From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from gofer.mess.org ([80.229.237.210]:33041 "EHLO gofer.mess.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S969065AbdAERMr (ORCPT ); Thu, 5 Jan 2017 12:12:47 -0500 Date: Thu, 5 Jan 2017 17:12:40 +0000 From: Sean Young To: sean.wang@mediatek.com Cc: mchehab@osg.samsung.com, hdegoede@redhat.com, hkallweit1@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com, matthias.bgg@gmail.com, andi.shyti@samsung.com, hverkuil@xs4all.nl, ivo.g.dimitrov.75@gmail.com, linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, keyhaede@gmail.com Subject: Re: [PATCH 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC Message-ID: <20170105171240.GA9136@gofer.mess.org> References: <1483632384-8107-1-git-send-email-sean.wang@mediatek.com> <1483632384-8107-3-git-send-email-sean.wang@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1483632384-8107-3-git-send-email-sean.wang@mediatek.com> Sender: linux-media-owner@vger.kernel.org List-ID: Hi Sean, Some review comments. On Fri, Jan 06, 2017 at 12:06:24AM +0800, sean.wang@mediatek.com wrote: > From: Sean Wang > > This patch adds driver for IR controller on > Mediatek MT7623 SoC. Currently testing successfully > on NEC and SONY remote controller only but it should > work on others (lirc, rc-5 and rc-6). > > Signed-off-by: Sean Wang > --- > drivers/media/rc/Kconfig | 10 ++ > drivers/media/rc/Makefile | 1 + > drivers/media/rc/mtk-cir.c | 319 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 330 insertions(+) > create mode 100644 linux-4.8.rc1_p0/drivers/media/rc/mtk-cir.c > > diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig > index 370e16e..626c500 100644 > --- a/drivers/media/rc/Kconfig > +++ b/drivers/media/rc/Kconfig > @@ -389,4 +389,14 @@ config IR_SUNXI > To compile this driver as a module, choose M here: the module will > be called sunxi-ir. > > +config IR_MTK > + tristate "Mediatek IR remote control" > + depends on RC_CORE > + depends on ARCH_MEDIATEK || COMPILE_TEST > + ---help--- > + Say Y if you want to use Mediatek internal IR Controller > + > + To compile this driver as a module, choose M here: the module will > + be called mtk-cir. > + > endif #RC_DEVICES > diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile > index 379a5c0..505908d 100644 > --- a/drivers/media/rc/Makefile > +++ b/drivers/media/rc/Makefile > @@ -37,3 +37,4 @@ obj-$(CONFIG_IR_TTUSBIR) += ttusbir.o > obj-$(CONFIG_RC_ST) += st_rc.o > obj-$(CONFIG_IR_SUNXI) += sunxi-cir.o > obj-$(CONFIG_IR_IMG) += img-ir/ > +obj-$(CONFIG_IR_MTK) += mtk-cir.o > diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c > new file mode 100644 > index 0000000..4fa4cab > --- /dev/null > +++ b/drivers/media/rc/mtk-cir.c > @@ -0,0 +1,319 @@ > +/* > + * Driver for Mediatek MT7623 IR Receiver Controller > + * > + * Copyright (C) 2017 Sean Wang > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation; either version 2 of > + * the License, or (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define MTK_IR_DEV "mtk-ir" KBUILD_MODNAME could be used instead. Currently the module is called mtk-cir but the rc device will have driver name mtk-ir. > + > +/* Register to enable PWM and IR */ > +#define MTK_CONFIG_HIGH_REG 0x0c > +/* Enable IR pulse width detection */ > +#define MTK_PWM_EN BIT(13) > +/* Enable IR hardware function */ > +#define MTK_IR_EN BIT(0) > + > +/* Register to setting sample period */ > +#define MTK_CONFIG_LOW_REG 0x10 > +/* Field to set sample period */ > +#define CHK_PERIOD 0xC00 > +#define MTK_CHK_PERIOD (((CHK_PERIOD) << 8) & (GENMASK(20, 8))) > +#define MTK_CHK_PERIOD_MASK (GENMASK(20, 8)) > + > +/* Register to clear state of state machine */ > +#define MTK_IRCLR_REG 0x20 > +/* Bit to restart IR receiving */ > +#define MTK_IRCLR BIT(0) > + > +/* Register containing pulse width data */ > +#define MTK_CHKDATA_REG(i) (0x88 + 4 * i) > + > +/* Register to enable IR interrupt */ > +#define