Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759999Ab3GSIfq (ORCPT ); Fri, 19 Jul 2013 04:35:46 -0400 Received: from exprod5og112.obsmtp.com ([64.18.0.24]:49672 "EHLO exprod5og112.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755412Ab3GSIfm (ORCPT ); Fri, 19 Jul 2013 04:35:42 -0400 MIME-Version: 1.0 In-Reply-To: <51E7B9DA.9040803@metafoo.de> References: <1374059564-6872-1-git-send-email-oleksandr.kozaruk@ti.com> <1374059564-6872-3-git-send-email-oleksandr.kozaruk@ti.com> <51E6DCB5.3070302@metafoo.de> <51E7B9DA.9040803@metafoo.de> Date: Fri, 19 Jul 2013 11:35:41 +0300 Message-ID: Subject: Re: [PATCH v5 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver From: Oleksandr Kozaruk To: Lars-Peter Clausen Cc: tony@atomide.com, benoit.cousson@linaro.org, rnayak@ti.com, peter.ujfalusi@ti.com, kishon@ti.com, jic23@cam.ac.uk, grant.likely@linaro.org, rob.herring@calxeda.com, sameo@linux.intel.com, ch.naveen@samsung.com, poeschel@lemonage.de, milo.kim@ti.com, balajitk@ti.com, gg@slimlogic.co.uk, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-omap@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8608 Lines: 246 Hello Lars, On Thu, Jul 18, 2013 at 12:48 PM, Lars-Peter Clausen wrote: > On 07/18/2013 10:36 AM, Oleksandr Kozaruk wrote: >> Hello Lars, >> >> On Wed, Jul 17, 2013 at 9:04 PM, Lars-Peter Clausen 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". > > The pattern is pretty regular though, how about: > > > int twl6032_get_trim_value(u8 *trim_regs, unsigned int reg0, > unsigned int reg1, unsigned int mask0, unsigned int mask1, > unsigned int shift0) > { > int val; > > val = (trim_regs[reg0] & mask0) << shift0; > val |= (trim_regs[reg1] & mask1) >> 1; > if (trim_regs[reg1] & 0x01) > val = -val; > > return val; > } > > and then > > d1 = twl6032_get_trim_value(trim_regs, 3, 1, 0x1f, 0x06, 2); > d2 = twl6032_get_trim_value(trim_regs, 4, 2, 0x3f, 0x06, 2); > > and so on. Thank you. I think legibility is better now, I even found a bug - in case 9 'break' was missing. Though it is not without special case for channels 7, 18: 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 = twl6032_get_trim_value(trim_regs, 3, 1, 0x1f, 0x06, 2); d2 = twl6032_get_trim_value(trim_regs, 4, 2, 0x3f, 0x06, 2); break; case 8: temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x1f, 0x06, 2); d1 = temp + twl6032_get_trim_value(trim_regs, 8, 7, 0x18, 0x1E, 1); temp = twl6032_get_trim_value(trim_regs, 4, 2, 0x3F, 0x06, 2); d2 = temp + twl6032_get_trim_value(trim_regs, 10, 8, 0x1F, 0x06, 2); break; case 9: temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x1f, 0x06, 2); d1 = temp + twl6032_get_trim_value(trim_regs, 14, 12, 0x18, 0x1E, 1); temp = twl6032_get_trim_value(trim_regs, 4, 2, 0x3f, 0x06, 2); d2 = temp + twl6032_get_trim_value(trim_regs, 16, 14, 0x1F, 0x06, 1); break; case 10: d1 = twl6032_get_trim_value(trim_regs, 11, 9, 0x0f, 0x0E, 3); d2 = twl6032_get_trim_value(trim_regs, 15, 13, 0x0f, 0x0E, 3); break; case 7: case 18: temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x1f, 0x06, 2); d1 = (trim_regs[5] & 0x7E) >> 1; if (trim_regs[5] & 0x01) d1 = -d1; d1 += temp; temp = twl6032_get_trim_value(trim_regs, 4, 2, 0x3f, 0x06, 2); d2 = (trim_regs[6] & 0xFE) >> 1; if (trim_regs[6] & 0x01) d2 = -d2; d2 += temp; break; default: /* No data for other channels */ continue; } -- Regards, Oleksandr Kozaruk -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/