[PATCH v5 12/21] hwmon: (mr75203) add VM active channel support

From: Eliav Farber
Date: Thu Sep 08 2022 - 11:35:49 EST


Add active channel support per voltage monitor.
The number of active channels is read from the device-tree.
When absent in device-tree, all channels are assumed to be used.

This shall be useful to expose sysfs only for inputs that are connected
to a voltage source.

Setting number of active channels to 0, means that entire VM sensor is
not used.

Signed-off-by: Eliav Farber <farbere@xxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
V4 -> V3:
- Convert comments to kernel doc.
- Repalce for loop with memset.
- Add {} to outer for loop.

V3 -> V2:
- Refactor the code changes (move code to a new function and group
parameters in dedicated structure).

V2 -> V1:
- Fix compilation error for patch 08/16:
"warning: ISO C90 forbids variable length array"

drivers/hwmon/mr75203.c | 121 ++++++++++++++++++++++++++++++++--------
1 file changed, 99 insertions(+), 22 deletions(-)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 19ec9fb91202..56e19c430919 100644
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -29,6 +29,8 @@
#define CH_NUM_MSK GENMASK(31, 24)
#define CH_NUM_SFT 24

+#define VM_NUM_MAX (VM_NUM_MSK >> VM_NUM_SFT)
+
/* Macro Common Register */
#define CLK_SYNTH 0x00
#define CLK_SYNTH_LO_SFT 0
@@ -106,6 +108,31 @@
#define PVT_N_CONST 90
#define PVT_R_CONST 245805

+/**
+ * struct voltage_device - VM single input parameters.
+ * @vm_map: Map channel number to VM index.
+ * @ch_map: Map channel number to channel index.
+ *
+ * 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.
+ */
+struct voltage_device {
+ u32 vm_map;
+ u32 ch_map;
+};
+
+/**
+ * struct voltage_channels - VM channel count.
+ * @total: Total number of channels in all VMs.
+ * @max: Maximum number of channels among all VMs.
+ *
+ * The structure provides channel count information across all VMs.
+ */
+struct voltage_channels {
+ u32 total;
+ u8 max;
+};
+
struct pvt_device {
struct regmap *c_map;
struct regmap *t_map;
@@ -113,12 +140,12 @@ struct pvt_device {
struct regmap *v_map;
struct clk *clk;
struct reset_control *rst;
+ struct voltage_device *vd;
+ struct voltage_channels vm_channels;
u32 t_num;
u32 p_num;
u32 v_num;
- u32 c_num;
u32 ip_freq;
- u8 *vm_idx;
};

static umode_t pvt_is_visible(const void *data, enum hwmon_sensor_types type,
@@ -184,11 +211,11 @@ static int pvt_read_in(struct device *dev, u32 attr, int channel, long *val)
u32 n, stat;
int ret;

- if (channel >= pvt->v_num * pvt->c_num)
+ if (channel >= pvt->vm_channels.total)
return -EINVAL;

- vm_idx = pvt->vm_idx[channel / pvt->c_num];
- ch_idx = channel % pvt->c_num;
+ vm_idx = pvt->vd[channel].vm_map;
+ ch_idx = pvt->vd[channel].ch_map;

switch (attr) {
case hwmon_in_input:
@@ -398,7 +425,7 @@ static int pvt_init(struct pvt_device *pvt)
if (ret)
return ret;

- val = (BIT(pvt->c_num) - 1) | VM_CH_INIT |
+ val = (BIT(pvt->vm_channels.max) - 1) | VM_CH_INIT |
IP_POLL << SDIF_ADDR_SFT | SDIF_WRN_W | SDIF_PROG;
ret = regmap_write(v_map, SDIF_W, val);
if (ret < 0)
@@ -523,6 +550,60 @@ static int pvt_reset_control_deassert(struct device *dev, struct pvt_device *pvt
return devm_add_action_or_reset(dev, pvt_reset_control_assert, pvt);
}

