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[72.90.70.109]) by smtp.gmail.com with ESMTPSA id o70-20020a374149000000b006e702033b15sm7721430qka.66.2022.12.19.16.05.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Dec 2022 16:05:45 -0800 (PST) From: "Cormier, Jonathan" To: linux-hwmon@vger.kernel.org Cc: John Pruitt , Jean Delvare , Guenter Roeck , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Rob Herring , Krzysztof Kozlowski , Bob Duke , "Cormier, Jonathan" Subject: [PATCH v2 3/4] hwmon: ltc2945: Allow setting shunt resistor Date: Mon, 19 Dec 2022 19:04:56 -0500 Message-Id: <20221220000457.1163446-4-jcormier@criticallink.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221220000457.1163446-1-jcormier@criticallink.com> References: <20221214220727.1350784-1-jcormier@criticallink.com> <20221220000457.1163446-1-jcormier@criticallink.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1752229002631218550?= X-GMAIL-MSGID: =?utf-8?q?1752689387596693857?= From: John Pruitt Added the ability to specify the value of the shunt resistor in the device tree instead of assuming it is 1 milliOhm. The value in the device tree has the name shunt-resistor-micro-ohms and the default value is 1000 micro-ohms in order to preserve the current behavior. Signed-off-by: "Cormier, Jonathan" Signed-off-by: John Pruitt --- drivers/hwmon/ltc2945.c | 80 +++++++++++++++++++++++++---------------- 1 file changed, 50 insertions(+), 30 deletions(-) -- 2.25.1 diff --git a/drivers/hwmon/ltc2945.c b/drivers/hwmon/ltc2945.c index 9af3e3821152..fc7d399b2c85 100644 --- a/drivers/hwmon/ltc2945.c +++ b/drivers/hwmon/ltc2945.c @@ -64,6 +64,16 @@ static const struct of_device_id __maybe_unused ltc2945_of_match[] = { }; MODULE_DEVICE_TABLE(of, ltc2945_of_match); +/** + * struct ltc2945_data - LTC2945 device data + * @regmap: regmap device + * @shunt_resistor: shunt resistor value in micro ohms (1000 by default) + */ +struct ltc2945_data { + struct regmap *regmap; + u32 shunt_resistor; +}; + static inline bool is_power_reg(u8 reg) { return reg < LTC2945_SENSE_H; @@ -72,7 +82,9 @@ static inline bool is_power_reg(u8 reg) /* Return the value from the given register in uW, mV, or mA */ static long long ltc2945_reg_to_val(struct device *dev, u8 reg) { - struct regmap *regmap = dev_get_drvdata(dev); + struct ltc2945_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; + u32 shunt_resistor = data->shunt_resistor; unsigned int control; u8 buf[3]; long long val; @@ -98,9 +110,7 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg) case LTC2945_MAX_POWER_THRES_H: case LTC2945_MIN_POWER_THRES_H: /* - * Convert to uW by assuming current is measured with - * an 1mOhm sense resistor, similar to current - * measurements. + * Convert to uW * Control register bit 0 selects if voltage at SENSE+/VDD * or voltage at ADIN is used to measure power. */ @@ -114,6 +124,8 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg) /* 0.5 mV * 25 uV = 0.0125 uV resolution. */ val = (val * 25LL) >> 1; } + val *= 1000; + val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor); break; case LTC2945_VIN_H: case LTC2945_MAX_VIN_H: @@ -136,14 +148,9 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg) case LTC2945_MIN_SENSE_H: case LTC2945_MAX_SENSE_THRES_H: case LTC2945_MIN_SENSE_THRES_H: - /* - * 25 uV resolution. Convert to current as measured with - * an 1 mOhm sense resistor, in mA. If a different sense - * resistor is installed, calculate the actual current by - * dividing the reported current by the sense resistor value - * in mOhm. - */ - val *= 25; + /* 25 uV resolution. Convert to mA. */ + val *= 25 * 1000; + val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor); break; default: return -EINVAL; @@ -154,7 +161,9 