kernel/drivers/tty/serial/sprd_serial.c, branch master

serial: sprd: Return -EPROBE_DEFER when uart clock is not ready

2025-11-26T12:12:19Z

In sprd_clk_init(), when devm_clk_get() returns -EPROBE_DEFER for either uart or source clock, we should propagate the error instead of just warning and continuing with NULL clocks. Currently the driver only emits a warning when clock acquisition fails and proceeds with NULL clock pointers. This can lead to issues later when the clocks are actually needed. More importantly, when the clock provider is not ready yet and returns -EPROBE_DEFER, we should return this error to allow deferred probing. This change adds explicit checks for -EPROBE_DEFER after both: 1. devm_clk_get(uport->dev, uart) 2. devm_clk_get(uport->dev, source) When -EPROBE_DEFER is encountered, the function now returns -EPROBE_DEFER to let the driver framework retry probing later when the clock dependencies are resolved. Signed-off-by: Wenhua Lin Link: https://patch.msgid.link/20251022030840.956589-1-Wenhua.Lin@unisoc.com Reviewed-by: Cixi Geng Signed-off-by: Greg Kroah-Hartman

serial: sprd: Add support for sc9632

2024-11-13T14:14:17Z

Due to the platform's new project uart ip upgrade, the new project's timeout interrupt needs to use bit17 while other projects' timeout interrupt needs to use bit13, using private data to adapt and be compatible with all projects. Signed-off-by: Wenhua Lin Link: https://lore.kernel.org/r/20241113110516.2166328-2-Wenhua.Lin@unisoc.com Signed-off-by: Greg Kroah-Hartman

serial: Switch back to struct platform_driver::remove()

2024-10-11T06:13:28Z

After commit 0edb555a65d1 ("platform: Make platform_driver::remove() return void") .remove() is (again) the right callback to implement for platform drivers. Convert all platform drivers below drivers/tty/serial to use .remove(), with the eventual goal to drop struct platform_driver::remove_new(). As .remove() and .remove_new() have the same prototypes, conversion is done by just changing the structure member name in the driver initializer. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20241007205803.444994-7-u.kleine-koenig@baylibre.com Signed-off-by: Greg Kroah-Hartman

tty: serial: switch from circ_buf to kfifo

2024-04-09T13:28:03Z

Switch from struct circ_buf to proper kfifo. kfifo provides much better API, esp. when wrap-around of the buffer needs to be taken into account. Look at pl011_dma_tx_refill() or cpm_uart_tx_pump() changes for example. Kfifo API can also fill in scatter-gather DMA structures, so it easier for that use case too. Look at lpuart_dma_tx() for example. Note that not all drivers can be converted to that (like atmel_serial), they handle DMA specially. Note that usb-serial uses kfifo for TX for ages. omap needed a bit more care as it needs to put a char into FIFO to start the DMA transfer when OMAP_DMA_TX_KICK is set. In that case, we have to do kfifo_dma_out_prepare twice: once to find out the tx_size (to find out if it is worths to do DMA at all -- size >= 4), the second time for the actual transfer. All traces of circ_buf are removed from serial_core.h (and its struct uart_state). Signed-off-by: Jiri Slaby (SUSE) Cc: Al Cooper Cc: Matthias Brugger Cc: AngeloGioacchino Del Regno Cc: Kumaravel Thiagarajan Cc: Tharun Kumar P Cc: Russell King Cc: Vineet Gupta Cc: Richard Genoud Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: Alexander Shiyan Cc: Baruch Siach Cc: Maciej W. Rozycki Cc: Shawn Guo Cc: Sascha Hauer Cc: Fabio Estevam Cc: Neil Armstrong Cc: Kevin Hilman Cc: Jerome Brunet Cc: Martin Blumenstingl Cc: Taichi Sugaya Cc: Takao Orito Cc: Bjorn Andersson Cc: Konrad Dybcio Cc: Pali Rohár Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Aneesh Kumar K.V Cc: Naveen N. Rao Cc: Manivannan Sadhasivam Cc: Krzysztof Kozlowski Cc: Alim Akhtar Cc: Laxman Dewangan Cc: Thierry Reding Cc: Jonathan Hunter Cc: Orson Zhai Cc: Baolin Wang Cc: Chunyan Zhang Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: David S. Miller Cc: Hammer Hsieh Cc: Peter Korsgaard Cc: Timur Tabi Cc: Michal Simek Cc: Sumit Semwal Cc: Christian König Link: https://lore.kernel.org/r/20240405060826.2521-13-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