+static int pvt_get_active_channel(struct device *dev, struct pvt_device *pvt,
+ u32 vm_num, u32 ch_num, u8 *vm_idx)
+{
+ u8 vm_active_ch[VM_NUM_MAX];
+ int ret, i, j, k;
+
+ ret = device_property_read_u8_array(dev, "moortec,vm-active-channels",
+ vm_active_ch, vm_num);
+ if (ret) {
+ /*
+ * Incase "moortec,vm-active-channels" property is not defined,
+ * we assume each VM sensor has all of its channels active.
+ */
+ memset(vm_active_ch, ch_num, vm_num);
+ pvt->vm_channels.max = ch_num;
+ pvt->vm_channels.total = ch_num * vm_num;
+ } else {
+ for (i = 0; i < vm_num; i++) {
+ if (vm_active_ch[i] > ch_num) {
+ dev_err(dev, "invalid active channels: %u\n",
+ vm_active_ch[i]);
+ return -EINVAL;
+ }
+
+ pvt->vm_channels.total += vm_active_ch[i];
+
+ if (vm_active_ch[i] > pvt->vm_channels.max)
+ pvt->vm_channels.max = vm_active_ch[i];
+ }
+ }
+
+ /*
+ * Map between the channel-number to VM-index and channel-index.
+ * Example - 3 VMs, "moortec,vm_active_ch" = <5 2 4>:
+ * vm_map = [0 0 0 0 0 1 1 2 2 2 2]
+ * ch_map = [0 1 2 3 4 0 1 0 1 2 3]
+ */
+ pvt->vd = devm_kcalloc(dev, pvt->vm_channels.total, sizeof(*pvt->vd),
+ GFP_KERNEL);
+ if (!pvt->vd)
+ return -ENOMEM;
+
+ k = 0;
+ for (i = 0; i < vm_num; i++) {
+ for (j = 0; j < vm_active_ch[i]; j++) {
+ pvt->vd[k].vm_map = vm_idx[i];
+ pvt->vd[k].ch_map = j;
+ k++;
+ }
+ }
+
+ return 0;
+}
+
static int mr75203_probe(struct platform_device *pdev)
{
u32 ts_num, vm_num, pd_num, ch_num, val, index, i;
@@ -574,7 +655,6 @@ static int mr75203_probe(struct platform_device *pdev)
pvt->t_num = ts_num;
pvt->p_num = pd_num;
pvt->v_num = vm_num;
- pvt->c_num = ch_num;
val = 0;
if (ts_num)
val++;
@@ -611,44 +691,41 @@ static int mr75203_probe(struct platform_device *pdev)
}

if (vm_num) {
- u32 total_ch;
+ u8 vm_idx[VM_NUM_MAX];

ret = pvt_get_regmap(pdev, "vm", pvt);
if (ret)
return ret;

- pvt->vm_idx = devm_kcalloc(dev, vm_num, sizeof(*pvt->vm_idx),
- GFP_KERNEL);
- if (!pvt->vm_idx)
- return -ENOMEM;
-
- ret = device_property_read_u8_array(dev, "intel,vm-map",
- pvt->vm_idx, vm_num);
+ ret = device_property_read_u8_array(dev, "intel,vm-map", vm_idx,
+ vm_num);
if (ret) {
/*
* Incase intel,vm-map property is not defined, we
* assume incremental channel numbers.
*/
for (i = 0; i < vm_num; i++)
- pvt->vm_idx[i] = i;
+ vm_idx[i] = i;
} else {
for (i = 0; i < vm_num; i++)
- if (pvt->vm_idx[i] >= vm_num ||
- pvt->vm_idx[i] == 0xff) {
+ if (vm_idx[i] >= vm_num || vm_idx[i] == 0xff) {
pvt->v_num = i;
vm_num = i;
break;
}
}

- total_ch = ch_num * vm_num;
- in_config = devm_kcalloc(dev, total_ch + 1,
+ ret = pvt_get_active_channel(dev, pvt, vm_num, ch_num, vm_idx);
+ if (ret)
+ return ret;
+
+ in_config = devm_kcalloc(dev, pvt->vm_channels.total + 1,
sizeof(*in_config), GFP_KERNEL);
if (!in_config)
return -ENOMEM;

- memset32(in_config, HWMON_I_INPUT, total_ch);
- in_config[total_ch] = 0;
+ memset32(in_config, HWMON_I_INPUT, pvt->vm_channels.total);
+ in_config[pvt->vm_channels.total] = 0;
pvt_in.config = in_config;

pvt_info[index++] = &pvt_in;
--
2.37.1