From patchwork Sun Jun 7 16:23:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manivannan Sadhasivam X-Patchwork-Id: 11591753 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CDCA092A for ; Sun, 7 Jun 2020 16:24:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE56020748 for ; Sun, 7 Jun 2020 16:24:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591547064; bh=VwTciOsPdwIznP882bNkgfO9ZutZE/C70sq9o+aR3Os=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=y3oOA9spY8UCw8JfvSaPnAAK4IFUQbpJYg7orsxeEKkl9x3dL5S9yjW2SU+JBr9IV V5MdP68+XrDhgzNhweEideEE0FAccVHY0o12kixFt5nnfUXgLmb6+BgFFSEsNpAkfK SPYZ36smXQELSTcG3sgbZk3MwIvT+tnhkNnHnZPg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726897AbgFGQYT (ORCPT ); Sun, 7 Jun 2020 12:24:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:49672 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726571AbgFGQYS (ORCPT ); Sun, 7 Jun 2020 12:24:18 -0400 Received: from localhost.localdomain (unknown [157.51.228.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7DFBC2073B; Sun, 7 Jun 2020 16:24:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591547057; bh=VwTciOsPdwIznP882bNkgfO9ZutZE/C70sq9o+aR3Os=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w6kcexPMNJ1A58fGblJMwqTr0e+m7nSP6m42prtENfvNNuhAzn2IArGNx80Jq9JM+ +yhPqflQeowkOroGMQ9mrzlUMyqDj1beRjql/mnHwU+JGruMIwhhOLt8u2vqr59Vlz TTqrLy7ioAX0VxmJkBeHIpg/AOwdKmj36U7B4k4g= From: Manivannan Sadhasivam To: johan@kernel.org, gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, patong.mxl@gmail.com, linus.walleij@linaro.org, mchehab+huawei@kernel.org, Manivannan Sadhasivam , linux-gpio@vger.kernel.org Subject: [RESEND PATCH v4 2/3] usb: serial: xr_serial: Add gpiochip support Date: Sun, 7 Jun 2020 21:53:49 +0530 Message-Id: <20200607162350.21297-3-mani@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200607162350.21297-1-mani@kernel.org> References: <20200607162350.21297-1-mani@kernel.org> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Add gpiochip support for Maxlinear/Exar USB to serial converter for controlling the available gpios. Inspired from cp210x usb to serial converter driver. Cc: Linus Walleij Cc: linux-gpio@vger.kernel.org Reviewed-by: Linus Walleij Signed-off-by: Manivannan Sadhasivam --- drivers/usb/serial/xr_serial.c | 209 ++++++++++++++++++++++++++++++++- 1 file changed, 208 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c index bb7df79cc129..2240fbc9ea7f 100644 --- a/drivers/usb/serial/xr_serial.c +++ b/drivers/usb/serial/xr_serial.c @@ -10,6 +10,7 @@ * Copyright (c) 2020 Manivannan Sadhasivam */ +#include #include #include #include @@ -17,6 +18,18 @@ #include #include +#ifdef CONFIG_GPIOLIB +enum gpio_pins { + GPIO_RI = 0, + GPIO_CD, + GPIO_DSR, + GPIO_DTR, + GPIO_CTS, + GPIO_RTS, + GPIO_MAX, +}; +#endif + static void xr_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios); @@ -39,6 +52,11 @@ struct xr_uart_regs { }; struct xr_port_private { +#ifdef CONFIG_GPIOLIB + struct gpio_chip gc; + bool gpio_registered; + enum gpio_pins pin_status[GPIO_MAX]; +#endif const struct xr_uart_regs *regs; bool port_open; }; @@ -390,6 +408,13 @@ static void xr_set_flow_mode(struct tty_struct *tty, */ gpio_mode &= ~UART_MODE_GPIO_MASK; if (cflag & CRTSCTS) { +#ifdef CONFIG_GPIOLIB + /* Check if the CTS/RTS pins are occupied */ + if (port_priv->pin_status[GPIO_RTS] || + port_priv->pin_status[GPIO_CTS]) + return; +#endif + dev_dbg(&port->dev, "Enabling hardware flow ctrl\n"); flow = UART_FLOW_MODE_HW; gpio_mode |= UART_MODE_RTS_CTS; @@ -497,6 +522,17 @@ static int xr_tiocmset_port(struct usb_serial_port *port, u8 gpio_set = 0; u8 gpio_clr = 0; +#ifdef CONFIG_GPIOLIB + /* Check if the RTS/DTR pins are occupied */ + if (set & TIOCM_RTS || clear & TIOCM_RTS) + if (port_priv->pin_status[GPIO_RTS]) + return -EBUSY; + + if (set & TIOCM_DTR || clear & TIOCM_DTR) + if (port_priv->pin_status[GPIO_DTR]) + return -EBUSY; +#endif + /* Modem control pins are active low, so set & clr are swapped */ if (set & TIOCM_RTS) gpio_clr |= UART_MODE_RTS; @@ -589,9 +625,175 @@ static void xr_break_ctl(struct tty_struct *tty, int break_state) state); } +#ifdef CONFIG_GPIOLIB + +static int xr_gpio_request(struct gpio_chip *gc, unsigned int offset) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + + /* + * Do not proceed if the port is open. This is done to avoid changing + * the GPIO configuration used by the serial driver. + */ + if (port_priv->port_open) + return -EBUSY; + + /* Mark the GPIO pin as busy */ + port_priv->pin_status[offset] = true; + + return 0; +} + +static void xr_gpio_free(struct gpio_chip *gc, unsigned int offset) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + + /* Mark the GPIO pin as free */ + port_priv->pin_status[offset] = false; +} + +static int xr_gpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + int ret; + u8 gpio_status; + + ret = xr_get_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_status, &gpio_status); + if (ret) + return ret; + + return !!(gpio_status & BIT(gpio)); +} + +static void xr_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + + if (val) + xr_set_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_set, BIT(gpio)); + else + xr_set_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_clr, BIT(gpio)); +} + +static int xr_gpio_direction_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + int ret; + u8 gpio_dir; + + ret = xr_get_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_dir, &gpio_dir); + if (ret) + return ret; + + /* Logic 0 = input and Logic 1 = output */ + return !(gpio_dir & BIT(gpio)); +} + +static int xr_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + int ret; + u8 gpio_dir; + + ret = xr_get_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_dir, &gpio_dir); + if (ret) + return ret; + + gpio_dir &= ~BIT(gpio); + + return xr_set_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_dir, gpio_dir); +} + +static int xr_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio, + int val) +{ + struct usb_serial_port *port = gpiochip_get_data(gc); + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + int ret; + u8 gpio_dir; + + xr_gpio_set(gc, gpio, val); + + ret = xr_get_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_dir, &gpio_dir); + if (ret) + return ret; + + gpio_dir |= BIT(gpio); + + ret = xr_set_reg(port, XR21V141X_UART_REG_BLOCK, + port_priv->regs->gpio_dir, gpio_dir); + if (ret) + return ret; + + return 0; +} + +static int xr_gpio_init(struct usb_serial_port *port) +{ + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + int ret = 0; + + port_priv->gc.ngpio = 6; + port_priv->gc.label = "xr_gpios"; + port_priv->gc.request = xr_gpio_request; + port_priv->gc.free = xr_gpio_free; + port_priv->gc.get_direction = xr_gpio_direction_get; + port_priv->gc.direction_input = xr_gpio_direction_input; + port_priv->gc.direction_output = xr_gpio_direction_output; + port_priv->gc.get = xr_gpio_get; + port_priv->gc.set = xr_gpio_set; + port_priv->gc.owner = THIS_MODULE; + port_priv->gc.parent = &port->dev; + port_priv->gc.base = -1; + port_priv->gc.can_sleep = true; + + ret = gpiochip_add_data(&port_priv->gc, port); + if (!ret) + port_priv->gpio_registered = true; + + return ret; +} + +static void xr_gpio_remove(struct usb_serial_port *port) +{ + struct xr_port_private *port_priv = usb_get_serial_port_data(port); + + if (port_priv->gpio_registered) { + gpiochip_remove(&port_priv->gc); + port_priv->gpio_registered = false; + } +} + +#else + +static int xr_gpio_init(struct usb_serial_port *port) +{ + return 0; +} + +static void xr_gpio_remove(struct usb_serial_port *port) +{ +} + +#endif + static int xr_port_probe(struct usb_serial_port *port) { struct xr_port_private *port_priv; + int ret; port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL); if (!port_priv) @@ -602,13 +804,18 @@ static int xr_port_probe(struct usb_serial_port *port) usb_set_serial_port_data(port, port_priv); - return 0; + ret = xr_gpio_init(port); + if (ret) + kfree(port_priv); + + return ret; } static int xr_port_remove(struct usb_serial_port *port) { struct xr_port_private *port_priv = usb_get_serial_port_data(port); + xr_gpio_remove(port); kfree(port_priv); return 0;