| Message ID | 1417688512-7644-3-git-send-email-lee.jones@linaro.org |
|---|---|
| State | New |
| Headers | show |
Hi Lee, On Thu, 04 Dec 2014, Lee Jones wrote: > ST's Common Clk Framework is now available. This patch ensures the FSM > makes use of it by obtaining and enabling the EMI clock if provided. If > system fails to provide the EMI clock FSM uses its original default > rate. <snip> I'm not sure I understand this patch. Now that common clock framework is available for STI platforms, why would the emi clock ever not be available? If it is to maintain DT compatability then we are already breaking this with the syscfg 'reg' DT changes which are coming up, and this was deemed OK as the platform is WIP. IMO keeping this legacy code which assumes the bootloader / JTAG has enabled and configured the emi clock correctly is not worth it now that CCF is available for the platform. > - /* TODO: Make this dynamic */ > - emi_freq = STFSM_DEFAULT_EMI_FREQ; > + if (!fsm->clk) { > + dev_warn(fsm->dev, > + "No EMI clock available. Using default 100MHz.\n"); > + > + emi_freq = STFSM_DEFAULT_EMI_FREQ; > + } else > + emi_freq = clk_get_rate(fsm->clk); > > /* > * Calculate clk_div - values between 2 and 128 > @@ -2057,6 +2064,15 @@ static int stfsm_probe(struct platform_device *pdev) > return PTR_ERR(fsm->base); > } > > + fsm->clk = devm_clk_get(&pdev->dev, "emi_clk"); > + if (IS_ERR(fsm->clk)) { > + dev_warn(fsm->dev, "Couldn't find EMI clock.\n"); > + fsm->clk = NULL; > + } else if (clk_prepare_enable(fsm->clk)) { > + dev_warn(fsm->dev, "Failed to enable EMI clock.\n"); If a clock has been provided and we fail to enable it, then surely that is game over? As the code currently is it then goes onto assume in stfsm_set_freq() that the rate is STFSM_DEFAULT_EMI_FREQ which can't be true if it can't enable the clock. regards, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Hi Lee, > On Thu, 04 Dec 2014, Lee Jones wrote: > > > ST's Common Clk Framework is now available. This patch ensures the FSM > > makes use of it by obtaining and enabling the EMI clock if provided. If > > system fails to provide the EMI clock FSM uses its original default > > rate. > > <snip> > > I'm not sure I understand this patch. Now that common clock framework > is available for STI platforms, why would the emi clock ever not be available? > > If it is to maintain DT compatability then we are already breaking this with the > syscfg 'reg' DT changes which are coming up, and this was deemed OK as the platform > is WIP. > > IMO keeping this legacy code which assumes the bootloader / JTAG has enabled and configured > the emi clock correctly is not worth it now that CCF is available for the platform. Also this legacy code will definately break when we we stop booting the kernel with "clk_ignore_unused" parameter. regards, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c index 6e4d3bfe..ddb659f 100644 --- a/drivers/mtd/devices/st_spi_fsm.c +++ b/drivers/mtd/devices/st_spi_fsm.c @@ -24,6 +24,7 @@ #include <linux/delay.h> #include <linux/io.h> #include <linux/of.h> +#include <linux/clk.h> #include "serial_flash_cmds.h" @@ -262,6 +263,7 @@ struct stfsm { struct mtd_info mtd; struct mutex lock; struct flash_info *info; + struct clk *clk; uint32_t configuration; uint32_t fifo_dir_delay; @@ -1906,8 +1908,13 @@ static void stfsm_set_freq(struct stfsm *fsm, uint32_t spi_freq) uint32_t emi_freq; uint32_t clk_div; - /* TODO: Make this dynamic */ - emi_freq = STFSM_DEFAULT_EMI_FREQ; + if (!fsm->clk) { + dev_warn(fsm->dev, + "No EMI clock available. Using default 100MHz.\n"); + + emi_freq = STFSM_DEFAULT_EMI_FREQ; + } else + emi_freq = clk_get_rate(fsm->clk); /* * Calculate clk_div - values between 2 and 128 @@ -2057,6 +2064,15 @@ static int stfsm_probe(struct platform_device *pdev) return PTR_ERR(fsm->base); } + fsm->clk = devm_clk_get(&pdev->dev, "emi_clk"); + if (IS_ERR(fsm->clk)) { + dev_warn(fsm->dev, "Couldn't find EMI clock.\n"); + fsm->clk = NULL; + } else if (clk_prepare_enable(fsm->clk)) { + dev_warn(fsm->dev, "Failed to enable EMI clock.\n"); + fsm->clk = NULL; + } + mutex_init(&fsm->lock); ret = stfsm_init(fsm); @@ -2121,6 +2137,30 @@ static int stfsm_remove(struct platform_device *pdev) return mtd_device_unregister(&fsm->mtd); } +#ifdef CONFIG_PM_SLEEP +static int stfsmfsm_suspend(struct device *dev) +{ + struct stfsm *fsm = dev_get_drvdata(dev); + + if (fsm->clk) + clk_disable_unprepare(fsm->clk); + + return 0; +} + +static int stfsmfsm_resume(struct device *dev) +{ + struct stfsm *fsm = dev_get_drvdata(dev); + + if (fsm->clk) + clk_prepare_enable(fsm->clk); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(stfsm_pm_ops, stfsmfsm_suspend, stfsmfsm_resume); + static const struct of_device_id stfsm_match[] = { { .compatible = "st,spi-fsm", }, {}, @@ -2134,6 +2174,7 @@ static struct platform_driver stfsm_driver = { .name = "st-spi-fsm", .owner = THIS_MODULE, .of_match_table = stfsm_match, + .pm = &stfsm_pm_ops, }, }; module_platform_driver(stfsm_driver);
ST's Common Clk Framework is now available. This patch ensures the FSM makes use of it by obtaining and enabling the EMI clock if provided. If system fails to provide the EMI clock FSM uses its original default rate. Signed-off-by: Lee Jones <lee.jones@linaro.org> --- drivers/mtd/devices/st_spi_fsm.c | 45 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 43 insertions(+), 2 deletions(-)