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[96.22.11.200]) by smtp.gmail.com with ESMTPSA id y2sm5906567qke.33.2022.02.07.15.21.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Feb 2022 15:21:55 -0800 (PST) From: Adrien Thierry To: linux-serial@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Adrien Thierry , Jeremy Linton , Greg Kroah-Hartman , Jiri Slaby , Nicolas Saenz Julienne , Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com Subject: [PATCH v3] serial: 8250_bcm2835aux: Add ACPI support Date: Mon, 7 Feb 2022 18:21:29 -0500 Message-Id: <20220207232129.402882-1-athierry@redhat.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add ACPI support to 8250_bcm2835aux driver. This makes it possible to use the miniuart on the Raspberry Pi with the tianocore/edk2 UEFI firmware. Signed-off-by: Adrien Thierry Reviewed-by: Florian Fainelli Tested-by: Jeremy Linton --- V1 -> V2: Refactored code to remove unnecessary conditional paths and intermediate variables V2 -> V3: Cleaned up coding style and addressed review comments drivers/tty/serial/8250/8250_bcm2835aux.c | 52 ++++++++++++++++++++--- 1 file changed, 46 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial= /8250/8250_bcm2835aux.c index fd95860cd661..2a1226a78a0c 100644 --- a/drivers/tty/serial/8250/8250_bcm2835aux.c +++ b/drivers/tty/serial/8250/8250_bcm2835aux.c @@ -17,6 +17,7 @@ #include #include #include +#include =20 #include "8250.h" =20 @@ -44,6 +45,10 @@ struct bcm2835aux_data { u32 cntl; }; =20 +struct bcm2835_aux_serial_driver_data { + resource_size_t offset; +}; + static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up) { if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX)) { @@ -80,9 +85,12 @@ static void bcm2835aux_rs485_stop_tx(struct uart_8250_po= rt *up) =20 static int bcm2835aux_serial_probe(struct platform_device *pdev) { + const struct bcm2835_aux_serial_driver_data *bcm_data; struct uart_8250_port up =3D { }; struct bcm2835aux_data *data; + resource_size_t offset =3D 0; struct resource *res; + unsigned int uartclk; int ret; =20 /* allocate the custom structure */ @@ -109,9 +117,7 @@ static int bcm2835aux_serial_probe(struct platform_devi= ce *pdev) platform_set_drvdata(pdev, data); =20 /* get the clock - this also enables the HW */ - data->clk =3D devm_clk_get(&pdev->dev, NULL); - if (IS_ERR(data->clk)) - return dev_err_probe(&pdev->dev, PTR_ERR(data->clk), "could not get clk\= n"); + data->clk =3D devm_clk_get_optional(&pdev->dev, NULL); =20 /* get the interrupt */ ret =3D platform_get_irq(pdev, 0); @@ -125,8 +131,24 @@ static int bcm2835aux_serial_probe(struct platform_dev= ice *pdev) dev_err(&pdev->dev, "memory resource not found"); return -EINVAL; } - up.port.mapbase =3D res->start; - up.port.mapsize =3D resource_size(res); + + bcm_data =3D device_get_match_data(&pdev->dev); + + /* Some UEFI implementations (e.g. tianocore/edk2 for the Raspberry Pi) + * describe the miniuart with a base address that encompasses the auxilia= ry + * registers shared between the miniuart and spi. + * + * This is due to historical reasons, see discussion here : + * https://edk2.groups.io/g/devel/topic/87501357#84349 + * + * We need to add the offset between the miniuart and auxiliary + * registers to get the real miniuart base address. + */ + if (bcm_data) + offset =3D bcm_data->offset; + + up.port.mapbase =3D res->start + offset; + up.port.mapsize =3D resource_size(res) - offset; =20 /* Check for a fixed line number */ ret =3D of_alias_get_id(pdev->dev.of_node, "serial"); @@ -141,12 +163,19 @@ static int bcm2835aux_serial_probe(struct platform_de= vice *pdev) return ret; } =20 + uartclk =3D clk_get_rate(data->clk); + if (!uartclk) { + ret =3D device_property_read_u32(&pdev->dev, "clock-frequency", &uartclk= ); + if (ret) + return dev_err_probe(&pdev->dev, ret, "could not get clk rate\n"); + } + /* the HW-clock divider for bcm2835aux is 8, * but 8250 expects a divider of 16, * so we have to multiply the actual clock by 2 * to get identical baudrates. */ - up.port.uartclk =3D clk_get_rate(data->clk) * 2; + up.port.uartclk =3D uartclk * 2; =20 /* register the port */ ret =3D serial8250_register_8250_port(&up); @@ -173,16 +202,27 @@ static int bcm2835aux_serial_remove(struct platform_d= evice *pdev) return 0; } =20 +static const struct bcm2835_aux_serial_driver_data bcm2835_acpi_data =3D { + .offset =3D 0x40, +}; + static const struct of_device_id bcm2835aux_serial_match[] =3D { { .compatible =3D "brcm,bcm2835-aux-uart" }, { }, }; MODULE_DEVICE_TABLE(of, bcm2835aux_serial_match); =20 +static const struct acpi_device_id bcm2835aux_serial_acpi_match[] =3D { + { "BCM2836", (kernel_ulong_t)&bcm2835_acpi_data }, + { } +}; +MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match); + static struct platform_driver bcm2835aux_serial_driver =3D { .driver =3D { .name =3D "bcm2835-aux-uart", .of_match_table =3D bcm2835aux_serial_match, + .acpi_match_table =3D bcm2835aux_serial_acpi_match, }, .probe =3D bcm2835aux_serial_probe, .remove =3D bcm2835aux_serial_remove, base-commit: 2ade8eef993c37a2a43e51a9b1f6c25509a2acce --=20 2.34.1