used for ADM1032 only */ +/* pec used for devices with PEC support */ static ssize_t pec_show(struct device *dev, struct device_attribute *dummy, char *buf) { @@ -1675,13 +1680,6 @@ static int lm90_detect(struct i2c_client *client, && (config1 & 0x3F) == 0x00 && convrate <= 0x0A) { name = "adm1032"; - /* - * The ADM1032 supports PEC, but only if combined - * transactions are not used. - */ - if (i2c_check_functionality(adapter, - I2C_FUNC_SMBUS_BYTE)) - info->flags |= I2C_CLIENT_PEC; } else if (chip_id == 0x51 /* ADT7461 */ && (config1 & 0x1B) == 0x00 @@ -2005,10 +2003,6 @@ static int lm90_probe(struct i2c_client *client) data->kind = (enum chips)of_device_get_match_data(&client->dev); else data->kind = i2c_match_id(lm90_id, client)->driver_data; - if (data->kind == adm1032) { - if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) - client->flags &= ~I2C_CLIENT_PEC; - } /* * Different devices have different alarm bits triggering the @@ -2019,6 +2013,14 @@ static int lm90_probe(struct i2c_client *client) /* Set chip capabilities */ data->flags = lm90_params[data->kind].flags; + if ((data->flags & (LM90_HAVE_PEC | LM90_HAVE_PARTIAL_PEC)) && + !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_PEC)) + data->flags &= ~(LM90_HAVE_PEC | LM90_HAVE_PARTIAL_PEC); + + if ((data->flags & LM90_HAVE_PARTIAL_PEC) && + !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) + data->flags &= ~LM90_HAVE_PARTIAL_PEC; + data->chip.ops = &lm90_ops; data->chip.info = data->info; @@ -2081,7 +2083,7 @@ static int lm90_probe(struct i2c_client *client) * The 'pec' attribute is attached to the i2c device and thus created * separately. */ - if (client->flags & I2C_CLIENT_PEC) { + if (data->flags & (LM90_HAVE_PEC | LM90_HAVE_PARTIAL_PEC)) { err = device_create_file(dev, &dev_attr_pec); if (err) return err;