diff options
author | Sebastian Reichel <sre@kernel.org> | 2016-01-31 00:52:38 (GMT) |
---|---|---|
committer | Sebastian Reichel <sre@kernel.org> | 2016-05-02 19:56:25 (GMT) |
commit | 4bcf7414528a6b7ca52d28953a732a4cf36063e8 (patch) | |
tree | a70c2897861ee30a420153a94651a723a70aec1f /drivers/hsi/controllers | |
parent | 0fae198988b873d30fe9ecb6a6271afb36df97e9 (diff) | |
download | linux-4bcf7414528a6b7ca52d28953a732a4cf36063e8.tar.xz |
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: Pavel Machek <pavel@ucw.cz>
Signed-off-By: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'drivers/hsi/controllers')
-rw-r--r-- | drivers/hsi/controllers/omap_ssi.h | 6 | ||||
-rw-r--r-- | drivers/hsi/controllers/omap_ssi_core.c | 63 | ||||
-rw-r--r-- | drivers/hsi/controllers/omap_ssi_port.c | 20 |
3 files changed, 89 insertions, 0 deletions
diff --git a/drivers/hsi/controllers/omap_ssi.h b/drivers/hsi/controllers/omap_ssi.h index e493321..7b4dec2 100644 --- a/drivers/hsi/controllers/omap_ssi.h +++ b/drivers/hsi/controllers/omap_ssi.h @@ -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__ */ diff --git a/drivers/hsi/controllers/omap_ssi_core.c b/drivers/hsi/controllers/omap_ssi_core.c index 535c760..15b2a60 100644 --- a/drivers/hsi/controllers/omap_ssi_core.c +++ b/drivers/hsi/controllers/omap_ssi_core.c @@ -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); } diff --git a/drivers/hsi/controllers/omap_ssi_port.c b/drivers/hsi/controllers/omap_ssi_port.c index 1569bbb..98b22e8 100644 --- a/drivers/hsi/controllers/omap_ssi_port.c +++ b/drivers/hsi/controllers/omap_ssi_port.c @@ -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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