Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754295AbbBJJWw (ORCPT ); Tue, 10 Feb 2015 04:22:52 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:55865 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752530AbbBJJWs (ORCPT ); Tue, 10 Feb 2015 04:22:48 -0500 X-Listener-Flag: 11101 Subject: Re: [PATCH 1/7] pinctrl: mediatek: emulate GPIO interrupt on both-edges From: Yingjoe Chen To: Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= CC: Chaotian Jing , Rob Herring , Matthias Brugger , Chris Ball , Ulf Hansson , Linus Walleij , Mark Rutland , James Liao , , Arnd Bergmann , , Hongzhou Yang , Catalin Marinas , , Will Deacon , , , Sascha Hauer , Eddie Huang , , In-Reply-To: <20150210084021.GM10842@pengutronix.de> References: <1422339332-27498-1-git-send-email-chaotian.jing@mediatek.com> <1422339332-27498-2-git-send-email-chaotian.jing@mediatek.com> <20150210084021.GM10842@pengutronix.de> Content-Type: text/plain; charset="UTF-8" Date: Tue, 10 Feb 2015 17:22:41 +0800 Message-ID: <1423560161.24705.15.camel@mtksdaap41> MIME-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 8bit X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2992 Lines: 92 On Tue, 2015-02-10 at 09:40 +0100, Uwe Kleine-König wrote: > Hello, > > On Tue, Jan 27, 2015 at 02:15:26PM +0800, Chaotian Jing wrote: > > From: Yingjoe Chen > > > > MTK EINT does not support generating interrupt on both edges. > > Emulate this by changing edge polarity while enable irq, > > set types and interrupt handling. This follows an example of > > drivers/gpio/gpio-mxc.c. <...> > > +static int mtk_eint_flip_edge(struct mtk_pinctrl *pctl, int hwirq) > > +{ > > + int start_level, curr_level; > > + unsigned int reg_offset; > > + const struct mtk_eint_offsets *eint_offsets = &(pctl->devdata->eint_offsets); > > + u32 mask = 1 << (hwirq & 0x1f); > > + u32 port = (hwirq >> 5) & eint_offsets->port_mask; > > + void __iomem *reg = pctl->eint_reg_base + (port << 2); > > + const struct mtk_desc_pin *pin; > > + > > + pin = mtk_find_pin_by_eint_num(pctl, hwirq); > > + curr_level = mtk_gpio_get(pctl->chip, pin->pin.number); > > + do { > > + start_level = curr_level; > > + if (start_level) > > + reg_offset = eint_offsets->pol_clr; > > + else > > + reg_offset = eint_offsets->pol_set; > > + writel(mask, reg + reg_offset); > > + > > + curr_level = mtk_gpio_get(pctl->chip, pin->pin.number); > > + } while (start_level != curr_level); > > + > > + return start_level; > > +} > > + > > static void mtk_eint_mask(struct irq_data *d) > > { > > struct mtk_pinctrl *pctl = irq_data_get_irq_chip_data(d); > > @@ -814,6 +840,9 @@ static void mtk_eint_unmask(struct irq_data *d) > > eint_offsets->mask_clr); > > > > writel(mask, reg); > > + > > + if (pctl->eint_dual_edges[d->hwirq]) > > + mtk_eint_flip_edge(pctl, d->hwirq); > > } > From looking at the code it seems to me that there is a bug. Consider > the following to happen: > > pin changes level, say high to low, triggers irq > > irq is masked by writel(mask, reg) in mtk_eint_mask > > mtk_eint_flip_edge gets curr_level = low > > pin goes up > > writel(mask, reg + eint_offsets->pol_set); > > oh, pin is high, so: writel(mask, reg + eint_offsets->pol_clr > > So now you trigger the irq the next time when the pin goes down again. > But that means to missed to trigger on the "pin goes up" in the above > list, right? Hi Uwe, Yes, this could be a problem when irq happen. So I fix/workaround this in mtk_eint_irq_handler() using soft-irq. When this bit is set, eint will trigger the same interrupt again. + if (dual_edges) { + curr_level = mtk_eint_flip_edge(pctl, index); + + /* If level changed, we might lost one edge + interrupt, raised it through soft-irq */ + if (start_level != curr_level) + writel(BIT(offset), reg - + eint_offsets->stat + + eint_offsets->soft_set); + } Joe.C -- 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/