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i2c: designware: Call i2c_dw_clk_rate() only when calculating timings

PATCH Applied Jarkko Nikula 3 participants 3 messages Oct 1, 2018 – Oct 5, 2018

Subsystems (4)
Stable branch I2C subsystem host drivers Intel LPSS (Low Power SubSystem) drivers Synopsys DesignWare I2C driver
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Jarkko Nikula

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#0 lore raw

PATCH 1/1 i2c: designware: Call i2c_dw_clk_rate() only when calculating timings

There are platforms which don't provide input clock rate but provide I2C timing parameters. Commit 3bd4f277274b ("i2c: designware: Call i2c_dw_clk_rate() only once in i2c_dw_init_master()") causes needless warning during probe on those platforms since i2c_dw_clk_rate(), which causes the warning when input clock is unknown, is called even when there is no need to calculate timing parameters.

Fixes 3bd4f277274b ("i2c: designware: Call i2c_dw_clk_rate() only once in i2c_dw_init_master()")
Reported-by Ard Biesheuvel <[email protected]>
Cc <[email protected]> # 4.19
Signed-off-by Jarkko Nikula <[email protected]>

---
for current 4.19-rc6. I Cc'ed stable just in case this doesn't hit the v4.19.

---
 drivers/i2c/busses/i2c-designware-master.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
drivers/i2c/busses/i2c-designware-master.c +3 -1
index 94d94b4a9a0d..18cc324f3ca9 100644
@@ -34,11 +34,11 @@ static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
 
 static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 {
-	u32 ic_clk = i2c_dw_clk_rate(dev);
 	const char *mode_str, *fp_str = "";
 	u32 comp_param1;
 	u32 sda_falling_time, scl_falling_time;
 	struct i2c_timings *t = &dev->timings;
+	u32 ic_clk;
 	int ret;
 
 	ret = i2c_dw_acquire_lock(dev);

@@ -53,6 +53,7 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 
 	/* Calculate SCL timing parameters for standard mode if not set */
 	if (!dev->ss_hcnt || !dev->ss_lcnt) {
+		ic_clk = i2c_dw_clk_rate(dev);
 		dev->ss_hcnt =
 			i2c_dw_scl_hcnt(ic_clk,
 					4000,	/* tHD;STA = tHIGH = 4.0 us */

@@ -89,6 +90,7 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 	 * needed also in high speed mode.
 	 */
 	if (!dev->fs_hcnt || !dev->fs_lcnt) {
+		ic_clk = i2c_dw_clk_rate(dev);
 		dev->fs_hcnt =
 			i2c_dw_scl_hcnt(ic_clk,
 					600,	/* tHD;STA = tHIGH = 0.6 us */
Signature · 1 line
2.19.0
Tested-by on v1 1/1
#1 lore raw
Quoted 11 lines · Jarkko Nikula

There are platforms which don't provide input clock rate but provide I2C timing parameters. Commit 3bd4f277274b ("i2c: designware: Call i2c_dw_clk_rate() only once in i2c_dw_init_master()") causes needless warning during probe on those platforms since i2c_dw_clk_rate(), which causes the warning when input clock is unknown, is called even when there is no need to calculate timing parameters.

Fixes 3bd4f277274b ("i2c: designware: Call i2c_dw_clk_rate() only once in i2c_dw_init_master()")
Reported-by Ard Biesheuvel <[email protected]>
Cc <[email protected]> # 4.19
Signed-off-by Jarkko Nikula <[email protected]>
Tested-by Ard Biesheuvel <[email protected]>

Thanks!

Quoted 43 lines

---
for current 4.19-rc6. I Cc'ed stable just in case this doesn't hit the v4.19.

---
 drivers/i2c/busses/i2c-designware-master.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
drivers/i2c/busses/i2c-designware-master.c +3 -2
index 94d94b4a9a0d..18cc324f3ca9 100644
@@ -34,11 +34,11 @@ static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
 
 static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 {
-       u32 ic_clk = i2c_dw_clk_rate(dev);
        const char *mode_str, *fp_str = "";
        u32 comp_param1;
        u32 sda_falling_time, scl_falling_time;
        struct i2c_timings *t = &dev->timings;
+       u32 ic_clk;
        int ret;
 
        ret = i2c_dw_acquire_lock(dev);

@@ -53,6 +53,7 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 
        /* Calculate SCL timing parameters for standard mode if not set */
        if (!dev->ss_hcnt || !dev->ss_lcnt) {
+               ic_clk = i2c_dw_clk_rate(dev);
                dev->ss_hcnt =
                        i2c_dw_scl_hcnt(ic_clk,
                                        4000,   /* tHD;STA = tHIGH = 4.0 us */

@@ -89,6 +90,7 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
         * needed also in high speed mode.
         */
        if (!dev->fs_hcnt || !dev->fs_lcnt) {
+               ic_clk = i2c_dw_clk_rate(dev);
                dev->fs_hcnt =
                        i2c_dw_scl_hcnt(ic_clk,
                                        600,    /* tHD;STA = tHIGH = 0.6 us */
--

2.19.0

Applied
#2 lore raw
In reply to Jarkko Nikula
Quoted 11 lines · Jarkko Nikula

There are platforms which don't provide input clock rate but provide I2C timing parameters. Commit 3bd4f277274b ("i2c: designware: Call i2c_dw_clk_rate() only once in i2c_dw_init_master()") causes needless warning during probe on those platforms since i2c_dw_clk_rate(), which causes the warning when input clock is unknown, is called even when there is no need to calculate timing parameters.

Fixes 3bd4f277274b ("i2c: designware: Call i2c_dw_clk_rate() only once in i2c_dw_init_master()")
Reported-by Ard Biesheuvel <[email protected]>
Cc <[email protected]> # 4.19
Signed-off-by Jarkko Nikula <[email protected]>

Applied to for-current, thanks!