| Message ID | 1370245040-14753-1-git-send-email-oleksandr.dmytryshyn@ti.com |
|---|---|
| State | Accepted |
| Headers | show |
On Mon, Jun 03, 2013 at 10:37:20AM +0300, Oleksandr Dmytryshyn wrote: > We've been lucky not to have any interrupts fire during the suspend > path, otherwise we would have unpredictable behaviour in the kernel. > > Based on the logic of the kernel code interrupts from i2c should be > prohibited during suspend. Kernel writes 0 to the I2C_IE register in > the omap_i2c_runtime_suspend() function. In the other side kernel > writes saved interrupt flags to the I2C_IE register in > omap_i2c_runtime_resume() function. I.e. interrupts should be disabled > during suspend. > > This works for chips with version1 registers scheme. Interrupts are > disabled during suspend. For chips with version2 scheme registers > writting 0 to the I2C_IE register does nothing (because now the > I2C_IRQENABLE_SET register is located at this address). This register > is used to enable interrupts. For disabling interrupts > I2C_IRQENABLE_CLR register should be used. > > Because the registers I2C_IRQENABLE_SET and I2C_IE have the same > addresses, the interrupt enabling procedure is unchanged. > > I've checked that interrupts in the i2c controller are still enabled > after writting 0 to the I2C_IRQENABLE_SET register. With this patch > interrupts are disabled in the omap_i2c_runtime_suspend() function. > > Patch is based on: > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > tag: v3.10-rc2 > > Verified on OMAP4430. > > Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@ti.com> Kevin, I think you are fine with this patch now?
On Mon, Jun 03, 2013 at 10:37:20AM +0300, Oleksandr Dmytryshyn wrote: > We've been lucky not to have any interrupts fire during the suspend > path, otherwise we would have unpredictable behaviour in the kernel. > > Based on the logic of the kernel code interrupts from i2c should be > prohibited during suspend. Kernel writes 0 to the I2C_IE register in > the omap_i2c_runtime_suspend() function. In the other side kernel > writes saved interrupt flags to the I2C_IE register in > omap_i2c_runtime_resume() function. I.e. interrupts should be disabled > during suspend. > > This works for chips with version1 registers scheme. Interrupts are > disabled during suspend. For chips with version2 scheme registers > writting 0 to the I2C_IE register does nothing (because now the > I2C_IRQENABLE_SET register is located at this address). This register > is used to enable interrupts. For disabling interrupts > I2C_IRQENABLE_CLR register should be used. > > Because the registers I2C_IRQENABLE_SET and I2C_IE have the same > addresses, the interrupt enabling procedure is unchanged. > > I've checked that interrupts in the i2c controller are still enabled > after writting 0 to the I2C_IRQENABLE_SET register. With this patch > interrupts are disabled in the omap_i2c_runtime_suspend() function. > > Patch is based on: > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > tag: v3.10-rc2 Last paragraph should be below "---". > > Verified on OMAP4430. > > Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@ti.com> Applied to for-next, thanks!
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index e02f9e3..64c26f9 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -180,6 +180,8 @@ enum { #define I2C_OMAP_ERRATA_I207 (1 << 0) #define I2C_OMAP_ERRATA_I462 (1 << 1) +#define OMAP_I2C_IP_V2_INTERRUPTS_MASK 0x6FFF + struct omap_i2c_dev { spinlock_t lock; /* IRQ synchronization */ struct device *dev; @@ -193,6 +195,7 @@ struct omap_i2c_dev { long latency); u32 speed; /* Speed of bus in kHz */ u32 flags; + u16 scheme; u16 cmd_err; u8 *buf; u8 *regs; @@ -1082,7 +1085,7 @@ omap_i2c_probe(struct platform_device *pdev) int irq; int r; u32 rev; - u16 minor, major, scheme; + u16 minor, major; /* NOTE: driver uses the static register mapping */ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -1159,8 +1162,8 @@ omap_i2c_probe(struct platform_device *pdev) */ rev = __raw_readw(dev->base + 0x04); - scheme = OMAP_I2C_SCHEME(rev); - switch (scheme) { + dev->scheme = OMAP_I2C_SCHEME(rev); + switch (dev->scheme) { case OMAP_I2C_SCHEME_0: dev->regs = (u8 *)reg_map_ip_v1; dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG); @@ -1289,7 +1292,11 @@ static int omap_i2c_runtime_suspend(struct device *dev) _dev->iestate = omap_i2c_read_reg(_dev, OMAP_I2C_IE_REG); - omap_i2c_write_reg(_dev, OMAP_I2C_IE_REG, 0); + if (_dev->scheme == OMAP_I2C_SCHEME_0) + omap_i2c_write_reg(_dev, OMAP_I2C_IE_REG, 0); + else + omap_i2c_write_reg(_dev, OMAP_I2C_IP_V2_IRQENABLE_CLR, + OMAP_I2C_IP_V2_INTERRUPTS_MASK); if (_dev->rev < OMAP_I2C_OMAP1_REV_2) { omap_i2c_read_reg(_dev, OMAP_I2C_IV_REG); /* Read clears */
We've been lucky not to have any interrupts fire during the suspend path, otherwise we would have unpredictable behaviour in the kernel. Based on the logic of the kernel code interrupts from i2c should be prohibited during suspend. Kernel writes 0 to the I2C_IE register in the omap_i2c_runtime_suspend() function. In the other side kernel writes saved interrupt flags to the I2C_IE register in omap_i2c_runtime_resume() function. I.e. interrupts should be disabled during suspend. This works for chips with version1 registers scheme. Interrupts are disabled during suspend. For chips with version2 scheme registers writting 0 to the I2C_IE register does nothing (because now the I2C_IRQENABLE_SET register is located at this address). This register is used to enable interrupts. For disabling interrupts I2C_IRQENABLE_CLR register should be used. Because the registers I2C_IRQENABLE_SET and I2C_IE have the same addresses, the interrupt enabling procedure is unchanged. I've checked that interrupts in the i2c controller are still enabled after writting 0 to the I2C_IRQENABLE_SET register. With this patch interrupts are disabled in the omap_i2c_runtime_suspend() function. Patch is based on: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git tag: v3.10-rc2 Verified on OMAP4430. Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@ti.com> --- drivers/i2c/busses/i2c-omap.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)