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Message-ID: <CAPb7_muAzO-jRqgcm89fcKT-hTLq38Aj2p0WAWjGjN9DoQUwPg@mail.gmail.com>
Date: Thu, 18 Jul 2013 11:36:42 +0300
From: Oleksandr Kozaruk <oleksandr.kozaruk@...com>
To: Lars-Peter Clausen <lars@...afoo.de>
Cc: tony@...mide.com, benoit.cousson@...aro.org, rnayak@...com,
peter.ujfalusi@...com, kishon@...com, jic23@....ac.uk,
grant.likely@...aro.org, rob.herring@...xeda.com,
sameo@...ux.intel.com, ch.naveen@...sung.com, poeschel@...onage.de,
milo.kim@...com, balajitk@...com, gg@...mlogic.co.uk,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-iio@...r.kernel.org, devicetree-discuss@...ts.ozlabs.org,
linux-omap@...r.kernel.org
Subject: Re: [PATCH v5 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver
Hello Lars,
On Wed, Jul 17, 2013 at 9:04 PM, Lars-Peter Clausen <lars@...afoo.de> wrote:
>> +static int twl6032_calibration(struct twl6030_gpadc_data *gpadc)
>> +{
>> + int chn, d1 = 0, d2 = 0, temp;
>> + u8 trim_regs[17];
>> + int ret;
>> +
>> + ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs + 1,
>> + TWL6030_GPADC_TRIM1, 16);
>> + if (ret < 0) {
>> + dev_err(gpadc->dev, "calibration failed\n");
>> + return ret;
>> + }
>> +
>> + /*
>> + * Loop to calculate the value needed for returning voltages from
>> + * GPADC not values.
>> + *
>> + * gain is calculated to 3 decimal places fixed point.
>> + */
>> + for (chn = 0; chn < TWL6032_GPADC_MAX_CHANNELS; chn++) {
>> +
>> + switch (chn) {
>> + case 0:
>> + case 1:
>> + case 2:
>> + case 3:
>> + case 4:
>> + case 5:
>> + case 6:
>> + case 11:
>> + case 12:
>> + case 13:
>> + case 14:
>> + /* D1 */
>> + d1 = (trim_regs[3] & 0x1F) << 2;
>> + d1 |= (trim_regs[1] & 0x06) >> 1;
>> + if (trim_regs[1] & 0x01)
>> + d1 = -d1;
>> +
>> + /* D2 */
>> + d2 = (trim_regs[4] & 0x3F) << 2;
>> + d2 |= (trim_regs[2] & 0x06) >> 1;
>> + if (trim_regs[2] & 0x01)
>> + d2 = -d2;
>> + break;
>> + case 8:
>> + /* D1 */
>> + temp = (trim_regs[3] & 0x1F) << 2;
>> + temp |= (trim_regs[1] & 0x06) >> 1;
>> + if (trim_regs[1] & 0x01)
>> + temp = -temp;
>> +
>> + d1 = (trim_regs[8] & 0x18) << 1;
>> + d1 |= (trim_regs[7] & 0x1E) >> 1;
>> + if (trim_regs[7] & 0x01)
>> + d1 = -d1;
>> +
>> + d1 += temp;
>> +
>> + /* D2 */
>> + temp = (trim_regs[4] & 0x3F) << 2;
>> + temp |= (trim_regs[2] & 0x06) >> 1;
>> + if (trim_regs[2] & 0x01)
>> + temp = -temp;
>> +
>> + d2 = (trim_regs[10] & 0x1F) << 2;
>> + d2 |= (trim_regs[8] & 0x06) >> 1;
>> + if (trim_regs[8] & 0x01)
>> + d2 = -d2;
>> +
>> + d2 += temp;
>> + break;
>> + case 9:
>> + /* D1 */
>> + temp = (trim_regs[3] & 0x1F) << 2;
>> + temp |= (trim_regs[1] & 0x06) >> 1;
>> + if (trim_regs[1] & 0x01)
>> + temp = -temp;
>> +
>> + d1 = (trim_regs[14] & 0x18) << 1;
>> + d1 |= (trim_regs[12] & 0x1E) >> 1;
>> + if (trim_regs[12] & 0x01)
>> + d1 = -d1;
>> +
>> + d1 += temp;
>> +
>> + /* D2 */
>> + temp = (trim_regs[4] & 0x3F) << 2;
>> + temp |= (trim_regs[2] & 0x06) >> 1;
>> + if (trim_regs[2] & 0x01)
>> + temp = -temp;
>> +
>> + d2 = (trim_regs[16] & 0x1F) << 2;
>> + d2 |= (trim_regs[14] & 0x06) >> 1;
>> + if (trim_regs[14] & 0x01)
>> + d2 = -d2;
>> +
>> + d2 += temp;
>> + case 10:
>> + /* D1 */
>> + d1 = (trim_regs[11] & 0x0F) << 3;
>> + d1 |= (trim_regs[9] & 0x0E) >> 1;
>> + if (trim_regs[9] & 0x01)
>> + d1 = -d1;
>> +
>> + /* D2 */
>> + d2 = (trim_regs[15] & 0x0F) << 3;
>> + d2 |= (trim_regs[13] & 0x0E) >> 1;
>> + if (trim_regs[13] & 0x01)
>> + d2 = -d2;
>> + break;
>> + case 7:
>> + case 18:
>> + /* D1 */
>> + temp = (trim_regs[3] & 0x1F) << 2;
>> + temp |= (trim_regs[1] & 0x06) >> 1;
>> + if (trim_regs[1] & 0x01)
>> + temp = -temp;
>> +
>> + d1 = (trim_regs[5] & 0x7E) >> 1;
>> + if (trim_regs[5] & 0x01)
>> + d1 = -d1;
>> +.
>> + d1 += temp;
>> +
>> + /* D2 */
>> + temp = (trim_regs[4] & 0x3F) << 2;
>> + temp |= (trim_regs[2] & 0x06) >> 1;
>> + if (trim_regs[2] & 0x01)
>> + temp = -temp;
>> +
>> + d2 = (trim_regs[6] & 0xFE) >> 1;
>> + if (trim_regs[6] & 0x01)
>> + d2 = -d2;
>> +
>> + d2 += temp;
>> + break;
>
>
> There is quite a bit of copy paste in here. Putting the bit swizziling into
> a helper function should also improbe legibility.
Trimming bits are scattered randomly between registers and in
different bit positions.
I don't see any commonalities, that could be generalized. as Graeme
said about it "it's a bane of my life".
Regards,
OK.
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