serial: sprd: Convert to platform remove callback returning void

2023-11-23T19:12:34Z

The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is ignored (apart from emitting a warning) and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new(), which already returns void. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Acked-by: Chunyan Zhang Link: https://lore.kernel.org/r/20231110152927.70601-41-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

serial: sprd: Use port lock wrappers

2023-09-18T09:18:15Z

When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-63-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman

serial: sprd: Fix DMA buffer leak issue

2023-07-30T11:53:55Z

Release DMA buffer when _probe() returns failure to avoid memory leak. Fixes: f4487db58eb7 ("serial: sprd: Add DMA mode support") Signed-off-by: Chunyan Zhang Reviewed-by: Baolin Wang Link: https://lore.kernel.org/r/20230725064053.235448-2-chunyan.zhang@unisoc.com Signed-off-by: Greg Kroah-Hartman

serial: sprd: Assign sprd_port after initialized to avoid wrong access

2023-07-30T11:53:55Z

The global pointer 'sprd_port' may not zero when sprd_probe returns failure, that is a risk for sprd_port to be accessed afterward, and may lead to unexpected errors. For example: There are two UART ports, UART1 is used for console and configured in kernel command line, i.e. "console="; The UART1 probe failed and the memory allocated to sprd_port[1] was released, but sprd_port[1] was not set to NULL; In UART2 probe, the same virtual address was allocated to sprd_port[2], and UART2 probe process finally will go into sprd_console_setup() to register UART1 as console since it is configured as preferred console (filled to console_cmdline[]), but the console parameters (sprd_port[1]) belong to UART2. So move the sprd_port[] assignment to where the port already initialized can avoid the above issue. Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support") Signed-off-by: Chunyan Zhang Link: https://lore.kernel.org/r/20230725064053.235448-1-chunyan.zhang@unisoc.com Signed-off-by: Greg Kroah-Hartman

serial: sprd: Use devm_platform_get_and_ioremap_resource()

2023-07-25T18:26:07Z

Convert platform_get_resource(), devm_ioremap_resource() to a single call to devm_platform_get_and_ioremap_resource(), as this is exactly what this function does. Signed-off-by: Yangtao Li Link: https://lore.kernel.org/r/20230712062853.11007-10-frank.li@vivo.com Signed-off-by: Greg Kroah-Hartman

serial: drivers: switch ch and flag to u8

2023-07-25T17:21:04Z

Now that the serial layer explicitly expects 'u8' for flags and characters, propagate this type to drivers' (RX) routines. Note that amba-pl011's, clps711x's and st-asc's 'ch' are left unchanged because 'ch' contains not only a character, but whole status. Signed-off-by: Jiri Slaby (SUSE) Cc: Tobias Klauser Cc: Russell King Cc: Vineet Gupta Cc: Richard Genoud Cc: Nicolas Ferre Cc: Alexandre Belloni Cc: Claudiu Beznea Cc: Alexander Shiyan Cc: Baruch Siach Cc: "Maciej W. Rozycki" Cc: Taichi Sugaya Cc: Takao Orito Cc: Shawn Guo Cc: Sascha Hauer Cc: Pengutronix Kernel Team Cc: Fabio Estevam Cc: NXP Linux Team Cc: Kevin Cernekee Cc: Krzysztof Kozlowski Cc: Alim Akhtar Cc: Laxman Dewangan Cc: Thierry Reding Cc: Jonathan Hunter Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Orson Zhai Cc: Baolin Wang Cc: Chunyan Zhang Cc: Patrice Chotard Cc: Maxime Coquelin Cc: Alexandre Torgue Cc: Hammer Hsieh Acked-by: Richard GENOUD Acked-by: Tobias Klauser Acked-by: Thierry Reding Acked-by: Maciej W. Rozycki Link: https://lore.kernel.org/r/20230712081811.29004-11-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman