From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Eugeniy Paltsev To: "sboyd@codeaurora.org" CC: "Eugeniy.Paltsev@synopsys.com" , "linux-kernel@vger.kernel.org" , "mark.rutland@arm.com" , "mturquette@baylibre.com" , "robh+dt@kernel.org" , "linux-clk@vger.kernel.org" , "linux-snps-arc@lists.infradead.org" Subject: Re: [PATCH] ARC: clk: introduce HSDKv1 pll driver Date: Wed, 9 Aug 2017 16:43:49 +0000 Message-ID: <1502297028.2586.4.camel@synopsys.com> References: <20170714153128.8945-1-Eugeniy.Paltsev@synopsys.com> <20170804015351.GW2146@codeaurora.org> In-Reply-To: <20170804015351.GW2146@codeaurora.org> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: SGkgU3RlcGhlbizCoA0KdGhhbmtzIGZvciByZXNwb25kLCBteSBjb21tZW50cyBhcmUgaW5saW5l ZCBiZWxvdy4NCg0KT24gVGh1LCAyMDE3LTA4LTAzIGF0IDE4OjUzIC0wNzAwLCBTdGVwaGVuIEJv eWQgd3JvdGU6DQo+IE9uIDA3LzE0LCBFdWdlbml5IFBhbHRzZXYgd3JvdGU6DQoNCj4gWy4uLl0N Cj4gPiArCWRldl9kYmcoY2xrLT5kZXYsICJ3cml0ZSBjb25maWd1cmFyaW9uOiAweCV4IiwgdmFs KTsNCj7CoA0KPiBPciBqdXN0IHVzZSAlI3ggdG8gYWRkIHRoZSAweCBwYXJ0Lg0KDQpUaGFua3Ms IEkgZG9uJ3Qga25vdyBhYm91dCB0aGlzIG9wdGlvbi4NCj7CoA0KPiBbLi4uXQ0KPg0KPiA+ICsJ LyogaW5wdXQgZGl2aWRlciA9IHJlZy5pZGl2ICsgMSAqLw0KPiA+ICsJaWRpdiA9IDEgKyAoKHZh bCAmIENHVV9QTExfQ1RSTF9JRElWX01BU0spID4+DQo+ID4gQ0dVX1BMTF9DVFJMX0lESVZfU0hJ RlQpOw0KPiA+ICsJLyogZmIgZGl2aWRlciA9IDIqKHJlZy5mYmRpdiArIDEpICovDQo+ID4gKwlm YmRpdiA9IDIgKiAoMSArICgodmFsICYgQ0dVX1BMTF9DVFJMX0ZCRElWX01BU0spID4+DQo+ID4g Q0dVX1BMTF9DVFJMX0ZCRElWX1NISUZUKSk7DQo+ID4gKwkvKiBvdXRwdXQgZGl2aWRlciA9IDJe KHJlZy5vZGl2KSAqLw0KPiA+ICsJb2RpdiA9IDEgPDwgKCh2YWwgJiBDR1VfUExMX0NUUkxfT0RJ Vl9NQVNLKSA+Pg0KPiA+IENHVV9QTExfQ1RSTF9PRElWX1NISUZUKTsNCj4NCj4gTWF5YmUganVz dCBkcm9wIHRoZXNlIGNvbW1lbnRzLiBUaGV5J3JlIGp1c3QgcmVwZWF0aW5nIHRoZSBjb2RlLg0K DQpBY3R1YWxseSBJIHdvdWxkIHByZWZlciB0byBrZWVwIHRoZW0sIGFzICIyXihyZWcub2Rpdiki IGlzIG1vcmXCoA0KaHVtYW4tcmVhZGFibGUgdGhlbg0KIjEgPDwgKCh2YWwgJiBDR1VfUExMX0NU UkxfT0RJVl9NQVNLKSA+PiBDR1VfUExMX0NUUkxfT0RJVl9TSElGVCkiDQoNCj4gPiArDQo+ID4g KwlyYXRlID0gKHU2NClwYXJlbnRfcmF0ZSAqIGZiZGl2Ow0KPiA+ICsJZG9fZGl2KHJhdGUsIGlk aXYgKiBvZGl2KTsNCj4gPiArDQo+ID4gKwlyZXR1cm4gcmF0ZTsNCj4gPiArfQ0KPiA+ICsNCj4g PiArc3RhdGljIGxvbmcgaHNka19wbGxfcm91bmRfcmF0ZShzdHJ1Y3QgY2xrX2h3ICpodywgdW5z aWduZWQgbG9uZw0KPiA+IHJhdGUsDQo+ID4gKwkJCQl1bnNpZ25lZCBsb25nICpwcmF0ZSkNCj4g PiArew0KPiA+ICsJaW50IGk7DQo+ID4gKwlsb25nIGJlc3RfcmF0ZTsNCj4gPiArCXN0cnVjdCBo c2RrX3BsbF9jbGsgKmNsayA9IHRvX2hzZGtfcGxsX2Nsayhodyk7DQo+ID4gKwljb25zdCBzdHJ1 Y3QgaHNka19wbGxfY2ZnICpwbGxfY2ZnID0gY2xrLT5wbGxfY2ZnOw0KPiA+ICsNCj4gPiArCWlm IChwbGxfY2ZnWzBdLnJhdGUgPT0gMCkNCj4gPiArCQlyZXR1cm4gLUVJTlZBTDsNCj7CoA0KPiBU aGlzIGhhcHBlbnM/DQoNCk9ubHkgaWYgd2UgYWRkIGJhZCBoc2RrX3BsbF9jZmcgdGFibGUuIEJ1 dCBpdCBpcyBxdWl0ZSBjb2xkIGNvZGUgLSB3ZQ0KY2hhbmdlIHBsbCBjb25maWd1cmF0aW9uIHF1 aXRlIHJhcmUsIHNvIG1heWJlIGl0J3MgYmV0dGVyIHRvIGtlZXAgdGhpcw0KYXNzZXJ0Pw0KDQo+ ID4gKw0KPiA+ICsJYmVzdF9yYXRlID0gcGxsX2NmZ1swXS5yYXRlOw0KPiA+ICsNCj4gPiArCWZv ciAoaSA9IDE7IHBsbF9jZmdbaV0ucmF0ZSAhPSAwOyBpKyspIHsNCj4gPiArCQlpZiAoYWJzKHJh dGUgLSBwbGxfY2ZnW2ldLnJhdGUpIDwgYWJzKHJhdGUgLQ0KPiA+IGJlc3RfcmF0ZSkpDQo+wqAN Cj4gQWxyaWdodCwgcmF0ZSBpcyB1bnNpZ25lZCBsb25nLCBhbmQgYmVzdF9yYXRlIGlzIGxvbmcu