Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756670Ab0GEPoB (ORCPT ); Mon, 5 Jul 2010 11:44:01 -0400 Received: from mailhost.informatik.uni-hamburg.de ([134.100.9.70]:53952 "EHLO mailhost.informatik.uni-hamburg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754578Ab0GEPoA (ORCPT ); Mon, 5 Jul 2010 11:44:00 -0400 Message-ID: <4C31FDA3.3040708@metafoo.de> Date: Mon, 05 Jul 2010 17:43:31 +0200 From: Lars-Peter Clausen User-Agent: Mozilla-Thunderbird 2.0.0.24 (X11/20100329) MIME-Version: 1.0 To: Samuel Ortiz CC: Ralf Baechle , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 22/26] MFD: Add JZ4740 ADC driver References: <1276924111-11158-1-git-send-email-lars@metafoo.de> <1276924111-11158-23-git-send-email-lars@metafoo.de> <20100705145306.GA3850@sortiz-mobl> In-Reply-To: <20100705145306.GA3850@sortiz-mobl> X-Enigmail-Version: 0.95.0 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: 4326 Lines: 138 Hi Samuel Ortiz wrote: > Hi Lars, > > Sorry for the review delay. This one got lost in my inbox :-/ > > On Sat, Jun 19, 2010 at 07:08:27AM +0200, Lars-Peter Clausen wrote: >> This patch adds a MFD driver for the JZ4740 ADC unit. The driver is used to >> demultiplex IRQs and synchronize access to shared registers between the battery, >> hwmon and (future) touchscreen driver. > The driver looks pretty clean. I only have a couple nitpicks: > >> +static void jz4740_adc_irq_demux(unsigned int irq, struct irq_desc *desc) >> +{ >> + struct jz4740_adc *adc = get_irq_desc_data(desc); >> + uint8_t status; >> + unsigned int i; >> + >> + status = readb(adc->base + JZ_REG_ADC_STATUS); >> + >> + for (i = 0; i < 5; ++i) { >> + if (status & BIT(i)) >> + generic_handle_irq(adc->irq_base + i); > for_each_set_bit() could nicely replace your loop here. I wonder if it would make sense to optimize for_each_set_bit for small builtin constants. Using it in it's current form for this loop would likely add some overhead. > >> +static inline void jz4740_adc_clk_enable(struct jz4740_adc *adc) >> +{ >> + unsigned long flags; >> + >> + spin_lock_irqsave(&adc->lock, flags); >> + if (adc->clk_ref++ == 0) >> + clk_enable(adc->clk); >> + spin_unlock_irqrestore(&adc->lock, flags); >> +} > I'm not familiar with your platform clock framework, but shouldn't the > refcounting be handled there instead of spread over all your drivers ? The ADC clock is the only clock on this platform which is shared between multiple devices so I refrained from adding the refcounting to the core for now. But to be strictly complaint with the clock API as defined in linux/clk.h the implementation should do refcounting. I'm still a bit uncertain what would be done best here. > >> +static int __devinit jz4740_adc_probe(struct platform_device *pdev) >> +{ >> + int ret; >> + struct jz4740_adc *adc; >> + struct resource *mem_base; >> + int irq; >> + >> + adc = kmalloc(sizeof(*adc), GFP_KERNEL); >> + >> + adc->irq = platform_get_irq(pdev, 0); >> + if (adc->irq < 0) { >> + ret = adc->irq; >> + dev_err(&pdev->dev, "Failed to get platform irq: %d\n", ret); >> + goto err_free; >> + } >> + >> + adc->irq_base = platform_get_irq(pdev, 1); >> + if (adc->irq_base < 0) { >> + ret = adc->irq_base; >> + dev_err(&pdev->dev, "Failed to get irq base: %d\n", ret); >> + goto err_free; >> + } >> + >> + mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + if (!mem_base) { >> + ret = -ENOENT; >> + dev_err(&pdev->dev, "Failed to get platform mmio resource\n"); >> + goto err_free; >> + } >> + >> + /* Only request the shared registers for the MFD driver */ >> + adc->mem = request_mem_region(mem_base->start, JZ_REG_ADC_STATUS, >> + pdev->name); >> + if (!adc->mem) { >> + ret = -EBUSY; >> + dev_err(&pdev->dev, "Failed to request mmio memory region\n"); >> + goto err_free; >> + } >> + >> + adc->base = ioremap_nocache(adc->mem->start, resource_size(adc->mem)); >> + if (!adc->base) { >> + ret = -EBUSY; >> + dev_err(&pdev->dev, "Failed to ioremap mmio memory\n"); >> + goto err_release_mem_region; >> + } >> + >> + adc->clk = clk_get(&pdev->dev, "adc"); >> + if (IS_ERR(adc->clk)) { >> + ret = PTR_ERR(adc->clk); >> + dev_err(&pdev->dev, "Failed to get clock: %d\n", ret); >> + goto err_iounmap; >> + } >> + >> + spin_lock_init(&adc->lock); >> + >> + adc->clk_ref = 0; >> + >> + platform_set_drvdata(pdev, adc); >> + >> + for (irq = adc->irq_base; irq < adc->irq_base + 5; ++irq) { >> + set_irq_chip_data(irq, adc); >> + set_irq_chip_and_handler(irq, &jz4740_adc_irq_chip, >> + handle_level_irq); >> + } >> + >> + set_irq_data(adc->irq, adc); >> + set_irq_chained_handler(adc->irq, jz4740_adc_irq_demux); >> + >> + writeb(0x00, adc->base + JZ_REG_ADC_ENABLE); >> + writeb(0xff, adc->base + JZ_REG_ADC_CTRL); >> + >> + mfd_add_devices(&pdev->dev, 0, jz4740_adc_cells, >> + ARRAY_SIZE(jz4740_adc_cells), mem_base, adc->irq_base); >> + >> + return 0; > Please return the mfd_add_devices return value. > > Cheers, > Samuel. > Thanks for reviewing the patch - Lars -- 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/