[PATCH 2/2] [RFC] cpufreq: omap: scale regulator from clk notifier
Prashant Gaikwad
pgaikwad at nvidia.com
Tue Jul 17 01:20:56 EDT 2012
On Saturday 14 July 2012 05:46 AM, Mike Turquette wrote:
> This patch moves direct control of the MPU voltage regulator out of the
> cpufreq driver .target callback and instead puts that logic into a clock
> rate change notifier callback.
>
> The same frequency/voltage lookup via the OPP library is present, except
> that the calls to regulator_set_voltage are done from the clock
> framework instead of cpufreq.
>
> Ideally it would be nice to reduce the .target callback for OMAP's
> cpufreq driver to a simple call to clk_set_rate. For now there is still
> some other stuff needed there (jiffies per loop, rounding the rate, etc
> etc).
>
> Not-signed-off-by: Mike Turquette<mturquette at linaro.org>
> ---
> drivers/cpufreq/omap-cpufreq.c | 154 +++++++++++++++++++++++++---------------
> 1 file changed, 96 insertions(+), 58 deletions(-)
>
<snip>
>
> -static int __init omap_cpufreq_init(void)
> +static int mpu_clk_volt_scale_handler(struct notifier_block *nb,
> + unsigned long flags, void *data)
> {
> - if (cpu_is_omap24xx())
> - mpu_clk_name = "virt_prcm_set";
> - else if (cpu_is_omap34xx())
> - mpu_clk_name = "dpll1_ck";
> - else if (cpu_is_omap44xx())
> - mpu_clk_name = "dpll_mpu_ck";
> + struct clk_notifier_data *cnd = data;
> + unsigned long tol;
> + int ret, volt_new, volt_old;
> + struct opp *opp;
>
> - if (!mpu_clk_name) {
> - pr_err("%s: unsupported Silicon?\n", __func__);
> - return -EINVAL;
> + volt_old = regulator_get_voltage(mpu_reg);
> + opp = opp_find_freq_exact(mpu_dev, cnd->new_rate, true);
> + volt_new = opp_get_voltage(opp);
> +
> + tol = volt_new * OPP_TOLERANCE / 100;
> +
> + /* scaling up? scale voltage before frequency */
> + if (cnd->new_rate> cnd->old_rate) {
> + dev_dbg(mpu_dev, "cpufreq-omap: %d mV --> %d mV\n",
> + volt_old, volt_new);
> +
> + ret = regulator_set_voltage(mpu_reg, volt_new - tol, volt_new + tol);
> +
> + if (ret< 0) {
> + dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
> + __func__);
> + return NOTIFY_BAD;
> + }
> + }
> +
> + /* scaling down? scale voltage after frequency */
> + if (cnd->new_rate< cnd->old_rate) {
> + dev_dbg(mpu_dev, "cpufreq-omap: %d mV --> %d mV\n",
> + volt_old, volt_new);
> +
> + ret = regulator_set_voltage(mpu_reg, volt_new - tol, volt_new + tol);
> +
> + if (ret< 0) {
> + dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
> + __func__);
> + return NOTIFY_BAD;
> + }
> }
How are you checking pre and post rate change condition here? Need
switch case for event?
>
> + return NOTIFY_OK;
> +}
> +
> +static struct notifier_block mpu_clk_volt_scale_nb = {
> + .notifier_call = mpu_clk_volt_scale_handler,
> +};
> +
> +
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