[PATCH v2 01/24] spi: mpc512x: cleanup clock API use

[Gerhard Sittig <gsi-ynQEQJNshbs@public.gmane.org>]

cleanup the MPC512x SoC's SPI master's use of the clock API
- get, prepare, and enable the MCLK during probe; disable, unprepare and
  put the MCLK upon remove; hold a reference to the clock over the
  period of use
- fetch MCLK rate (reference) once during probe and slightly reword BCLK
  (bitrate) determination to reduce redundancy as well as to not exceed
  the maximum text line length
- stick with the PPC_CLOCK 'psc%d_mclk' name for clock lookup, only
  switch to a fixed string later after device tree based clock lookup
  will have become available

the omission in the clock handling previously went unnoticed, but will
become fatal in the common clock scenario

Signed-off-by: Gerhard Sittig <gsi-ynQEQJNshbs@public.gmane.org>
---
 drivers/spi/spi-mpc512x-psc.c |   49 ++++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c
index 29fce6a..7a32373 100644
--- a/drivers/spi/spi-mpc512x-psc.c
+++ b/drivers/spi/spi-mpc512x-psc.c
@@ -38,7 +38,8 @@ struct mpc512x_psc_spi {
 	struct mpc512x_psc_fifo __iomem *fifo;
 	unsigned int irq;
 	u8 bits_per_word;
-	u32 mclk;
+	struct clk *clk_mclk;
+	u32 mclk_rate;
 
 	struct completion txisrdone;
 };
@@ -72,6 +73,7 @@ static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
 	struct mpc52xx_psc __iomem *psc = mps->psc;
 	u32 sicr;
 	u32 ccr;
+	int speed;
 	u16 bclkdiv;
 
 	sicr = in_be32(&psc->sicr);
@@ -95,10 +97,10 @@ static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
 
 	ccr = in_be32(&psc->ccr);
 	ccr &= 0xFF000000;
-	if (cs->speed_hz)
-		bclkdiv = (mps->mclk / cs->speed_hz) - 1;
-	else
-		bclkdiv = (mps->mclk / 1000000) - 1;	/* default 1MHz */
+	speed = cs->speed_hz;
+	if (!speed)
+		speed = 1000000;	/* default 1MHz */
+	bclkdiv = (mps->mclk_rate / speed) - 1;
 
 	ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
 	out_be32(&psc->ccr, ccr);
@@ -386,19 +388,11 @@ static int mpc512x_psc_spi_port_config(struct spi_master *master,
 {
 	struct mpc52xx_psc __iomem *psc = mps->psc;
 	struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
-	struct clk *spiclk;
-	int ret = 0;
-	char name[32];
 	u32 sicr;
 	u32 ccr;
+	int speed;
 	u16 bclkdiv;
 
-	sprintf(name, "psc%d_mclk", master->bus_num);
-	spiclk = clk_get(&master->dev, name);
-	clk_enable(spiclk);
-	mps->mclk = clk_get_rate(spiclk);
-	clk_put(spiclk);
-
 	/* Reset the PSC into a known state */
 	out_8(&psc->command, MPC52xx_PSC_RST_RX);
 	out_8(&psc->command, MPC52xx_PSC_RST_TX);
@@ -425,7 +419,8 @@ static int mpc512x_psc_spi_port_config(struct spi_master *master,
 
 	ccr = in_be32(&psc->ccr);
 	ccr &= 0xFF000000;
-	bclkdiv = (mps->mclk / 1000000) - 1;	/* default 1MHz */
+	speed = 1000000;	/* default 1MHz */
+	bclkdiv = (mps->mclk_rate / speed) - 1;
 	ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
 	out_be32(&psc->ccr, ccr);
 
@@ -445,7 +440,7 @@ static int mpc512x_psc_spi_port_config(struct spi_master *master,
 
 	mps->bits_per_word = 8;
 
-	return ret;
+	return 0;
 }
 
 static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
@@ -479,6 +474,8 @@ static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 	struct spi_master *master;
 	int ret;
 	void *tempp;
+	int psc_num;
+	char clk_name[16];
 
 	master = spi_alloc_master(dev, sizeof *mps);
 	if (master == NULL)
@@ -521,16 +518,30 @@ static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 		goto free_master;
 	init_completion(&mps->txisrdone);
 
+	psc_num = master->bus_num;
+	snprintf(clk_name, sizeof(clk_name), "psc%d_mclk", psc_num);
+	mps->clk_mclk = clk_get(dev, clk_name);
+	if (IS_ERR(mps->clk_mclk))
+		goto free_irq;
+	ret = clk_prepare_enable(mps->clk_mclk);
+	if (ret)
+		goto free_putclk;
+	mps->mclk_rate = clk_get_rate(mps->clk_mclk);
+
 	ret = mpc512x_psc_spi_port_config(master, mps);
 	if (ret < 0)
-		goto free_irq;
+		goto free_disclk;
 
 	ret = spi_register_master(master);
 	if (ret < 0)
-		goto free_irq;
+		goto free_disclk;
 
 	return ret;
 
+free_disclk:
+	clk_disable_unprepare(mps->clk_mclk);
+free_putclk:
+	clk_put(mps->clk_mclk);
 free_irq:
 	free_irq(mps->irq, mps);
 free_master:
@@ -547,6 +558,8 @@ static int mpc512x_psc_spi_do_remove(struct device *dev)
 	struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
 
 	spi_unregister_master(master);
+	clk_disable_unprepare(mps->clk_mclk);
+	clk_put(mps->clk_mclk);
 	free_irq(mps->irq, mps);
 	if (mps->psc)
 		iounmap(mps->psc);
-- 
1.7.10.4