Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758180Ab3GRJrc (ORCPT ); Thu, 18 Jul 2013 05:47:32 -0400 Received: from smtp-out-159.synserver.de ([212.40.185.159]:1463 "EHLO smtp-out-159.synserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758148Ab3GRJrZ (ORCPT ); Thu, 18 Jul 2013 05:47:25 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 9487 Message-ID: <51E7B9DA.9040803@metafoo.de> Date: Thu, 18 Jul 2013 11:48:10 +0200 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130704 Icedove/17.0.7 MIME-Version: 1.0 To: Oleksandr Kozaruk 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 Subject: Re: [PATCH v5 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver 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> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6571 Lines: 179 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. -- 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/