From patchwork Fri Feb 25 07:39:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Tu X-Patchwork-Id: 546123 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BD57C433FE for ; Fri, 25 Feb 2022 07:40:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238194AbiBYHkg (ORCPT ); Fri, 25 Feb 2022 02:40:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232659AbiBYHkd (ORCPT ); Fri, 25 Feb 2022 02:40:33 -0500 Received: from mail-sh.amlogic.com (mail-sh.amlogic.com [58.32.228.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59E3527027A; Thu, 24 Feb 2022 23:40:01 -0800 (PST) Received: from droid06.amlogic.com (10.18.11.248) by mail-sh.amlogic.com (10.18.11.5) with Microsoft SMTP Server id 15.1.2176.14; Fri, 25 Feb 2022 15:39:55 +0800 From: Yu Tu To: , , , CC: Greg Kroah-Hartman , Jiri Slaby , Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Yu Tu Subject: [PATCH V7 3/6] tty: serial: meson: Describes the calculation of the UART baud rate clock using a clock frame Date: Fri, 25 Feb 2022 15:39:19 +0800 Message-ID: <20220225073922.3947-4-yu.tu@amlogic.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220225073922.3947-1-yu.tu@amlogic.com> References: <20220225073922.3947-1-yu.tu@amlogic.com> MIME-Version: 1.0 X-Originating-IP: [10.18.11.248] Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Using the common Clock code to describe the UART baud rate clock makes it easier for the UART driver to be compatible with the baud rate requirements of the UART IP on different meson chips. Signed-off-by: Yu Tu --- drivers/tty/serial/meson_uart.c | 194 +++++++++++++++++++++++--------- 1 file changed, 142 insertions(+), 52 deletions(-) diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c index 7570958d010c..4768d51fac70 100644 --- a/drivers/tty/serial/meson_uart.c +++ b/drivers/tty/serial/meson_uart.c @@ -6,6 +6,7 @@ */ #include +#include #include #include #include @@ -65,9 +66,7 @@ #define AML_UART_RECV_IRQ(c) ((c) & 0xff) /* AML_UART_REG5 bits */ -#define AML_UART_BAUD_MASK 0x7fffff #define AML_UART_BAUD_USE BIT(23) -#define AML_UART_BAUD_XTAL BIT(24) #define AML_UART_PORT_NUM 12 #define AML_UART_PORT_OFFSET 6 @@ -76,6 +75,11 @@ #define AML_UART_POLL_USEC 5 #define AML_UART_TIMEOUT_USEC 10000 +struct meson_uart_data { + struct clk *baud_clk; + bool use_xtal_clk; +}; + static struct uart_driver meson_uart_driver; static struct uart_port *meson_ports[AML_UART_PORT_NUM]; @@ -293,19 +297,17 @@ static int meson_uart_startup(struct uart_port *port) static void meson_uart_change_speed(struct uart_port *port, unsigned long baud) { + struct meson_uart_data *private_data = port->private_data; u32 val; while (!meson_uart_tx_empty(port)) cpu_relax(); - if (port->uartclk == 24000000) { - val = ((port->uartclk / 3) / baud) - 1; - val |= AML_UART_BAUD_XTAL; - } else { - val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1; - } + val = readl(port->membase + AML_UART_REG5); val |= AML_UART_BAUD_USE; writel(val, port->membase + AML_UART_REG5); + + clk_set_rate(private_data->baud_clk, baud); } static void meson_uart_set_termios(struct uart_port *port, @@ -395,11 +397,20 @@ static int meson_uart_verify_port(struct uart_port *port, static void meson_uart_release_port(struct uart_port *port) { - /* nothing to do */ + struct meson_uart_data *private_data = port->private_data; + + clk_disable_unprepare(private_data->baud_clk); } static int meson_uart_request_port(struct uart_port *port) { + struct meson_uart_data *private_data = port->private_data; + int ret; + + ret = clk_prepare_enable(private_data->baud_clk); + if (ret) + return ret; + return 0; } @@ -629,57 +640,106 @@ static struct uart_driver meson_uart_driver = { .cons = MESON_SERIAL_CONSOLE, }; -static inline struct clk *meson_uart_probe_clock(struct device *dev, - const char *id) -{ - struct clk *clk = NULL; - int ret; - - clk = devm_clk_get(dev, id); - if (IS_ERR(clk)) - return clk; - - ret = clk_prepare_enable(clk); - if (ret) { - dev_err(dev, "couldn't enable clk\n"); - return ERR_PTR(ret); - } +static const struct clk_div_table xtal_div_table[] = { + { 0, 3 }, + { 1, 1 }, + { 2, 2 }, + { 3, 2 }, +}; - devm_add_action_or_reset(dev, - (void(*)(void *))clk_disable_unprepare, - clk); +static u32 use_xtal_mux_table; - return clk; -} - -static int meson_uart_probe_clocks(struct platform_device *pdev, - struct uart_port *port) +static int meson_uart_probe_clocks(struct uart_port *port) { - struct clk *clk_xtal = NULL; - struct clk *clk_pclk = NULL; - struct clk *clk_baud = NULL; + struct meson_uart_data *private_data = port->private_data; + struct clk *clk_baud, *clk_xtal; + struct clk_hw *hw, *clk81_div4_hw; + char clk_name[32]; + struct clk_parent_data use_xtal_mux_parents; - clk_pclk = meson_uart_probe_clock(&pdev->dev, "pclk"); - if (IS_ERR(clk_pclk)) - return PTR_ERR(clk_pclk); + clk_baud = devm_clk_get(port->dev, "baud"); + if (IS_ERR(clk_baud)) { + dev_err(port->dev, "Failed to get the 'baud' clock\n"); + return PTR_ERR(clk_baud); + } - clk_xtal = meson_uart_probe_clock(&pdev->dev, "xtal"); + clk_xtal = devm_clk_get(port->dev, "xtal"); if (IS_ERR(clk_xtal)) - return PTR_ERR(clk_xtal); - - clk_baud = meson_uart_probe_clock(&pdev->dev, "baud"); - if (IS_ERR(clk_baud)) - return PTR_ERR(clk_baud); + return dev_err_probe(port->dev, PTR_ERR(clk_xtal), + "Failed to get the 'xtal' clock\n"); + + snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev), + "clk81_div4"); + clk81_div4_hw = devm_clk_hw_register_fixed_factor(port->dev, + clk_name, + __clk_get_name(clk_baud), + CLK_SET_RATE_NO_REPARENT, + 1, 4); + if (IS_ERR(clk81_div4_hw)) + return PTR_ERR(clk81_div4_hw); + + snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev), + "xtal_div"); + hw = devm_clk_hw_register_divider_table(port->dev, + clk_name, + __clk_get_name(clk_baud), + CLK_SET_RATE_NO_REPARENT, + port->membase + AML_UART_REG5, + 26, 2, + CLK_DIVIDER_READ_ONLY, + xtal_div_table, NULL); + if (IS_ERR(hw)) + return PTR_ERR(hw); + + if (private_data->use_xtal_clk) { + use_xtal_mux_table = 1; + use_xtal_mux_parents.hw = hw; + } else { + use_xtal_mux_parents.hw = clk81_div4_hw; + } - port->uartclk = clk_get_rate(clk_baud); + snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev), + "use_xtal"); + hw = __devm_clk_hw_register_mux(port->dev, NULL, + clk_name, + 1, + NULL, NULL, + &use_xtal_mux_parents, + CLK_SET_RATE_PARENT, + port->membase + AML_UART_REG5, + 24, 0x1, + CLK_MUX_READ_ONLY, + &use_xtal_mux_table, NULL); + + if (IS_ERR(hw)) + return PTR_ERR(hw); + + port->uartclk = clk_hw_get_rate(hw); + + snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev), + "baud_div"); + hw = devm_clk_hw_register_divider(port->dev, + clk_name, + clk_hw_get_name(hw), + CLK_SET_RATE_PARENT, + port->membase + AML_UART_REG5, + 0, 23, + CLK_DIVIDER_ROUND_CLOSEST, + NULL); + if (IS_ERR(hw)) + return PTR_ERR(hw); + + private_data->baud_clk = hw->clk; return 0; } static int meson_uart_probe(struct platform_device *pdev) { + struct meson_uart_data *private_data; struct resource *res_mem; struct uart_port *port; + struct clk *pclk; u32 fifosize = 64; /* Default is 64, 128 for EE UART_0 */ int ret = 0; int irq; @@ -705,6 +765,15 @@ static int meson_uart_probe(struct platform_device *pdev) if (!res_mem) return -ENODEV; + pclk = devm_clk_get(&pdev->dev, "pclk"); + if (IS_ERR(pclk)) + return dev_err_probe(&pdev->dev, PTR_ERR(pclk), + "Failed to get the 'pclk' clock\n"); + + ret = clk_prepare_enable(pclk); + if (ret) + return ret; + irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; @@ -724,9 +793,13 @@ static int meson_uart_probe(struct platform_device *pdev) if (IS_ERR(port->membase)) return PTR_ERR(port->membase); - ret = meson_uart_probe_clocks(pdev, port); - if (ret) - return ret; + private_data = devm_kzalloc(&pdev->dev, sizeof(*private_data), + GFP_KERNEL); + if (!private_data) + return -ENOMEM; + + if (device_get_match_data(&pdev->dev)) + private_data->use_xtal_clk = true; port->iotype = UPIO_MEM; port->mapbase = res_mem->start; @@ -740,6 +813,11 @@ static int meson_uart_probe(struct platform_device *pdev) port->x_char = 0; port->ops = &meson_uart_ops; port->fifosize = fifosize; + port->private_data = private_data; + + ret = meson_uart_probe_clocks(port); + if (ret) + return ret; meson_ports[pdev->id] = port; platform_set_drvdata(pdev, port); @@ -766,10 +844,22 @@ static int meson_uart_remove(struct platform_device *pdev) } static const struct of_device_id meson_uart_dt_match[] = { - { .compatible = "amlogic,meson6-uart" }, - { .compatible = "amlogic,meson8-uart" }, - { .compatible = "amlogic,meson8b-uart" }, - { .compatible = "amlogic,meson-gx-uart" }, + { + .compatible = "amlogic,meson6-uart", + .data = (void *)false, + }, + { + .compatible = "amlogic,meson8-uart", + .data = (void *)false, + }, + { + .compatible = "amlogic,meson8b-uart", + .data = (void *)false, + }, + { + .compatible = "amlogic,meson-gx-uart", + .data = (void *)true, + }, { /* sentinel */ }, }; MODULE_DEVICE_TABLE(of, meson_uart_dt_match);