IGFicygpIGRvZXMNCj4gdGhlIHJpZ2h0IHRoaW5nIGhlcmUsIGJ1dCBpdCBtYWtlcyBtZSBoYXZl IHRvIHRoaW5rIHR3aWNlIGlmDQo+IGJlc3RfcmF0ZSBjYW4gYmUgbmVnYXRpdmUgYW5kIHRoZW4g dGhpcyBpcyBhIGxhcmdlciBudW1iZXIsIG5vdCBhDQo+IHNtYWxsZXIgb25lLiBDYW4gd2UgbWFr ZSBiZXN0X3JhdGUgdW5zaWduZWQgbG9uZyBpbiB0aGlzDQo+IGZ1bmN0aW9uPw0KDQpZZXMsIHdl IGNhbi4NCkFueXdheSBpdCdzIGEgYml0IHN0cmFuZ2Ugd2hhdCByYXRlIGlzIHVuc2lnbmVkIGxv bmcgYW5kIHJvdW5kX3JhdGUNCnJldHVybiB2YWx1ZSBpcyBsb25nLg0KLS3CoA0KwqBFdWdlbml5 IFBhbHRzZXY= From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeniy.Paltsev@synopsys.com (Eugeniy Paltsev) Date: Wed, 9 Aug 2017 16:43:49 +0000 Subject: [PATCH] ARC: clk: introduce HSDKv1 pll driver In-Reply-To: <20170804015351.GW2146@codeaurora.org> References: <20170714153128.8945-1-Eugeniy.Paltsev@synopsys.com> <20170804015351.GW2146@codeaurora.org> List-ID: Message-ID: <1502297028.2586.4.camel@synopsys.com> To: linux-snps-arc@lists.infradead.org Hi Stephen,? thanks for respond, my comments are inlined below. On Thu, 2017-08-03@18:53 -0700, Stephen Boyd wrote: > On 07/14, Eugeniy Paltsev wrote: > [...] > > + dev_dbg(clk->dev, "write configurarion: 0x%x", val); >? > Or just use %#x to add the 0x part. Thanks, I don't know about this option. >? > [...] > > > + /* input divider = reg.idiv + 1 */ > > + idiv = 1 + ((val & CGU_PLL_CTRL_IDIV_MASK) >> > > CGU_PLL_CTRL_IDIV_SHIFT); > > + /* fb divider = 2*(reg.fbdiv + 1) */ > > + fbdiv = 2 * (1 + ((val & CGU_PLL_CTRL_FBDIV_MASK) >> > > CGU_PLL_CTRL_FBDIV_SHIFT)); > > + /* output divider = 2^(reg.odiv) */ > > + odiv = 1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> > > CGU_PLL_CTRL_ODIV_SHIFT); > > Maybe just drop these comments. They're just repeating the code. Actually I would prefer to keep them, as "2^(reg.odiv)" is more? human-readable then "1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> CGU_PLL_CTRL_ODIV_SHIFT)" > > + > > + rate = (u64)parent_rate * fbdiv; > > + do_div(rate, idiv * odiv); > > + > > + return rate; > > +} > > + > > +static long hsdk_pll_round_rate(struct clk_hw *hw, unsigned long > > rate, > > + unsigned long *prate) > > +{ > > + int i; > > + long best_rate; > > + struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw); > > + const struct hsdk_pll_cfg *pll_cfg = clk->pll_cfg; > > + > > + if (pll_cfg[0].rate == 0) > > + return -EINVAL; >? > This happens? Only if we add bad hsdk_pll_cfg table. But it is quite cold code - we change pll configuration quite rare, so maybe it's better to keep this assert? > > + > > + best_rate = pll_cfg[0].rate; > > + > > + for (i = 1; pll_cfg[i].rate != 0; i++) { > > + if (abs(rate - pll_cfg[i].rate) < abs(rate - > > best_rate)) >? > Alright, rate is unsigned long, and best_rate is long. abs() does > the right thing here, but it makes me have to think twice if > best_rate can be negative and then this is a larger number, not a > smaller one. Can we make best_rate unsigned long in this > function? Yes, we can. Anyway it's a bit strange what rate is unsigned long and round_rate return value is long. --? ?Eugeniy Paltsev From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754152AbdHIQn4 (ORCPT ); Wed, 9 Aug 2017 12:43:56 -0400 Received: from smtprelay.synopsys.com ([198.182.47.9]:38064 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754094AbdHIQny (ORCPT ); Wed, 9 Aug 2017 12:43:54 -0400 From: Eugeniy Paltsev To: "sboyd@codeaurora.org" CC: "Eugeniy.Paltsev@synopsys.com" , "linux-kernel@vger.kernel.org" , "mark.rutland@arm.com" , "mturquette@baylibre.com" , "robh+dt@kernel.org" , "linux-clk@vger.kernel.org" , "linux-snps-arc@lists.infradead.org" Subject: Re: [PATCH] ARC: clk: introduce HSDKv1 pll driver Thread-Topic: [PATCH] ARC: clk: introduce HSDKv1 pll driver Thread-Index: AQHS/LZINI4LGuHFdUST8YjIoa4l+6JzbhaAgAjUTgA= Date: Wed, 9 Aug 2017 16:43:49 +0000 Message-ID: <1502297028.2586.4.camel@synopsys.com> References: <20170714153128.8945-1-Eugeniy.Paltsev@synopsys.com> <20170804015351.GW2146@codeaurora.org> In-Reply-To: <20170804015351.GW2146@codeaurora.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.121.3.11] Content-Type: text/plain; charset="utf-8" Content-ID: <8ED84AD976AC8F4FBDB3BBE6B64FC203@internal.synopsys.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v79Gi3Cs001695 Hi Stephen,  thanks for respond, my comments are inlined below. On Thu, 2017-08-03 at 18:53 -0700, Stephen Boyd wrote: > On 07/14, Eugeniy Paltsev wrote: > [...] > > + dev_dbg(clk->dev, "write configurarion: 0x%x", val); >  > Or just use %#x to add the 0x part. Thanks, I don't know about this option. >  > [...] > > > + /* input divider = reg.idiv + 1 */ > > + idiv = 1 + ((val & CGU_PLL_CTRL_IDIV_MASK) >> > > CGU_PLL_CTRL_IDIV_SHIFT); > > + /* fb divider = 2*(reg.fbdiv + 1) */ > > + fbdiv = 2 * (1 + ((val & CGU_PLL_CTRL_FBDIV_MASK) >> > > CGU_PLL_CTRL_FBDIV_SHIFT)); > > + /* output divider = 2^(reg.odiv) */ > > + odiv = 1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> > > CGU_PLL_CTRL_ODIV_SHIFT); > > Maybe just drop these comments. They're just repeating the code. Actually I would prefer to keep them, as "2^(reg.odiv)" is more  human-readable then "1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> CGU_PLL_CTRL_ODIV_SHIFT)" > > + > > + rate = (u64)parent_rate * fbdiv; > > + do_div(rate, idiv * odiv); > > + > > + return rate; > > +} > > + > > +static long hsdk_pll_round_rate(struct clk_hw *hw, unsigned long > > rate, > > + unsigned long *prate) > > +{ > > + int i; > > + long best_rate; > > + struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw); > > + const struct hsdk_pll_cfg *pll_cfg = clk->pll_cfg; > > + > > + if (pll_cfg[0].rate == 0) > > + return -EINVAL; >  > This happens? Only if we add bad hsdk_pll_cfg table. But it is quite cold code - we change pll configuration quite rare, so maybe it's better to keep this assert? > > + > > + best_rate = pll_cfg[0].rate; > > + > > + for (i = 1; pll_cfg[i].rate != 0; i++) { > > + if (abs(rate - pll_cfg[i].rate) < abs(rate - > > best_rate)) >  > Alright, rate is unsigned long, and best_rate is long. abs() does > the right thing here, but it makes me have to think twice if > best_rate can be negative and then this is a larger number, not a > smaller one. Can we make best_rate unsigned long in this > function? Yes, we can. Anyway it's a bit strange what rate is unsigned long and round_rate return value is long. --   Eugeniy Paltsev