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg) static int ltc2945_val_to_reg(struct device *dev, u8 reg, unsigned long val) { - struct regmap *regmap = dev_get_drvdata(dev); + struct ltc2945_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; + u32 shunt_resistor = data->shunt_resistor; unsigned int control; int ret; @@ -165,9 +174,6 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg, case LTC2945_MAX_POWER_THRES_H: case LTC2945_MIN_POWER_THRES_H: /* - * Convert to register value by assuming current is measured - * with an 1mOhm sense resistor, similar to current - * measurements. * Control register bit 0 selects if voltage at SENSE+/VDD * or voltage at ADIN is used to measure power, which in turn * determines register calculations. @@ -177,14 +183,16 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg, return ret; if (control & CONTROL_MULT_SELECT) { /* 25 mV * 25 uV = 0.625 uV resolution. */ - val = DIV_ROUND_CLOSEST(val, 625); + val *= shunt_resistor; + val = DIV_ROUND_CLOSEST(val, 625 * 1000); } else { /* * 0.5 mV * 25 uV = 0.0125 uV resolution. * Divide first to avoid overflow; * accept loss of accuracy. */ - val = DIV_ROUND_CLOSEST(val, 25) * 2; + val *= shunt_resistor; + val = DIV_ROUND_CLOSEST(val, 25 * 1000) * 2; } break; case LTC2945_VIN_H: @@ -208,14 +216,9 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg, case LTC2945_MIN_SENSE_H: case LTC2945_MAX_SENSE_THRES_H: case LTC2945_MIN_SENSE_THRES_H: - /* - * 25 uV resolution. Convert to current as measured with - * an 1 mOhm sense resistor, in mA. If a different sense - * resistor is installed, calculate the actual current by - * dividing the reported current by the sense resistor value - * in mOhm. - */ - val = DIV_ROUND_CLOSEST(val, 25); + /* 25 uV resolution. Convert to mA. */ + val *= shunt_resistor; + val = DIV_ROUND_CLOSEST(val, 25 * 1000); break; default: return -EINVAL; @@ -240,7 +243,8 @@ static ssize_t ltc2945_value_store(struct device *dev, const char *buf, size_t count) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); - struct regmap *regmap = dev_get_drvdata(dev); + struct ltc2945_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; u8 reg = attr->index; unsigned long val; u8 regbuf[3]; @@ -275,7 +279,8 @@ static ssize_t ltc2945_history_store(struct device *dev, const char *buf, size_t count) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); - struct regmap *regmap = dev_get_drvdata(dev); + struct ltc2945_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; u8 reg = attr->index; int num_regs = is_power_reg(reg) ? 3 : 2; u8 buf_min[3] = { 0xff, 0xff, 0xff }; @@ -327,7 +332,8 @@ static ssize_t ltc2945_bool_show(struct device *dev, struct device_attribute *da, char *buf) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); - struct regmap *regmap = dev_get_drvdata(dev); + struct ltc2945_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; unsigned int fault; int ret; @@ -456,6 +462,12 @@ static int ltc2945_probe(struct i2c_client *client) struct device *dev = &client->dev; struct device *hwmon_dev; struct regmap *regmap; + struct ltc2945_data *data; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + dev_set_drvdata(dev, data); regmap = devm_regmap_init_i2c(client, <c2945_regmap_config); if (IS_ERR(regmap)) { @@ -463,11 +475,19 @@ static int ltc2945_probe(struct i2c_client *client) return PTR_ERR(regmap); } + data->regmap = regmap; + if (device_property_read_u32(dev, "shunt-resistor-micro-ohms", + &data->shunt_resistor)) + data->shunt_resistor = 1000; + + if (data->shunt_resistor == 0) + return -EINVAL; + /* Clear faults */ regmap_write(regmap, LTC2945_FAULT, 0x00); hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, - regmap, + data, ltc2945_groups); return PTR_ERR_OR_ZERO(hwmon_dev); }