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011f2c26f1
As usual these patches were extracted and rebased from the raspberry pi repo: https://github.com/raspberrypi/linux/tree/rpi-4.4.y Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
108 lines
3.3 KiB
Diff
108 lines
3.3 KiB
Diff
From eca01622bfb78a9fd65266d0c31a87d5930416bd Mon Sep 17 00:00:00 2001
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From: Devon Fyson <devonfyson@gmail.com>
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Date: Wed, 30 Dec 2015 16:40:47 -0500
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Subject: [PATCH] Extend clock timeout, fix modprobe baudrate parameter.
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Set the BSC_CLKT clock streching timeout to 35ms as per SMBus specs.\n- Increase priority of baudrate parameter passed to modprobe (in /etc/modprobe.d/*.conf or command line). Currently custom baudrates don't work because they are overridden by clock-frequency in the platform_device passed to the function.
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---
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drivers/i2c/busses/i2c-bcm2708.c | 45 ++++++++++++++++++++++++++--------------
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1 file changed, 29 insertions(+), 16 deletions(-)
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--- a/drivers/i2c/busses/i2c-bcm2708.c
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+++ b/drivers/i2c/busses/i2c-bcm2708.c
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@@ -71,7 +71,8 @@
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#define DRV_NAME "bcm2708_i2c"
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-static unsigned int baudrate = CONFIG_I2C_BCM2708_BAUDRATE;
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+static unsigned int baudrate_default = CONFIG_I2C_BCM2708_BAUDRATE;
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+static unsigned int baudrate;
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module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
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MODULE_PARM_DESC(baudrate, "The I2C baudrate");
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@@ -87,6 +88,7 @@ struct bcm2708_i2c {
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int irq;
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struct clk *clk;
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u32 cdiv;
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+ u32 clk_tout;
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struct completion done;
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@@ -126,7 +128,7 @@ static inline void bcm2708_bsc_fifo_fill
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static inline int bcm2708_bsc_setup(struct bcm2708_i2c *bi)
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{
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- u32 cdiv, s;
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+ u32 cdiv, s, clk_tout;
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u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
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int wait_loops = I2C_WAIT_LOOP_COUNT;
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@@ -134,12 +136,14 @@ static inline int bcm2708_bsc_setup(stru
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* Use the value that we cached in the probe.
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*/
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cdiv = bi->cdiv;
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+ clk_tout = bi->clk_tout;
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if (bi->msg->flags & I2C_M_RD)
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c |= BSC_C_INTR | BSC_C_READ;
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else
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c |= BSC_C_INTT;
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+ bcm2708_wr(bi, BSC_CLKT, clk_tout);
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bcm2708_wr(bi, BSC_DIV, cdiv);
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bcm2708_wr(bi, BSC_A, bi->msg->addr);
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bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
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@@ -312,21 +316,24 @@ static int bcm2708_i2c_probe(struct plat
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struct bcm2708_i2c *bi;
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struct i2c_adapter *adap;
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unsigned long bus_hz;
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- u32 cdiv;
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-
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- if (pdev->dev.of_node) {
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- u32 bus_clk_rate;
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- pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
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- if (pdev->id < 0) {
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- dev_err(&pdev->dev, "alias is missing\n");
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- return -EINVAL;
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+ u32 cdiv, clk_tout;
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+
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+ if (!baudrate) {
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+ baudrate = baudrate_default;
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+ if (pdev->dev.of_node) {
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+ u32 bus_clk_rate;
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+ pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
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+ if (pdev->id < 0) {
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+ dev_err(&pdev->dev, "alias is missing\n");
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+ return -EINVAL;
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+ }
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+ if (!of_property_read_u32(pdev->dev.of_node,
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+ "clock-frequency", &bus_clk_rate))
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+ baudrate = bus_clk_rate;
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+ else
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+ dev_warn(&pdev->dev,
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+ "Could not read clock-frequency property\n");
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}
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- if (!of_property_read_u32(pdev->dev.of_node,
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- "clock-frequency", &bus_clk_rate))
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- baudrate = bus_clk_rate;
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- else
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- dev_warn(&pdev->dev,
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- "Could not read clock-frequency property\n");
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}
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regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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@@ -417,7 +424,13 @@ static int bcm2708_i2c_probe(struct plat
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cdiv = 0xffff;
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baudrate = bus_hz / cdiv;
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}
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+
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+ clk_tout = 35/1000*baudrate; //35ms timeout as per SMBus specs.
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+ if (clk_tout > 0xffff)
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+ clk_tout = 0xffff;
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+
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bi->cdiv = cdiv;
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+ bi->clk_tout = clk_tout;
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dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
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pdev->id, (unsigned long)regs->start, irq, baudrate);
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