On 05/31/2013 03:26 AM, Oleksandr Dmytryshyn wrote:
> If the i2c controller during suspend will generate an interrupt, it
> can lead to 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.
>
> Change-Id: Ie49165990a4e7c67a4ccf2e4a66cd3b78f2e2b70
Remove this.
> Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxx>
> ---
> drivers/i2c/busses/i2c-omap.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> 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 */
--
------------------
Dan Murphy
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