MTK_IRINT_EN_REG 0xcc > +/* Bit to enable interrupt */ > +#define MTK_IRINT_EN BIT(0) > + > +/* Register to ack IR interrupt */ > +#define MTK_IRINT_CLR_REG 0xd0 > +/* Bit to clear interrupt status */ > +#define MTK_IRINT_CLR BIT(0) > + > +/* Number of registers to record the pulse width */ > +#define MTK_CHKDATA_SZ 17 > +/* Required frequency */ > +#define MTK_IR_BASE_CLK 273000000 > +/* Frequency after IR internal divider */ > +#define MTK_IR_CLK (MTK_IR_BASE_CLK / 4) > +/* Sample period in ns */ > +#define MTK_IR_SAMPLE (((1000000000ul / MTK_IR_CLK) * CHK_PERIOD)) > +/* Indicate the end of IR data*/ > +#define MTK_IR_END(v) (v == 0xff) > + > +/* struct mtk_ir - This is the main datasructure for holding the state > + * of the driver > + * @dev: The device pointer > + * @ir_lock: Make sure that synchronization between remove and ISR > + * @rc: The rc instrance > + * @base: The mapped register i/o base > + * @irq: The IRQ that we are using > + * @clk: The clock that we are using > + * @map_name: The name for keymap lookup > + */ > +struct mtk_ir { > + struct device *dev; > + /*Protect concurrency between driver removal and ISR*/ > + spinlock_t ir_lock; > + struct rc_dev *rc; > + void __iomem *base; > + int irq; > + struct clk *clk; > + const char *map_name; irq and map_name don't need to be stored here, they're only used in mtk_ir_probe. > +}; > + > +static void mtk_w32_mask(struct mtk_ir *ir, u32 val, u32 mask, unsigned int reg) > +{ > + u32 tmp; > + > + tmp = __raw_readl(ir->base + reg); > + tmp = (tmp & ~mask) | val; > + __raw_writel(tmp, ir->base + reg); > +} > + > +static void mtk_w32(struct mtk_ir *ir, u32 val, unsigned int reg) > +{ > + __raw_writel(val, ir->base + reg); > +} > + > +static u32 mtk_r32(struct mtk_ir *ir, unsigned int reg) > +{ > + return __raw_readl(ir->base + reg); > +} > + > +static inline void mtk_irq_disable(struct mtk_ir *ir, u32 mask) > +{ > + u32 val; > + > + val = mtk_r32(ir, MTK_IRINT_EN_REG); > + mtk_w32(ir, val & ~mask, MTK_IRINT_EN_REG); > +} > + > +static inline void mtk_irq_enable(struct mtk_ir *ir, u32 mask) > +{ > + u32 val; > + > + val = mtk_r32(ir, MTK_IRINT_EN_REG); > + mtk_w32(ir, val | mask, MTK_IRINT_EN_REG); > +} > + > +static irqreturn_t mtk_ir_irq(int irqno, void *dev_id) > +{ > + struct mtk_ir *ir = dev_id; > + u8 wid = 0; > + u32 i, j, val; > + DEFINE_IR_RAW_EVENT(rawir); > + > + spin_lock(&ir->ir_lock); > + > + mtk_irq_disable(ir, MTK_IRINT_EN); > + > + /* Reset decoder state machine */ > + ir_raw_event_reset(ir->rc); > + > + /* First message must be pulse */ > + rawir.pulse = false; > + > + /* Handle pulse and space until end of message */ > + for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) { > + val = mtk_r32(ir, MTK_CHKDATA_REG(i)); > + dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val); > + > + for (j = 0 ; j < 4 ; j++) { > + wid = (val & (0xff << j * 8)) >> j * 8; > + rawir.pulse = !rawir.pulse; > + rawir.duration = wid * (MTK_IR_SAMPLE + 1); > + ir_raw_event_store_with_filter(ir->rc, &rawir); > + > + if (MTK_IR_END(wid)) > + goto end_msg; > + } > + } If I read this correctly, there is a maximum of 17 * 4 = 68 edges per IR message. The rc6 mce key 0 (scancode 0x800f0400) is 69 edges, so that won't work. > +end_msg: > + /* Restart the next receive */ > + mtk_w32_mask(ir, 0x1, MTK_IRCLR, MTK_IRCLR_REG); > + > + ir_raw_event_set_idle(ir->rc, true); > + ir_raw_event_handle(ir->rc); > + > + /* Clear interrupt status */ > + mtk_w32_mask(ir, 0x1, MTK_IRINT_CLR, MTK_IRINT_CLR_REG); > + > + /* Enable interrupt */ > + mtk_irq_enable(ir, MTK_IRINT_EN); > + > + spin_unlock(&ir->ir_lock); > + > + return IRQ_HANDLED; > +} > + > +static int mtk_ir_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct device_node *dn = dev->of_node; > + struct resource *res; > + struct mtk_ir *ir; > + u32 val; > + int ret = 0; > + > + ir = devm_kzalloc(dev, sizeof(struct mtk_ir), GFP_KERNEL); > + if (!ir) > + return -ENOMEM; > + > + spin_lock_init(&ir->ir_lock); > + > + ir->dev = dev; > + > + if (!of_device_is_compatible(dn, "mediatek,mt7623-ir")) > + return -ENODEV; > + > + ir->clk = devm_clk_get(dev, "clk"); > + if (IS_ERR(ir->clk)) { > + dev_err(dev, "failed to get a ir clock.