https://github.com/torvalds/linux
Revision 12701ce524bc9b7c6345a2425208501fd2c62aad authored by Badhri Jagan Sridharan on 10 May 2021, 21:17:56 UTC, committed by Greg Kroah-Hartman on 13 May 2021, 13:01:04 UTC
This is a regression introduced by 1373fefc6243 ("usb: typec: tcpm: Allow slow charging loops to comply to pSnkStby") When Source advertises Rp-default, tcpm would request 500mA when in SINK_DISCOVERY, Type-C spec advises the sink to follow BC1.2 current limits when Rp-default is advertised. [12750.503381] Requesting mux state 1, usb-role 2, orientation 1 [12750.503837] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS] [12751.003891] state change SNK_STARTUP -> SNK_DISCOVERY [12751.003900] Setting voltage/current limit 5000 mV 500 mA This patch restores the behavior where the tcpm would request 0mA when Rp-default is advertised by the source. [ 73.174252] Requesting mux state 1, usb-role 2, orientation 1 [ 73.174749] state change SNK_ATTACHED -> SNK_STARTUP [rev3 NONE_AMS] [ 73.674800] state change SNK_STARTUP -> SNK_DISCOVERY [ 73.674808] Setting voltage/current limit 5000 mV 0 mA During SNK_DISCOVERY, Cap the current limit to PD_P_SNK_STDBY_MW / 5 only for slow_charger_loop case. Fixes: 1373fefc6243 ("usb: typec: tcpm: Allow slow charging loops to comply to pSnkStby") Reviewed-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com> Link: https://lore.kernel.org/r/20210510211756.3346954-1-badhri@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 parent 3c12878
Tip revision: 12701ce524bc9b7c6345a2425208501fd2c62aad authored by Badhri Jagan Sridharan on 10 May 2021, 21:17:56 UTC
usb: typec: tcpm: Fix SINK_DISCOVERY current limit for Rp-default
usb: typec: tcpm: Fix SINK_DISCOVERY current limit for Rp-default
Tip revision: 12701ce
crc4.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* crc4.c - simple crc-4 calculations.
*/
#include <linux/crc4.h>
#include <linux/module.h>
static const uint8_t crc4_tab[] = {
0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2,
0x1, 0x6, 0xf, 0x8, 0xa, 0xd, 0x4, 0x3,
};
/**
* crc4 - calculate the 4-bit crc of a value.
* @c: starting crc4
* @x: value to checksum
* @bits: number of bits in @x to checksum
*
* Returns the crc4 value of @x, using polynomial 0b10111.
*
* The @x value is treated as left-aligned, and bits above @bits are ignored
* in the crc calculations.
*/
uint8_t crc4(uint8_t c, uint64_t x, int bits)
{
int i;
/* mask off anything above the top bit */
x &= (1ull << bits) - 1;
/* Align to 4-bits */
bits = (bits + 3) & ~0x3;
/* Calculate crc4 over four-bit nibbles, starting at the MSbit */
for (i = bits - 4; i >= 0; i -= 4)
c = crc4_tab[c ^ ((x >> i) & 0xf)];
return c;
}
EXPORT_SYMBOL_GPL(crc4);
MODULE_DESCRIPTION("CRC4 calculations");
MODULE_LICENSE("GPL");
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