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[81.169.180.215]) by mx.google.com with ESMTP id 25-v6si7564094edu.218.2018.08.09.07.01.42; Thu, 09 Aug 2018 07:01:42 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of u-boot-bounces@lists.denx.de designates 81.169.180.215 as permitted sender) client-ip=81.169.180.215; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of u-boot-bounces@lists.denx.de designates 81.169.180.215 as permitted sender) smtp.mailfrom=u-boot-bounces@lists.denx.de Received: by lists.denx.de (Postfix, from userid 105) id 5C4F7C21DED; Thu, 9 Aug 2018 14:00:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lists.denx.de X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=unavailable autolearn_force=no version=3.4.0 Received: from lists.denx.de (localhost [IPv6:::1]) by lists.denx.de (Postfix) with ESMTP id 42563C21DFA; Thu, 9 Aug 2018 13:59:25 +0000 (UTC) Received: by lists.denx.de (Postfix, from userid 105) id BDD89C21C27; Thu, 9 Aug 2018 13:59:21 +0000 (UTC) Received: from esa2.microchip.iphmx.com (esa2.microchip.iphmx.com [68.232.149.84]) by lists.denx.de (Postfix) with ESMTPS id E5AC2C21BE5 for ; Thu, 9 Aug 2018 13:59:20 +0000 (UTC) X-IronPort-AV: E=Sophos;i="5.53,215,1531810800"; d="scan'208";a="17647520" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa2.microchip.iphmx.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 09 Aug 2018 06:59:20 -0700 Received: from eh-station.mchp-main.com (10.10.76.4) by chn-sv-exch07.mchp-main.com (10.10.76.108) with Microsoft SMTP Server id 14.3.352.0; Thu, 9 Aug 2018 06:59:19 -0700 From: Eugen Hristev To: Date: Thu, 9 Aug 2018 16:53:46 +0300 Message-ID: <1533822854-4349-3-git-send-email-eugen.hristev@microchip.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1533822854-4349-1-git-send-email-eugen.hristev@microchip.com> References: <1533822854-4349-1-git-send-email-eugen.hristev@microchip.com> MIME-Version: 1.0 Cc: Maxime Ripard , nicolas.ferre@microchip.com Subject: [U-Boot] [PATCH v2 02/30] w1: Add 1-Wire gpio driver X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.18 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: u-boot-bounces@lists.denx.de Sender: "U-Boot" From: Maxime Ripard Add a bus driver for bitbanging a 1-Wire bus over a GPIO. Signed-off-by: Maxime Ripard [eugen.hristev@microchip.com: addressed review comments] Signed-off-by: Eugen Hristev --- drivers/w1/Kconfig | 7 +++ drivers/w1/Makefile | 2 + drivers/w1/w1-gpio.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 167 insertions(+) create mode 100644 drivers/w1/w1-gpio.c diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig index 64b27c6..d6e0457 100644 --- a/drivers/w1/Kconfig +++ b/drivers/w1/Kconfig @@ -13,6 +13,13 @@ config W1 if W1 +config W1_GPIO + bool "Enable 1-wire GPIO bitbanging" + default no + depends on DM_GPIO + help + Emulate a 1-wire bus using a GPIO. + endif endmenu diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile index f81693b..7fd8697 100644 --- a/drivers/w1/Makefile +++ b/drivers/w1/Makefile @@ -1 +1,3 @@ obj-$(CONFIG_W1) += w1-uclass.o + +obj-$(CONFIG_W1_GPIO) += w1-gpio.o diff --git a/drivers/w1/w1-gpio.c b/drivers/w1/w1-gpio.c new file mode 100644 index 0000000..941ab2c --- /dev/null +++ b/drivers/w1/w1-gpio.c @@ -0,0 +1,158 @@ +/* SPDX-License-Identifier: GPL-2.0+ + * + * Copyright (c) 2015 Free Electrons + * Copyright (c) 2015 NextThing Co + * + * Maxime Ripard + * + */ + +#include +#include +#include + +#include + +#define W1_TIMING_A 6 +#define W1_TIMING_B 64 +#define W1_TIMING_C 60 +#define W1_TIMING_D 10 +#define W1_TIMING_E 9 +#define W1_TIMING_F 55 +#define W1_TIMING_G 0 +#define W1_TIMING_H 480 +#define W1_TIMING_I 70 +#define W1_TIMING_J 410 + +struct w1_gpio_pdata { + struct gpio_desc gpio; + u64 search_id; +}; + +static bool w1_gpio_read_bit(struct udevice *dev) +{ + struct w1_gpio_pdata *pdata = dev_get_platdata(dev); + int val; + + dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT); + udelay(W1_TIMING_A); + + dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_IN); + udelay(W1_TIMING_E); + + val = dm_gpio_get_value(&pdata->gpio); + if (val < 0) + debug("error in retrieving GPIO value"); + udelay(W1_TIMING_F); + + return val; +} + +static u8 w1_gpio_read_byte(struct udevice *dev) +{ + int i; + u8 ret = 0; + + for (i = 0; i < 8; ++i) + ret |= (w1_gpio_read_bit(dev) ? 1 : 0) << i; + + return ret; +} + +static void w1_gpio_write_bit(struct udevice *dev, bool bit) +{ + struct w1_gpio_pdata *pdata = dev_get_platdata(dev); + + dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT); + + bit ? udelay(W1_TIMING_A) : udelay(W1_TIMING_C); + + dm_gpio_set_value(&pdata->gpio, 1); + + bit ? udelay(W1_TIMING_B) : udelay(W1_TIMING_D); +} + +static void w1_gpio_write_byte(struct udevice *dev, u8 byte) +{ + int i; + + for (i = 0; i < 8; ++i) + w1_gpio_write_bit(dev, (byte >> i) & 0x1); +} + +static bool w1_gpio_reset(struct udevice *dev) +{ + struct w1_gpio_pdata *pdata = dev_get_platdata(dev); + int val; + + dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE); + udelay(W1_TIMING_G); + + dm_gpio_set_value(&pdata->gpio, 0); + udelay(W1_TIMING_H); + + dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_IN); + udelay(W1_TIMING_I); + + val = dm_gpio_get_value(&pdata->gpio); + if (val < 0) + debug("error in retrieving GPIO value"); + udelay(W1_TIMING_J); + + return val; +} + +static u8 w1_gpio_triplet(struct udevice *dev, bool bdir) +{ + u8 id_bit = w1_gpio_read_bit(dev); + u8 comp_bit = w1_gpio_read_bit(dev); + u8 retval; + + if (id_bit && comp_bit) + return 0x03; /* error */ + + if (!id_bit && !comp_bit) { + /* Both bits are valid, take the direction given */ + retval = bdir ? 0x04 : 0; + } else { + /* Only one bit is valid, take that direction */ + bdir = id_bit; + retval = id_bit ? 0x05 : 0x02; + } + + w1_gpio_write_bit(dev, bdir); + return retval; +} + +static const struct w1_ops w1_gpio_ops = { + .read_byte = w1_gpio_read_byte, + .reset = w1_gpio_reset, + .triplet = w1_gpio_triplet, + .write_byte = w1_gpio_write_byte, +}; + +static int w1_gpio_ofdata_to_platdata(struct udevice *dev) +{ + struct w1_gpio_pdata *pdata = dev_get_platdata(dev); + int ret; + + ret = gpio_request_by_name(dev, "gpios", 0, &pdata->gpio, 0); + if (ret < 0) + printf("Error claiming GPIO %d\n", ret); + + return ret; +}; + +static const struct udevice_id w1_gpio_id[] = { + { "w1-gpio", 0 }, + { }, +}; + +U_BOOT_DRIVER(w1_gpio_drv) = { + .id = UCLASS_W1, + .name = "w1_gpio_drv", + .of_match = w1_gpio_id, + .ofdata_to_platdata = w1_gpio_ofdata_to_platdata, + .ops = &w1_gpio_ops, + .platdata_auto_alloc_size = sizeof(struct w1_gpio_pdata), +};