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Date: Wed, 10 Nov 2021 10:50:07 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Hammer Hsieh <hammerh0314@...il.com>, gregkh@...uxfoundation.org,
robh+dt@...nel.org, linux-serial@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
jirislaby@...nel.org
Cc: tony.huang@...plus.com, wells.lu@...plus.com,
Hammer Hsieh <hammer.hsieh@...plus.com>
Subject: Re: [PATCH v2 2/2] serial:sunplus-uart:Add Sunplus SoC UART Driver
Hi,
On Wed, 2021-11-10 at 15:51 +0800, Hammer Hsieh wrote:
[...]
> +struct sunplus_uart_port {
> + char name[16];
> + struct uart_port uport;
> + struct sunplus_dma_info *uartdma_rx;
> + struct sunplus_dma_info *uartdma_tx;
> + struct clk *clk;
> + struct reset_control *rstc;
> + unsigned int pllsys_rate;
> + struct gpio_desc *rts_gpio;
> + struct hrtimer rts_check_tx_empty;
> + struct hrtimer rts_delay_before_send;
> + struct hrtimer rts_delay_after_send;
> +};
> +struct sunplus_uart_port sunplus_uart_ports[UART_NR];
Does this have to be a global array? I would expect these to be
allocated in the probe function, one at a time.
[...]
> +static int sunplus_uart_probe(struct platform_device *pdev)
> +{
> + struct resource *res_mem;
> + struct uart_port *port;
> + struct clk *clk, *pllsys;
> + unsigned int pllsys_rate;
> + int ret, irq;
> + int idx_offset, idx;
> + int idx_which_uart;
> + char peri_name[16];
> +
> + if (pdev->dev.of_node) {
> + pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
> + if (pdev->id < 0)
> + pdev->id = of_alias_get_id(pdev->dev.of_node, "uart");
> + }
> +
> + idx_offset = -1;
> +
> + if (IS_UARTDMARX_ID(pdev->id))
> + idx_offset = 0;
> + else if (IS_UARTDMATX_ID(pdev->id))
> + idx_offset = UART_DMARX_NR;
> +
> + /* init txdma or rxdma */
> + if (idx_offset >= 0) {
> + clk = devm_clk_get(&pdev->dev, NULL);
Should this be requested by name? Looking at the binding, this could be
UADMA or HWUA?
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + ret = clk_prepare_enable(clk);
> + if (ret)
> + return ret;
I suggest to move this down after all required resources are available.
Otherwise you'll have to either disable the clock in the error paths, or
you are left with a running clock if anything below fails.
> + if (idx_offset == 0)
> + idx = idx_offset + pdev->id - ID_BASE_DMARX;
> + else
> + idx = idx_offset + pdev->id - ID_BASE_DMATX;
> +
> + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res_mem)
> + return -ENODEV;
> +
> + sprintf(peri_name, "PERI%d", (idx & 0x01));
> +
> + clk = devm_clk_get(&pdev->dev, peri_name);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + ret = clk_prepare_enable(clk);
Same as above.
> + if (ret)
> + return ret;
> +
> + sunplus_uartdma[idx].addr_phy =
> + (unsigned long)(res_mem->start);
> + sunplus_uartdma[idx].membase =
> + devm_ioremap_resource(&pdev->dev, res_mem);
> +
> + if (IS_ERR(sunplus_uartdma[idx].membase))
> + return PTR_ERR(sunplus_uartdma[idx].membase);
> +
> + if (IS_UARTDMARX_ID(pdev->id)) {
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return -ENODEV;
> +
> + sunplus_uartdma[idx].irq = irq;
> + } else {
> + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> + if (!res_mem)
> + return -ENODEV;
> +
> + sunplus_uartdma[idx].gdma_membase =
> + devm_ioremap_resource(&pdev->dev, res_mem);
> +
> + if (IS_ERR(sunplus_uartdma[idx].gdma_membase))
> + return -EINVAL;
> + }
> +
> + if (of_property_read_u32(pdev->dev.of_node, "which-uart", &idx_which_uart) != 0) {
> + dev_err(&pdev->dev, "\"which-uart\" is not assigned.");
> + return -EINVAL;
> + }
> +
> + if (idx_which_uart >= UART_NR) {
> + dev_err(&pdev->dev, "\"which-uart\" is not valid.");
> + return -EINVAL;
> + }
> +
> + sunplus_uartdma[idx].which_uart = idx_which_uart;
> +
> + return 0;
> + } else if (pdev->id < 0 || pdev->id >= UART_NR)
> + return -EINVAL;
> +
> + /* init uart */
> + port = &sunplus_uart_ports[pdev->id].uport;
> + if (port->membase)
> + return -EBUSY;
> +
> + memset(port, 0, sizeof(*port));
> +
> + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res_mem)
> + return -ENODEV;
> +
> + port->dev = &pdev->dev;
> + port->mapbase = res_mem->start;
> +
> + port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
> + if (IS_ERR(port->membase))
> + return PTR_ERR(port->membase);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return -ENODEV;
> +
> + uart_get_rs485_mode(port);
> + sunplus_uart_ports[pdev->id].rts_gpio =
> + devm_gpiod_get(&pdev->dev, "rts", GPIOD_OUT_LOW);
> + port->rs485_config = sunplus_uart_config_rs485;
> + sunplus_uart_ports[pdev->id].rts_check_tx_empty.function = NULL;
> + sunplus_uart_ports[pdev->id].rts_delay_before_send.function = NULL;
> + sunplus_uart_ports[pdev->id].rts_delay_after_send.function = NULL;
> + if (port->rs485.flags & SER_RS485_ENABLED)
> + sunplus_uart_rs485_on(port);
> +
> + sunplus_uart_ports[pdev->id].clk = devm_clk_get(&pdev->dev, NULL);
Here the same nameless clock as in the loop above is requested again.
Should this be UADMA or HWUA?
> + if (IS_ERR(sunplus_uart_ports[pdev->id].clk))
> + return PTR_ERR(sunplus_uart_ports[pdev->id].clk);
> +
> + ret = clk_prepare_enable(sunplus_uart_ports[pdev->id].clk);
> + if (ret)
> + return ret;
Same comment as above. Better to request the reset control before
enabling the clock, for example.
> +
> + sunplus_uart_ports[pdev->id].rstc =
> + devm_reset_control_get(&pdev->dev, NULL);
Please use devm_reset_control_get_exclusive() instead.
> +
> + if (IS_ERR(sunplus_uart_ports[pdev->id].rstc))
> + return PTR_ERR(sunplus_uart_ports[pdev->id].rstc);
> +
> + ret = reset_control_deassert(sunplus_uart_ports[pdev->id].rstc);
> + if (ret)
> + return ret;
> +
> + clk = sunplus_uart_ports[pdev->id].clk;
> + if (IS_ERR(clk))
This can't ever be true, the code above already returned in this case.
[...]
> +static int sunplus_uart_remove(struct platform_device *pdev)
> +{
> +#ifdef CONFIG_PM_RUNTIME_UART
> + if (pdev->id != 0) {
> + pm_runtime_disable(&pdev->dev);
> + pm_runtime_set_suspended(&pdev->dev);
> + }
> +#endif
> + uart_remove_one_port(&sunplus_uart_driver,
> + &sunplus_uart_ports[pdev->id].uport);
> +
> + if (pdev->id < UART_NR) {
> + clk_disable_unprepare(sunplus_uart_ports[pdev->id].clk);
> + reset_control_assert(sunplus_uart_ports[pdev->id].rstc);
> + }
What about the PERI clocks? This seems to leave them enabled.
regards
Philipp
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