kernel/linux.git/include/linux/i3c/master.h, branch v6.18.21

i3c: master: Add helpers for DMA mapping and bounce buffer handling

2025-09-16T15:06:42+00:00

Some I3C controllers such as MIPI I3C HCI may pad the last DWORD (32-bit) with stale data from the RX FIFO in DMA transfers if the receive length is not DWORD aligned and when the device DMA is IOMMU mapped. In such a case, a properly sized bounce buffer is required in order to avoid possible data corruption. In a review discussion, proposal was to have a common helpers in I3C core for DMA mapping and bounce buffer handling. Drivers may use the helper i3c_master_dma_map_single() to map a buffer for a DMA transfer. It internally allocates a bounce buffer if buffer is not DMA'able or when the driver requires it for a transfer. Helper i3c_master_dma_unmap_single() does the needed cleanups and data copying from the bounce buffer. Signed-off-by: Jarkko Nikula Reviewed-by: Frank Li Link: https://lore.kernel.org/r/20250822105630.2820009-2-jarkko.nikula@linux.intel.com Signed-off-by: Alexandre Belloni

i3c: Add more parameters for controllers to the header

2025-07-30T23:33:20+00:00

Add standard timing value definition from specification. Signed-off-by: Wolfram Sang Tested-by: Tommaso Merciai Reviewed-by: Frank Li Link: https://lore.kernel.org/r/20250724094146.6443-3-wsa+renesas@sang-engineering.com Signed-off-by: Alexandre Belloni

i3c: Standardize defines for specification parameters

2025-07-30T23:33:20+00:00

Align existing defines to follow the consistent pattern: I3C_BUS___. Prepare the codebase for adding new parameters and help avoid duplication. Signed-off-by: Wolfram Sang Tested-by: Tommaso Merciai Reviewed-by: Frank Li Link: https://lore.kernel.org/r/20250724094146.6443-2-wsa+renesas@sang-engineering.com Signed-off-by: Alexandre Belloni

i3c: Remove the const qualifier from i2c_msg pointer in i2c_xfers API

2025-02-20T21:54:28+00:00

The change is necessary to enable the use of the `i2c_get_dma_safe_msg_buf()` API, which requires a non-const `struct i2c_msg *` to operate. The `i2c_get_dma_safe_msg_buf()` function ensures safe handling of I2C messages when using DMA, making it essential for scenarios where DMA transfers are involved. By removing the `const` qualifier, this patch allows drivers to prepare and manage DMA-safe buffers directly. Signed-off-by: Billy Tsai Reviewed-by: Frank Li Reviewed-by: Wolfram Sang Acked-by: Mukesh Kumar Savaliya Link: https://lore.kernel.org/r/20250204091702.4014466-1-billy_tsai@aspeedtech.com Signed-off-by: Alexandre Belloni

i3c: Document I3C_ADDR_SLOT_EXT_STATUS_MASK

2024-11-02T13:30:39+00:00

As the mask is part of the enum, document it. Reported-by: Stephen Rothwell Link: https://lore.kernel.org/r/20241102132841.2446176-1-alexandre.belloni@bootlin.com Signed-off-by: Alexandre Belloni

i3c: master: Extend address status bit to 4 and add I3C_ADDR_SLOT_EXT_DESIRED

2024-10-31T22:51:00+00:00

Extend the address status bit to 4 and introduce the I3C_ADDR_SLOT_EXT_DESIRED macro to indicate that a device prefers a specific address. This is generally set by the 'assigned-address' in the device tree source (dts) file. ┌────┬─────────────┬───┬─────────┬───┐ │S/Sr│ 7'h7E RnW=0 │ACK│ ENTDAA │ T ├────┐ └────┴─────────────┴───┴─────────┴───┘ │ ┌─────────────────────────────────────────┘ │ ┌──┬─────────────┬───┬─────────────────┬────────────────┬───┬─────────┐ └─►│Sr│7'h7E RnW=1 │ACK│48bit UID BCR DCR│Assign 7bit Addr│PAR│ ACK/NACK│ └──┴─────────────┴───┴─────────────────┴────────────────┴───┴─────────┘ Some master controllers (such as HCI) need to prepare the entire above transaction before sending it out to the I3C bus. This means that a 7-bit dynamic address needs to be allocated before knowing the target device's UID information. However, some I3C targets may request specific addresses (called as "init_dyn_addr"), which is typically specified by the DT-'s assigned-address property. Lower addresses having higher IBI priority. If it is available, i3c_bus_get_free_addr() preferably return a free address that is not in the list of desired addresses (called as "init_dyn_addr"). This allows the device with the "init_dyn_addr" to switch to its "init_dyn_addr" when it hot-joins the I3C bus. Otherwise, if the "init_dyn_addr" is already in use by another I3C device, the target device will not be able to switch to its desired address. If the previous step fails, fallback returning one of the remaining unassigned address, regardless of its state in the desired list. Reviewed-by: Miquel Raynal Signed-off-by: Frank Li Link: https://lore.kernel.org/r/20241021-i3c_dts_assign-v8-2-4098b8bde01e@nxp.com Signed-off-by: Alexandre Belloni

i3c: master: Replace hard code 2 with macro I3C_ADDR_SLOT_STATUS_BITS

2024-10-31T22:51:00+00:00

Replace the hardcoded value 2, which indicates 2 bits for I3C address status, with the predefined macro I3C_ADDR_SLOT_STATUS_BITS. Improve maintainability and extensibility of the code. Reviewed-by: Miquel Raynal Signed-off-by: Frank Li Link: https://lore.kernel.org/r/20241021-i3c_dts_assign-v8-1-4098b8bde01e@nxp.com Signed-off-by: Alexandre Belloni

i3c: master: support to adjust first broadcast address speed

2024-09-17T14:46:22+00:00

According to I3C spec 6.2 Timing Specification, the Open Drain High Period of SCL Clock timing for first broadcast address should be adjusted to 200ns at least. I3C device working as i2c device will see the broadcast to close its Spike Filter then change to work at I3C mode. After that I3C open drain SCL high level should be adjusted back. Signed-off-by: Carlos Song Reviewed-by: Miquel Raynal Reviewed-by: Frank Li Link: https://lore.kernel.org/r/20240910051626.4052552-1-carlos.song@nxp.com Signed-off-by: Alexandre Belloni

i3c: master: Enhance i3c_bus_type visibility for device searching & event monitoring

2024-07-26T12:21:30+00:00

Improve the visibility of i3c_bus_type to facilitate searching for i3c devices attached to the i3c bus. Enable other drivers to use bus_register_notifier to monitor i3c bus device events. Signed-off-by: Bhoomik Gupta Link: https://lore.kernel.org/r/20240708053835.3003986-1-bhoomik.gupta@nxp.com Signed-off-by: Alexandre Belloni

i3c: master: fix kernel-doc check warning

2024-01-14T22:00:50+00:00

Fix warning found by 'scripts/kernel-doc -v -none include/linux/i3c/master.h' include/linux/i3c/master.h:457: warning: Function parameter or member 'enable_hotjoin' not described in 'i3c_master_controller_ops' include/linux/i3c/master.h:457: warning: Function parameter or member 'disable_hotjoin' not described in 'i3c_master_controller_ops' include/linux/i3c/master.h:499: warning: Function parameter or member 'hotjoin' not described in 'i3c_master_controller' Signed-off-by: Frank Li Reviewed-by: Miquel Raynal Link: https://lore.kernel.org/r/20240109052548.2128133-1-Frank.Li@nxp.com Signed-off-by: Alexandre Belloni