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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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45b8ee7182
Some hardware need some time to switch from a bus to another. This can cause the first transfers following the selection of a bus to fail. There is no way to configure this kind of waiting time in the driver. Add support for the 'settle-time-us' device-tree property. When set, the i2c_mux_gpio_select() applies a delay before returning, leaving enough time to the hardware to switch to the new bus. Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com> Reviewed-by: Andi Shyti <andi.shyti@kernel.org> Acked-by: Peter Rosin <peda@axentia.se> Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
34 lines
956 B
C
34 lines
956 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* i2c-mux-gpio interface to platform code
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*
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* Peter Korsgaard <peter.korsgaard@barco.com>
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*/
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#ifndef _LINUX_I2C_MUX_GPIO_H
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#define _LINUX_I2C_MUX_GPIO_H
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/* MUX has no specific idle mode */
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#define I2C_MUX_GPIO_NO_IDLE ((unsigned)-1)
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/**
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* struct i2c_mux_gpio_platform_data - Platform-dependent data for i2c-mux-gpio
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* @parent: Parent I2C bus adapter number
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* @base_nr: Base I2C bus number to number adapters from or zero for dynamic
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* @values: Array of bitmasks of GPIO settings (low/high) for each
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* position
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* @n_values: Number of multiplexer positions (busses to instantiate)
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* @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used
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* @settle_time: Delay to wait when a new bus is selected
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*/
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struct i2c_mux_gpio_platform_data {
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int parent;
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int base_nr;
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const unsigned *values;
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int n_values;
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unsigned idle;
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u32 settle_time;
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};
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#endif /* _LINUX_I2C_MUX_GPIO_H */
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