From 430c0d7ff56b7e324eb36c490d513c0ef9c99860 Mon Sep 17 00:00:00 2001 From: Eliav Farber Date: Thu, 8 Sep 2022 15:24:42 +0000 Subject: [PATCH] hwmon: (mr75203) add VM pre-scaler x2 support Add support for mr76006 pre-scaler which provides divide-by-2 scaling of the input voltage, so that it can be presented to the VM for measurement within its range (the VM input range is limited from -0.1V to 1V). The driver reads from the device-tree all the channels that use the mr76006 pre-scaler and multiplies the voltage result by a factor of 2, to represent to the user with the actual voltage input source. Channels that are not in the device-tree are multiplied by a factor of 1. Signed-off-by: Eliav Farber Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20220908152449.35457-15-farbere@amazon.com [groeck: Addressed conflicts against commit d59eacaac953] Signed-off-by: Guenter Roeck --- drivers/hwmon/mr75203.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 53 insertions(+), 2 deletions(-) diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c index 0eb1712..c603132 100644 --- a/drivers/hwmon/mr75203.c +++ b/drivers/hwmon/mr75203.c @@ -17,6 +17,7 @@ #include #include #include +#include #include /* PVT Common register */ @@ -108,17 +109,24 @@ #define PVT_N_CONST 90 #define PVT_R_CONST 245805 +#define PRE_SCALER_X1 1 +#define PRE_SCALER_X2 2 + /** * struct voltage_device - VM single input parameters. * @vm_map: Map channel number to VM index. * @ch_map: Map channel number to channel index. + * @pre_scaler: Pre scaler value (1 or 2) used to normalize the voltage output + * result. * * The structure provides mapping between channel-number (0..N-1) to VM-index * (0..num_vm-1) and channel-index (0..ch_num-1) where N = num_vm * ch_num. + * It also provides normalization factor for the VM equation. */ struct voltage_device { u32 vm_map; u32 ch_map; + u32 pre_scaler; }; /** @@ -207,8 +215,8 @@ static int pvt_read_in(struct device *dev, u32 attr, int channel, long *val) { struct pvt_device *pvt = dev_get_drvdata(dev); struct regmap *v_map = pvt->v_map; + u32 n, stat, pre_scaler; u8 vm_idx, ch_idx; - u32 n, stat; int ret; if (channel >= pvt->vm_channels.total) @@ -231,6 +239,7 @@ static int pvt_read_in(struct device *dev, u32 attr, int channel, long *val) return ret; n &= SAMPLE_DATA_MSK; + pre_scaler = pvt->vd[channel].pre_scaler; /* * Convert the N bitstream count into voltage. * To support negative voltage calculation for 64bit machines @@ -242,7 +251,8 @@ static int pvt_read_in(struct device *dev, u32 attr, int channel, long *val) * BIT(x) may not be used instead of (1 << x) because it's * unsigned. */ - *val = (PVT_N_CONST * (long)n - PVT_R_CONST) / (1 << PVT_CONV_BITS); + *val = pre_scaler * (PVT_N_CONST * (long)n - PVT_R_CONST) / + (1 << PVT_CONV_BITS); return 0; default: @@ -594,6 +604,43 @@ static int pvt_get_active_channel(struct device *dev, struct pvt_device *pvt, return 0; } +static int pvt_get_pre_scaler(struct device *dev, struct pvt_device *pvt) +{ + u8 *pre_scaler_ch_list; + int i, ret, num_ch; + u32 channel; + + /* Set default pre-scaler value to be 1. */ + for (i = 0; i < pvt->vm_channels.total; i++) + pvt->vd[i].pre_scaler = PRE_SCALER_X1; + + /* Get number of channels configured in "moortec,vm-pre-scaler-x2". */ + num_ch = device_property_count_u8(dev, "moortec,vm-pre-scaler-x2"); + if (num_ch <= 0) + return 0; + + pre_scaler_ch_list = kcalloc(num_ch, sizeof(*pre_scaler_ch_list), + GFP_KERNEL); + if (!pre_scaler_ch_list) + return -ENOMEM; + + /* Get list of all channels that have pre-scaler of 2. */ + ret = device_property_read_u8_array(dev, "moortec,vm-pre-scaler-x2", + pre_scaler_ch_list, num_ch); + if (ret) + goto out; + + for (i = 0; i < num_ch; i++) { + channel = pre_scaler_ch_list[i]; + pvt->vd[channel].pre_scaler = PRE_SCALER_X2; + } + +out: + kfree(pre_scaler_ch_list); + + return ret; +} + static int mr75203_probe(struct platform_device *pdev) { u32 ts_num, vm_num, pd_num, ch_num, val, index, i; @@ -709,6 +756,10 @@ static int mr75203_probe(struct platform_device *pdev) if (ret) return ret; + ret = pvt_get_pre_scaler(dev, pvt); + if (ret) + return ret; + in_config = devm_kcalloc(dev, pvt->vm_channels.total + 1, sizeof(*in_config), GFP_KERNEL); if (!in_config) -- 2.7.4