tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
i2c: tegra: Add de-bounce cycles.
This enables debouncing of the I2C lines. The debounce period is
2 * the debounce register field value, in terms of the I2C block's main
clock. The Tegra TRM indicates that a setting yielding >50nS is
desirable. Hence, a setting of 2 => 4 clocks @ 72MHz => ~55nS.
Signed-off-by: Ken Radtke <kradtke@nvidia.com>
[swarren: Added commit description body,
Fixed 80-column limit, Reverted file permission change]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
+3
-1
+3
-1
drivers/i2c/busses/i2c-tegra.c
+3
-1
drivers/i2c/busses/i2c-tegra.c
···
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#define BYTES_PER_FIFO_WORD 4
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#define I2C_CNFG 0x000
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+
#define I2C_CNFG_DEBOUNCE_CNT_SHIFT 12
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#define I2C_CNFG_PACKET_MODE_EN (1<<10)
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#define I2C_CNFG_NEW_MASTER_FSM (1<<11)
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#define I2C_STATUS 0x01C
···
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if (i2c_dev->is_dvc)
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tegra_dvc_init(i2c_dev);
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-
val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN;
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+
val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN |
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+
(0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT);
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i2c_writel(i2c_dev, val, I2C_CNFG);
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i2c_writel(i2c_dev, 0, I2C_INT_MASK);
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clk_set_rate(i2c_dev->clk, i2c_dev->bus_clk_rate * 8);