Commit 114c69f4 authored by Suneel Garapati's avatar Suneel Garapati Committed by Andi Shyti
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i2c: thunderx: Clock divisor logic changes 



Handle changes to clock divisor logic for OcteonTX2 SoC family using
subsystem ID and using default reference clock source as 100MHz.

Signed-off-by: default avatarSuneel Garapati <sgarapati@marvell.com>
Signed-off-by: default avatarPiyush Malgujar <pmalgujar@marvell.com>
Acked-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
parent 29914dac

drivers/i2c/busses/i2c-octeon-core.c

+35 −4
Original line number Diff line number Diff line
@@ -17,9 +17,14 @@ 
#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/pci.h>



#include "i2c-octeon-core.h"



#define INITIAL_DELTA_HZ		1000000

#define TWSI_MASTER_CLK_REG_DEF_VAL	0x18

#define TWSI_MASTER_CLK_REG_OTX2_VAL	0x3



/* interrupt service routine */

irqreturn_t octeon_i2c_isr(int irq, void *dev_id)

{
@@ -658,20 +663,37 @@ int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 
void octeon_i2c_set_clock(struct octeon_i2c *i2c)

{

	int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;

	int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;

	bool is_plat_otx2;

	unsigned int mdiv_min = 2;

	/*

	 * Find divisors to produce target frequency, start with large delta

	 * to cover wider range of divisors, note thp = TCLK half period.

	 */

	unsigned int thp = TWSI_MASTER_CLK_REG_DEF_VAL, mdiv = 2, ndiv = 0;

	unsigned int delta_hz = INITIAL_DELTA_HZ;



	is_plat_otx2 = octeon_i2c_is_otx2(to_pci_dev(i2c->dev));



	if (is_plat_otx2) {

		thp = TWSI_MASTER_CLK_REG_OTX2_VAL;

		mdiv_min = 0;

	}



	for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {

		/*

		 * An mdiv value of less than 2 seems to not work well

		 * with ds1337 RTCs, so we constrain it to larger values.

		 */

		for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {

		for (mdiv_idx = 15; mdiv_idx >= mdiv_min && delta_hz != 0; mdiv_idx--) {

			/*

			 * For given ndiv and mdiv values check the

			 * two closest thp values.

			 */

			tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;

			tclk *= (1 << ndiv_idx);

			if (is_plat_otx2)

				thp_base = (i2c->sys_freq / tclk) - 2;

			else

				thp_base = (i2c->sys_freq / (tclk * 2)) - 1;



			for (inc = 0; inc <= 1; inc++) {
@@ -679,10 +701,19 @@ void octeon_i2c_set_clock(struct octeon_i2c *i2c) 
				if (thp_idx < 5 || thp_idx > 0xff)

					continue;



				foscl = i2c->sys_freq / (2 * (thp_idx + 1));

				if (is_plat_otx2)

					foscl = i2c->sys_freq / (thp_idx + 2);

				else

					foscl = i2c->sys_freq /

						(2 * (thp_idx + 1));

				foscl = foscl / (1 << ndiv_idx);

				foscl = foscl / (mdiv_idx + 1) / 10;

				diff = abs(foscl - i2c->twsi_freq);

				/*

				 * Diff holds difference between calculated frequency

				 * value vs desired frequency.

				 * Delta_hz is updated with last minimum diff.

				 */

				if (diff < delta_hz) {

					delta_hz = diff;

					thp = thp_idx;

drivers/i2c/busses/i2c-octeon-core.h

+17 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#include <linux/atomic.h>

#include <linux/bitfield.h>

#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/device.h>
@@ -7,6 +8,7 @@ 
#include <linux/i2c-smbus.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/pci.h>



/* Controller command patterns */

#define SW_TWSI_V		BIT_ULL(63)	/* Valid bit */
@@ -211,6 +213,21 @@ static inline void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data) 
	octeon_i2c_writeq_flush(data, i2c->twsi_base + TWSI_INT(i2c));

}



#define PCI_SUBSYS_DEVID_9XXX	0xB

#define PCI_SUBSYS_MASK		GENMASK(15, 12)

/**

 * octeon_i2c_is_otx2 - check for chip ID

 * @pdev: PCI dev structure

 *

 * Returns true if the device is an OcteonTX2, false otherwise.

 */

static inline bool octeon_i2c_is_otx2(struct pci_dev *pdev)

{

	u32 chip_id = FIELD_GET(PCI_SUBSYS_MASK, pdev->subsystem_device);



	return (chip_id == PCI_SUBSYS_DEVID_9XXX);

}



/* Prototypes */

irqreturn_t octeon_i2c_isr(int irq, void *dev_id);

int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);

drivers/i2c/busses/i2c-thunderx-pcidrv.c

+7 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#define PCI_DEVICE_ID_THUNDER_TWSI	0xa012



#define SYS_FREQ_DEFAULT		700000000

#define OTX2_REF_FREQ_DEFAULT		100000000



#define TWSI_INT_ENA_W1C		0x1028

#define TWSI_INT_ENA_W1S		0x1030
@@ -205,6 +206,12 @@ static int thunder_i2c_probe_pci(struct pci_dev *pdev, 
	if (ret)

		goto error;



	/*

	 * For OcteonTX2 chips, set reference frequency to 100MHz

	 * as refclk_src in TWSI_MODE register defaults to 100MHz.

	 */

	if (octeon_i2c_is_otx2(pdev))

		i2c->sys_freq = OTX2_REF_FREQ_DEFAULT;

	octeon_i2c_set_clock(i2c);



	i2c->adap = thunderx_i2c_ops;