\n"); > + return PTR_ERR(ir->clk); > + } > + > + if (clk_prepare_enable(ir->clk)) { > + dev_err(dev, "try to enable ir_clk failed\n"); > + ret = -EINVAL; > + goto exit_clkdisable_clk; > + } > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + ir->base = devm_ioremap_resource(dev, res); > + if (IS_ERR(ir->base)) { > + dev_err(dev, "failed to map registers\n"); > + ret = PTR_ERR(ir->base); > + goto exit_clkdisable_clk; > + } > + > + ir->rc = rc_allocate_device(); > + if (!ir->rc) { > + dev_err(dev, "failed to allocate device\n"); > + ret = -ENOMEM; > + goto exit_clkdisable_clk; > + } > + > + ir->rc->priv = ir; > + ir->rc->input_name = MTK_IR_DEV; > + ir->rc->input_phys = "mtk-ir/input0"; > + ir->rc->input_id.bustype = BUS_HOST; > + ir->rc->input_id.vendor = 0x0001; > + ir->rc->input_id.product = 0x0001; > + ir->rc->input_id.version = 0x0001; > + ir->map_name = of_get_property(dn, "linux,rc-map-name", NULL); > + ir->rc->map_name = ir->map_name ?: RC_MAP_EMPTY; > + ir->rc->dev.parent = dev; > + ir->rc->driver_type = RC_DRIVER_IR_RAW; > + ir->rc->driver_name = MTK_IR_DEV; > + ir->rc->allowed_protocols = RC_BIT_ALL; > + ir->rc->rx_resolution = MTK_IR_SAMPLE; > + > + ret = rc_register_device(ir->rc); > + if (ret) { > + dev_err(dev, "failed to register rc device\n"); > + goto exit_free_dev; > + } > + > + platform_set_drvdata(pdev, ir); > + > + ir->irq = platform_get_irq(pdev, 0); > + if (ir->irq < 0) { > + dev_err(dev, "no irq resource\n"); > + ret = ir->irq; >>From here on onwards the errors paths should call rc_unregister_device(), and no longer call rc_free_device(). Note that current master has devm_rc_allocate_device() and devm_rc_register_device() which would simplify this code. > + goto exit_free_dev; > + } > + > + ret = devm_request_irq(dev, ir->irq, mtk_ir_irq, 0, MTK_IR_DEV, ir); > + if (ret) { > + dev_err(dev, "failed request irq\n"); > + goto exit_free_dev; > + } > + > + mtk_irq_disable(ir, MTK_IRINT_EN); > + > + val = mtk_r32(ir, MTK_CONFIG_HIGH_REG); > + val |= MTK_PWM_EN | MTK_IR_EN; > + mtk_w32(ir, val, MTK_CONFIG_HIGH_REG); > + > + /* Setting sample period */ > + mtk_w32_mask(ir, MTK_CHK_PERIOD, MTK_CHK_PERIOD_MASK, > + MTK_CONFIG_LOW_REG); > + > + mtk_irq_enable(ir, MTK_IRINT_EN); > + > + dev_info(dev, "initialized MT7623 IR driver\n"); > + return 0; > + > +exit_free_dev: > + rc_free_device(ir->rc); > +exit_clkdisable_clk: > + clk_disable_unprepare(ir->clk); > + > + return ret; > +} > + > +static int mtk_ir_remove(struct platform_device *pdev) > +{ > + unsigned long flags; > + > + struct mtk_ir *ir = platform_get_drvdata(pdev); > + > + spin_lock_irqsave(&ir->ir_lock, flags); > + > + mtk_irq_disable(ir, MTK_IRINT_EN); > + > + clk_disable_unprepare(ir->clk); > + > + spin_unlock_irqrestore(&ir->ir_lock, flags); I'm not convinced the ir_lock is helping to prevent any race condition. An irq might still already have occurred which will now try to use ir->rc which is freed. You can remove the spinlock completely and call sychronize_irq() after disabling the mtk interrupt. That way you're sure the remove is safe to complete. > + > + rc_unregister_device(ir->rc); > + > + return 0; > +} > + > +static const struct of_device_id mtk_ir_match[] = { > + { .compatible = "mediatek,mt7623-ir" }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, mtk_ir_match); > + > +static struct platform_driver mtk_ir_driver = { > + .probe = mtk_ir_probe, > + .remove = mtk_ir_remove, > + .driver = { > + .name = MTK_IR_DEV, > + .of_match_table = mtk_ir_match, > + }, > +}; > + > +module_platform_driver(mtk_ir_driver); > + > +MODULE_DESCRIPTION("Mediatek MT7623 IR Receiver Controller Driver"); > +MODULE_AUTHOR("Sean Wang "); > +MODULE_LICENSE("GPL"); > -- > 1.9.1 >