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

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

drivers/hsi/controllers/omap_ssi.h

+6 −0
Original line number Diff line number Diff line
@@ -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__ */

drivers/hsi/controllers/omap_ssi_core.c

+63 −0
Original line number Diff line number Diff line
@@ -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);

}

drivers/hsi/controllers/omap_ssi_port.c

+20 −0
Original line number Diff line number Diff line
@@ -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);