> -----Original Message-----
> From: Gopinath, Thara
> Sent: Friday, July 02, 2010 3:48 PM
> To: linux-omap@xxxxxxxxxxxxxxx
> Cc: khilman@xxxxxxxxxxxxxxxxxxx; paul@xxxxxxxxx; Cousson, Benoit; Sripathy,
> Vishwanath; Sawant, Anand; Basak, Partha; Gopinath, Thara
> Subject: [RFC 5/7] OMAP: Introduce set_rate and get_rate API in omap device layer
>
> This patch adds omap_device_set_rate and omap_device_get_rate
> API's which can be used to generic device rate scaling.
>
> Signed-off-by: Thara Gopinath <thara@xxxxxx>
> ---
> arch/arm/plat-omap/include/plat/omap_device.h | 2 +
> arch/arm/plat-omap/omap_device.c | 87
> +++++++++++++++++++++++++
> 2 files changed, 89 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-
> omap/include/plat/omap_device.h
> index 3694b62..e0d06bb 100644
> --- a/arch/arm/plat-omap/include/plat/omap_device.h
> +++ b/arch/arm/plat-omap/include/plat/omap_device.h
> @@ -114,6 +114,8 @@ int omap_device_enable_hwmods(struct omap_device *od);
> int omap_device_disable_clocks(struct omap_device *od);
> int omap_device_enable_clocks(struct omap_device *od);
>
> +int omap_device_set_rate(struct device *dev, unsigned long rate);
> +unsigned long omap_device_get_rate(struct device *dev);
>
> /*
> * Entries should be kept in latency order ascending
> diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
> index 6614cba..900bb5d 100644
> --- a/arch/arm/plat-omap/omap_device.c
> +++ b/arch/arm/plat-omap/omap_device.c
> @@ -85,6 +85,8 @@
>
> #include <plat/omap_device.h>
> #include <plat/omap_hwmod.h>
> +#include <plat/opp.h>
> +#include <plat/voltage.h>
>
> /* These parameters are passed to _omap_device_{de,}activate() */
> #define USE_WAKEUP_LAT 0
> @@ -734,3 +736,88 @@ int omap_device_enable_clocks(struct omap_device *od)
> /* XXX pass along return value here? */
> return 0;
> }
> +
> +/**
> + * omap_device_set_rate - Set a new rate at which the device is to operate
> + * @dev : the device pointer
> + * @rate : the rnew rate for the device.
> + *
> + * This API gets the device opp table associated with this device and
> + * tries putting the device to the requested rate and the voltage domain
> + * associated with the device to the voltage corresponding to the
> + * requested rate. Since multiple devices can be assocciated with a
> + * voltage domain this API finds out the possible voltage the
> + * voltage domain can enter and then decides on the final device
> + * rate. Return 0 on success else the error value
> + */
> +int omap_device_set_rate(struct device *dev, unsigned long rate)
> +{
> + struct device_opp *dev_opp;
> + struct omap_opp *opp;
> + unsigned long volt, freq;
> + int ret;
> +
> + dev_opp = opp_find_dev_opp(dev);
> + if (IS_ERR(dev_opp)) {
> + dev_warn(dev, "%s: Unable to find device opp table\n",
> + __func__);
> + return -ENODEV;
> + }
> +
> + /* Get the possible rate from the opp layer */
> + freq = rate;
> + opp = opp_find_freq_ceil(dev, &freq);
> + if (IS_ERR(opp)) {
> + dev_err(dev, "%s: Unable to find OPP for freq%ld\n",
> + __func__, rate);
> + return -ENODEV;
> + }
> + if (unlikely(freq != rate))
> + dev_warn(dev, "%s: Available freq %ld != dpll freq %ld.\n",
> + __func__, freq, rate);
> +
> + /* Get the voltage corresponding to the requested frequency */
> + volt = opp_get_voltage(opp);
> +
> + /*
> + * Call into the voltage layer to get the final voltage possible
> + * for the voltage domain associated with the device.
> + */
> +
> + ret = omap_volt_get_final(dev_opp->volt_domain, dev, &volt);
> + if (ret) {
> + dev_err(dev, "%s: Unable to get the final volt for scaling\n",
> + __func__);
> + return ret;
> + }
> +
> + /* Do the actual scaling */
> + return omap_voltage_scale(dev_opp->volt_domain, volt);
This function also needs to be lock protected to avoid race conditions involved when multiple guys try to scale the voltage simultaneously.
> +}
> +
> +/**
> + * omap_device_get_rate - Gets the current operating rate of the device
> + * @dev - the device pointer
> + *
> + * This API returns the current operating rate of the device on success.
> + * Else returns the error value.
> + */
> +unsigned long omap_device_get_rate(struct device *dev)
> +{
> + struct device_opp *dev_opp;
> +
> + dev_opp = opp_find_dev_opp(dev);
> +
> + if (IS_ERR(dev_opp)) {
> + dev_warn(dev, "%s: Unable to find device opp table\n",
> + __func__);
> + return -ENODEV;
> + }
> +
> + if (!dev_opp->get_rate) {
> + dev_warn(dev, "%s: No get_rate API\n", __func__);
> + return -EINVAL;
> + }
> +
> + return dev_opp->get_rate(dev);
> +}
> --
> 1.7.0.rc1.33.g07cf0f
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