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hwmon: (mr75203) add VM pre-scaler x2 support

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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 <farbere@amazon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220908152449.35457-15-farbere@amazon.com
[groeck: Addressed conflicts against commit d59eacaac953]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Eliav Farber 2022-09-08 15:24:42 +00:00 committed by Guenter Roeck
parent 64a2486c39
commit 430c0d7ff5
1 changed files with 53 additions and 2 deletions
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55
drivers/hwmon/mr75203.c
View File

@ -17,6 +17,7 @@
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/units.h>
/* 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)