Commit 4bcf7414 authored by Sebastian Reichel's avatar Sebastian Reichel

HSI: omap-ssi: add clk change support

This adds support for frequency changes of the SSI
functional clock, which may occur due to DVFS.
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-By: default avatarSebastian Reichel <sre@kernel.org>
parent 0fae1989
......@@ -134,6 +134,8 @@ struct gdd_trn {
* @gdd_tasklet: bottom half for DMA transfers
* @gdd_trn: Array of GDD transaction data for ongoing GDD transfers
* @lock: lock to serialize access to GDD
* @fck_nb: DVFS notfifier block
* @fck_rate: clock rate
* @loss_count: To follow if we need to restore context or not
* @max_speed: Maximum TX speed (Kb/s) set by the clients.
* @sysconfig: SSI controller saved context
......@@ -151,6 +153,7 @@ struct omap_ssi_controller {
struct tasklet_struct gdd_tasklet;
struct gdd_trn gdd_trn[SSI_MAX_GDD_LCH];
spinlock_t lock;
struct notifier_block fck_nb;
unsigned long fck_rate;
u32 loss_count;
u32 max_speed;
......@@ -164,6 +167,9 @@ struct omap_ssi_controller {
#endif
};
void omap_ssi_port_update_fclk(struct hsi_controller *ssi,
struct omap_ssi_port *omap_port);
extern struct platform_driver ssi_port_pdriver;
#endif /* __LINUX_HSI_OMAP_SSI_H__ */
......@@ -290,6 +290,64 @@ static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
return rate;
}
static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
void *data)
{
struct omap_ssi_controller *omap_ssi = container_of(nb,
struct omap_ssi_controller, fck_nb);
struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
struct clk_notifier_data *clk_data = data;
struct omap_ssi_port *omap_port;
int i;
switch (event) {
case PRE_RATE_CHANGE:
dev_dbg(&ssi->device, "pre rate change\n");
for (i = 0; i < ssi->num_ports; i++) {
omap_port = omap_ssi->port[i];
if (!omap_port)
continue;
/* Workaround for SWBREAK + CAwake down race in CMT */
tasklet_disable(&omap_port->wake_tasklet);
/* stop all ssi communication */
pinctrl_pm_select_idle_state(omap_port->pdev);
udelay(1); /* wait for racing frames */
}
break;
case ABORT_RATE_CHANGE:
dev_dbg(&ssi->device, "abort rate change\n");
/* Fall through */
case POST_RATE_CHANGE:
dev_dbg(&ssi->device, "post rate change (%lu -> %lu)\n",
clk_data->old_rate, clk_data->new_rate);
omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 1000); /* KHz */
for (i = 0; i < ssi->num_ports; i++) {
omap_port = omap_ssi->port[i];
if (!omap_port)
continue;
omap_ssi_port_update_fclk(ssi, omap_port);
/* resume ssi communication */
pinctrl_pm_select_default_state(omap_port->pdev);
tasklet_enable(&omap_port->wake_tasklet);
}
break;
default:
break;
}
return NOTIFY_DONE;
}
static int ssi_get_iomem(struct platform_device *pd,
const char *name, void __iomem **pbase, dma_addr_t *phy)
{
......@@ -369,6 +427,10 @@ static int ssi_add_controller(struct hsi_controller *ssi,
goto out_err;
}
omap_ssi->fck_nb.notifier_call = ssi_clk_event;
omap_ssi->fck_nb.priority = INT_MAX;
clk_notifier_register(omap_ssi->fck, &omap_ssi->fck_nb);
/* TODO: find register, which can be used to detect context loss */
omap_ssi->get_loss = NULL;
......@@ -432,6 +494,7 @@ static void ssi_remove_controller(struct hsi_controller *ssi)
int id = ssi->id;
tasklet_kill(&omap_ssi->gdd_tasklet);
hsi_unregister_controller(ssi);
clk_notifier_unregister(omap_ssi->fck, &omap_ssi->fck_nb);
ida_simple_remove(&platform_omap_ssi_ida, id);
}
......
......@@ -23,6 +23,7 @@
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/pm_runtime.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/debugfs.h>
......@@ -514,6 +515,11 @@ static int ssi_flush(struct hsi_client *cl)
pm_runtime_get_sync(omap_port->pdev);
spin_lock_bh(&omap_port->lock);
/* stop all ssi communication */
pinctrl_pm_select_idle_state(omap_port->pdev);
udelay(1); /* wait for racing frames */
/* Stop all DMA transfers */
for (i = 0; i < SSI_MAX_GDD_LCH; i++) {
msg = omap_ssi->gdd_trn[i].msg;
......@@ -550,6 +556,10 @@ static int ssi_flush(struct hsi_client *cl)
ssi_flush_queue(&omap_port->rxqueue[i], NULL);
}
ssi_flush_queue(&omap_port->brkqueue, NULL);
/* Resume SSI communication */
pinctrl_pm_select_default_state(omap_port->pdev);
spin_unlock_bh(&omap_port->lock);
pm_runtime_put_sync(omap_port->pdev);
......@@ -1302,6 +1312,16 @@ static int ssi_restore_divisor(struct omap_ssi_port *omap_port)
return 0;
}
void omap_ssi_port_update_fclk(struct hsi_controller *ssi,
struct omap_ssi_port *omap_port)
{
/* update divisor */
u32 div = ssi_calculate_div(ssi);
omap_port->sst.divisor = div;
ssi_restore_divisor(omap_port);
}
EXPORT_SYMBOL_GPL(omap_ssi_port_update_fclk);
static int omap_ssi_port_runtime_suspend(struct device *dev)
{
struct hsi_port *port = dev_get_drvdata(dev);
......
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