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[96.22.11.200]) by smtp.gmail.com with ESMTPSA id 195sm6132729qkf.30.2022.02.07.15.29.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Feb 2022 15:29:34 -0800 (PST) Date: Mon, 7 Feb 2022 18:29:32 -0500 From: Adrien Thierry To: Andy Shevchenko Cc: "linux-serial@vger.kernel.org" , "linux-rpi-kernel@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Jeremy Linton , Greg Kroah-Hartman , Jiri Slaby , Nicolas Saenz Julienne , Florian Fainelli , Ray Jui , Scott Branden , "bcm-kernel-feedback-list@broadcom.com" Subject: Re: [PATCH v2] serial: 8250_bcm2835aux: Add ACPI support Message-ID: References: <20220203213408.441407-1-athierry@redhat.com> MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=athierry@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Sat, Feb 05, 2022 at 01:58:43AM +0200, Andy Shevchenko wrote: > On Thursday, February 3, 2022, Adrien Thierry wrote: > > > 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 > > --- > > V1 -> V2: Refactored code to remove unnecessary conditional paths and > > intermediate variables > > > > drivers/tty/serial/8250/8250_bcm2835aux.c | 87 ++++++++++++++++++----- > > 1 file changed, 69 insertions(+), 18 deletions(-) > > > > diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c > > b/drivers/tty/serial/8250/8250_bcm2835aux.c > > index fd95860cd661..b7cec2a3b5f7 100644 > > --- a/drivers/tty/serial/8250/8250_bcm2835aux.c > > +++ b/drivers/tty/serial/8250/8250_bcm2835aux.c > > @@ -12,6 +12,7 @@ > > * simultaneously to rs485. > > */ > > > > +#include > > > For what purposes? > Can’t you use device_get_match_data()? > > > > > #include > > #include > > #include > > > property.h? > > > > @@ -44,6 +45,10 @@ struct bcm2835aux_data { > > u32 cntl; > > }; > > > > +struct bcm2835_aux_serial_acpi_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)) { > > @@ -82,8 +87,11 @@ static int bcm2835aux_serial_probe(struct > > platform_device *pdev) > > { > > struct uart_8250_port up = { }; > > struct bcm2835aux_data *data; > > + struct bcm2835_aux_serial_acpi_driver_data *acpi_data; > > struct resource *res; > > int ret; > > + resource_size_t offset = 0; > > + unsigned int uartclk; > > > > Keep reversed Xmas tree order? > > > > > > > /* allocate the custom structure */ > > data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); > > @@ -110,8 +118,11 @@ static int bcm2835aux_serial_probe(struct > > platform_device *pdev) > > > > /* get the clock - this also enables the HW */ > > data->clk = 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"); > > + if (IS_ERR(data->clk)) { > > + ret = device_property_read_u32(&pdev->dev, > > "clock-frequency", &uartclk); > > + if (ret) > > + return dev_err_probe(&pdev->dev, ret, "could not > > get clk\n"); > > + } > > > > /* get the interrupt */ > > ret = platform_get_irq(pdev, 0); > > @@ -125,20 +136,47 @@ static int bcm2835aux_serial_probe(struct > > platform_device *pdev) > > dev_err(&pdev->dev, "memory resource not found"); > > return -EINVAL; > > } > > - up.port.mapbase = res->start; > > - up.port.mapsize = resource_size(res); > > - > > - /* Check for a fixed line number */ > > - ret = of_alias_get_id(pdev->dev.of_node, "serial"); > > - if (ret >= 0) > > - up.port.line = ret; > > - > > - /* enable the clock as a last step */ > > - ret = clk_prepare_enable(data->clk); > > - if (ret) { > > - dev_err(&pdev->dev, "unable to enable uart clock - %d\n", > > - ret); > > - return ret; > > + > > + if (has_acpi_companion(&pdev->dev)) { > > + const struct acpi_device_id *match; > > + > > + match = acpi_match_device(pdev->dev.driver->acpi_match_table, > > &pdev->dev); > > + if (!match) > > + return -ENODEV; > > + > > + acpi_data = (struct bcm2835_aux_serial_acpi_driver_data > > *)match->driver_data; > > > acpi_data naming is fragile. Use something with local namespace or without > it completely (bcm_data, data, ddata, etc). > > > > + > > + /* Some UEFI implementations (e.g. tianocore/edk2 for the > > Raspberry Pi) > > + * describe the miniuart with a base address that > > encompasses the auxiliary > > + * 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. > > + */ > > + offset = acpi_data->offset; > > > > > > + } > > + > > + up.port.mapbase = res->start + offset; > > + up.port.mapsize = resource_size(res) - offset; > > + > > + if (dev_of_node(&pdev->dev)) { > > + /* Check for a fixed line number */ > > + ret = of_alias_get_id(pdev->dev.of_node, "serial"); > > + if (ret >= 0) > > + up.port.line = ret; > > + > > + /* enable the clock as a last step */ > > + ret = clk_prepare_enable(data->clk); > > + if (ret) { > > + dev_err(&pdev->dev, "unable to enable uart clock - > > %d\n", > > + ret); > > + return ret; > > + } > > + > > + uartclk = clk_get_rate(data->clk); > > } > > > > /* the HW-clock divider for bcm2835aux is 8, > > @@ -146,7 +184,7 @@ static int bcm2835aux_serial_probe(struct > > platform_device *pdev) > > * so we have to multiply the actual clock by 2 > > * to get identical baudrates. > > */ > > - up.port.uartclk = clk_get_rate(data->clk) * 2; > > + up.port.uartclk = uartclk * 2; > > > > /* register the port */ > > ret = serial8250_register_8250_port(&up); > > @@ -159,7 +197,9 @@ static int bcm2835aux_serial_probe(struct > > platform_device *pdev) > > return 0; > > > > dis_clk: > > - clk_disable_unprepare(data->clk); > > + if (dev_of_node(&pdev->dev)) > > + clk_disable_unprepare(data->clk); > > + > > > Why do you change this? CCF is null-aware. > > > > return ret; > > } > > > > @@ -173,16 +213,27 @@ static int bcm2835aux_serial_remove(struct > > platform_device *pdev) > > return 0; > > } > > > > +static const struct bcm2835_aux_serial_acpi_driver_data > > bcm2835_acpi_data = { > > + .offset = 0x40 > > > > + comma > > > +}; > > + > > static const struct of_device_id bcm2835aux_serial_match[] = { > > { .compatible = "brcm,bcm2835-aux-uart" }, > > { }, > > }; > > MODULE_DEVICE_TABLE(of, bcm2835aux_serial_match); > > > > +static const struct acpi_device_id bcm2835aux_serial_acpi_match[] = { > > + { "BCM2836", (kernel_ulong_t)&bcm2835_acpi_data }, > > + { }, > > > No comma for terminator entry. > > > > +}; > > +MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match); > > + > > static struct platform_driver bcm2835aux_serial_driver = { > > .driver = { > > .name = "bcm2835-aux-uart", > > .of_match_table = bcm2835aux_serial_match, > > + .acpi_match_table = bcm2835aux_serial_acpi_match, > > }, > > .probe = bcm2835aux_serial_probe, > > .remove = bcm2835aux_serial_remove, > > > > base-commit: 1f2cfdd349b7647f438c1e552dc1b983da86d830 > > -- > > 2.34.1 > > > > > > -- > With Best Regards, > Andy Shevchenko Thanks for your feedback! I've submitted a v3 addressing your comments. Adrien