Messages in this thread | | | Subject | Re: [PATCH v3 02/19] hwmon: (mr75203) fix VM sensor allocation when "intel, vm-map" not defined | Date | Thu, 1 Sep 2022 11:39:58 +0300 | From | "Farber, Eliav" <> |
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On 8/31/2022 2:48 PM, Guenter Roeck wrote: > On 8/30/22 22:49, Farber, Eliav wrote: >> On 8/31/2022 8:36 AM, Guenter Roeck wrote: >>> On 8/30/22 12:21, Eliav Farber wrote: >>>> Bug fix - in case "intel,vm-map" is missing in device-tree ,'num' >>>> is set >>>> to 0, and no voltage channel infos are allocated. >>>> >>>> Signed-off-by: Eliav Farber <farbere@amazon.com> >>>> --- >>>> drivers/hwmon/mr75203.c | 28 ++++++++++++---------------- >>>> 1 file changed, 12 insertions(+), 16 deletions(-) >>>> >>>> diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c >>>> index 046523d47c29..0e29877a1a9c 100644 >>>> --- a/drivers/hwmon/mr75203.c >>>> +++ b/drivers/hwmon/mr75203.c >>>> @@ -580,8 +580,6 @@ static int mr75203_probe(struct platform_device >>>> *pdev) >>>> } >>>> >>>> if (vm_num) { >>>> - u32 num = vm_num; >>>> - >>>> ret = pvt_get_regmap(pdev, "vm", pvt); >>>> if (ret) >>>> return ret; >>>> @@ -594,30 +592,28 @@ static int mr75203_probe(struct >>>> platform_device *pdev) >>>> ret = device_property_read_u8_array(dev, "intel,vm-map", >>>> pvt->vm_idx, vm_num); >>>> if (ret) { >>>> - num = 0; >>>> + /* >>>> + * 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; >>>> } else { >>>> for (i = 0; i < vm_num; i++) >>>> if (pvt->vm_idx[i] >= vm_num || >>>> - pvt->vm_idx[i] == 0xff) { >>>> - num = i; >>>> + pvt->vm_idx[i] == 0xff) >>>> break; >>> >>> So all vm_idx values from 0x00 to 0xfe would be acceptable ? >>> Does the chip really have that many registers (0x200 + 0x40 + 0x200 >>> * 0xfe) ? >>> Is that documented somewhere ? >> According to the code vm_num is limited to 32 because the mask is >> only 5 bits: >> >> #define VM_NUM_MSK GENMASK(20, 16) >> #define VM_NUM_SFT 16 >> vm_num = (val & VM_NUM_MSK) >> VM_NUM_SFT; >> >> In practice according to the data sheet I have: >> 0 <= VM instances <= 8 >> > Sorry, my bad. I misread the patch and thought the first part of > the if statement was removed. > > Anyway, what is the difference between specifying an vm_idx value of > 0xff and not specifying anything ? Or, in other words, taking the dt > example, the difference between > intel,vm-map = [03 01 04 ff ff]; > and > intel,vm-map = [03 01 04];
The actual number of VMs is read from a HW register: ret = regmap_read(pvt->c_map, PVT_IP_CONFIG, &val); ... vm_num = (val & VM_NUM_MSK) >> VM_NUM_SFT;
Also, using: ret = device_property_read_u8_array(dev, "intel,vm-map", vm_idx, vm_num); in the driver will fail if vm_num > sizeof array in device-tree.
So, if for example vm_num = 5, but you will want to map only 3 of them you most set property to be: intel,vm-map = [03 01 04 ff ff]; otherwise if you set: intel,vm-map = [03 01 04]; it will assume the property doesn't, and will continue the flow in code as if it doesn’t exist (which is not what the user wanted, and before my fix also has a bug).
-- Regards, Eliav
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