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drivers/can/mcp2515.c: Fix the MCP2515 Bit Rate Prescale calculation.

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This commit is contained in:
Alan Carvalho de Assis 2017-10-27 06:11:37 -06:00 committed by Gregory Nutt
parent 07f441eecb
commit b0ce7753aa
1 changed files with 13 additions and 4 deletions
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17
drivers/can/mcp2515.c
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@ -76,11 +76,20 @@
#define MCP2515_TSEG2 MCP2515_PHSEG2
#define MCP2515_BRP ((uint8_t)(((float) MCP2515_CANCLK_FREQUENCY / \
((float)(MCP2515_TSEG1 + MCP2515_TSEG2 + 1) * \
(float)CONFIG_MCP2515_BITRATE)) - 1))
(float)(2 * CONFIG_MCP2515_BITRATE))) - 1))
#define MCP2515_SJW CONFIG_MCP2515_SJW
#if MCP2515_TSEG1 > 16
# error Invalid MCP2515 TSEG1
#if MCP2515_PROPSEG < 1
# error Invalid PROPSEG. It cannot be lower than 1
#endif
#if MCP2515_PROPSEG > 8
# error Invalid PROPSEG. It cannot be greater than 8
#endif
#if MCP2515_PHSEG1 < 1
# error Invalid PHSEG1. It cannot be lower than 1
#endif
#if MCP2515_PHSEG1 > 8
# error Invalid PHSEG1. It cannot be greater than 1
#endif
#if MCP2515_TSEG2 < 2
# error Invalid TSEG2. It cannot be lower than 2
@ -1404,7 +1413,7 @@ static int mcp2515_ioctl(FAR struct can_dev_s *dev, int cmd, unsigned long arg)
mcp2515_readregs(priv, MCP2515_CNF1, &regval, 1);
bt->bt_sjw = ((regval & CNF1_SJW_MASK) >> CNF1_SJW_SHIFT) + 1;
brp = ((regval & CNF1_BRP_MASK) >> CNF1_BRP_SHIFT) + 1;
brp = (((regval & CNF1_BRP_MASK) >> CNF1_BRP_SHIFT) + 1) * 2;
mcp2515_readregs(priv, MCP2515_CNF2, &regval, 1);
bt->bt_tseg1 = ((regval & CNF2_PRSEG_MASK) >> CNF2_PRSEG_SHIFT) + 1;